DogAndPanda: c64games.htm



	COMPUTED FIRST BOOK OF

		COMMODORE

	64 GAMES



	COMPUTE! PublicationsJnc.fi One of the ABC Publishing Companies Greensboro, North Carolina

	Commodore 64 is a trademark of Commodore Electronics Limited.



	The following article was originally published in COMPUTE! Magazine, copyright 1981, Small System Services, Inc.: "Maze Generator" (December). The following articles were originally published in COMPUTE! Magazine, copyright 1982, Small System Services, Inc.: "Writing Your First Game" (October), "Laser Gunner" (November). The following articles were originally published in COMPUTE! Magazine, copyright 1983, COMPUTE! Publications, Inc.: "Writing an Arcade Game" (February), "Minefield" (J^une)/ "The Hawkmen Of Dindrin" (June), "Goblin" (J^uly)/ "Rats" (July), "Writing a Simulation Game" (July), "Blockhead" (August), "Diamond Drop" (September), "Mystery Spell" (September), "High Speed Mazer" (October), "Mosaic Puzzle" (October). The following articles were originally published in COMPUTE's Gazette Magazine, copyright 1983, COMPUTE! Publications, Inc.: "Adding Joysticks To Your Games" (July), "Snake Escape" (July), "Cylon Zap" (August), "The Viper" (August), "States & Capitals Tutor" (September), "Oil Tycoon" (October). Copyright 1983, COMPUTE! Publications, Inc. All rights reserved Reproduction or translation of any part of this work beyond that permitted by Sections 107 and 108 of the United States Copyright Act without the permission of the copyright owner is unlawful. Printed in the United States of America ISBN 0-942386-34-5 10 9876543 COMPUTE! Publications, Inc., Post Office Box 5406, Greensboro, NC 27403, (919) 275-9809, is a subsidiary of American Broadcasting Companies, Inc., and is not associated with any manufacturer of personal computers. Commodore 64 is a trademark of Commodore Electronics Limited.

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	Contents

	Foreword Chapter 1. The 64 as a Game Machine........... l Why the Commodore 64 Is a Great Game Machine Eric Brandon...................................... 3 Writing Your First Game Richard Mansfield.................................. 7 Writing a Simulation Game Richard Mansfield................................... 11 Writing an Arcade Game Richard Mansfield................................... 16 Adding Joysticks to Your Games Charles Brannon.................................... 20 Chapter 2. Maze Games.......................... 27 Rats! Mike Steed (64 Translation by Gregg Peek)................ 29 Goblin Dan Goff (64 Translation by Patrick Parrish).............. 36 Snake Escape Daryl Biberdorf (64 Translation by Patrick Parrish)......... 39 The Viper Dave and Casey Gardner (64 Translation by Charles Brannon).................... 44 Chapter 3. Thinking Games..................... 49 States & Capitals Tutor Enoch L. Moser.................................... 51 Mystery Spell Doug Hapeman (64 Translation by Eric Brandon).......... 58 Oil Tycoon Gordon F. Wheat (64 Translation by Chris Metcalf)......... 68 Mosaic Puzzle Bruce Jordan (64 Translation by Chris Metcalf)............. 76 Chapter 4. Dexterity.............................. 81 Blockhead Matt Gizver (64 Translation by Gregg Peek)............... 83 iii



	Diamond Drop Matt diver (64 Translation by Eric Brandon)............. 90 Laser Bounce Frank L. Broadnax.................................. 95 Chapter 5. Arcade-Style Games..................103 The Hawkmen of Dindrin Esteban V. Aguilar, Jr. (64 Version by Charles Brannon)......105 Minefield Sean Igo (64 Translation by Gregg Peele)..................113 Cylon Zap Mark Dudley (64 Translation by Gregg Peele)..............119 Laser Gunner GaryR. Lecompte (64 Translation by Philip I. Nelson).......129 Chapter 6. Machine Language Games...........135 Using the Machine Language Editor: MLX Charles Brannon....................................137 Munchmaze Gary E. Marsa (64 Translation by Gregg Peele).............144 Richthofen's Revenge Chris Metcalfand Marc Sugiyama......................151 Zuider Zee Marc Sugiyama.....................................168 Appendix A. Beginners Guide to Typing In Programs........................193 Appendix B. How to Type In Programs.........197 Appendix C. Maze Generator................... 199 Charles Bond (Translated to machine language by Gary E. Marsa and for the 64 by Gregg Peele)..............201 Appendix D. Do You Want to Write Your Own Games? Orson Scott Card....................................211 Index..............................................217 iv



	Foreword

	COMPUTE!'s First Book of Commodore 64 Games is packed full of great games. But this book serves a double purpose. First, it provides you with a variety of games, which you can merely type into the computer, save on disk or tape, and then play again and again. Second, because the full program is here in print, you can see exactly how the game's creator brought off the effects you like. In fact, to make this book as useful as possible, many of the games are accompanied by explanations of how the program works. Chapters at the beginning and end of the book will also help you learn how to write your own games. In order to make typing in the programs as easy as possible, we have included three aids. Be sure to read over the article in Appendix A "Beginner's Guide to Typing in Programs." Also, review Appendix B "How to Type in Programs." A number of the programs are written completely or partially in machine language. If you have ever typed in a machine language program with its hundreds of DATA statements, you will appreciate the "Machine Language Editor (MLX)" in Chapter 6. MLX is a BASIC program that will help you type in machine language programs perfectly the first time.

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	1 Why the Commodore 64 Is a Great Game Machine________ Eric Brandon

	One of the first things a new programmer wants to do is write a game. The programmer soon discovers that there is no "move alien around" command; rather, the computer must be told what to do in hundreds of tiny little steps. Fortunately, the Commodore 64 is loaded with features that make this arduous task much easier and reduce the number of steps that have to be programmed into the computer. The games in this book try to exploit these features as much as possible, to save the programmer time, and to save you typing. Parlez-vous BASIC? What language to program the game in is the first decision the programmer must make. On the Commodore 64 the choice is between BASIC and machine language. The native language of the computer is machine language. This means that programs written in BASIC have to be translated into machine language while they are running. That translation takes time, so BASIC programs run much slower than programs written in machine language. Although machine language is much faster, it is also a more difficult language to use; so to speed up writing the game, many programmers opt for BASIC, or some combination of BASIC and machine language. The choice ultimately depends on how critical speed is to the game. Witness the incredible speed of "Munch-maze" or "The Viper," both written in machine language. Other 3



	T The Commodore 64 As A Game Machine games where speed is not so important, such as "Mystery Spell," use no machine language at all. The 64 makes machine language programming easier because it has a popular, easy-to-use microprocessor chip, and it has areas of memory where machine language programs can be conveniently tucked away Make Your Own Alphabet Whenever you see a letter or graphic character on the screen, you are looking at one member of a character set. The character set is where the computer goes to see what a character such as A looks like, before it can put it on the screen. By holding down the SHIFT and Commodore keys, you can switch between two character sets. In one of them, character number one looks like this: A; in the other, it looks like this: a. This is very important to the game programmer, because with the 64 he can create his own character set. For example, the programmer can tell the computer that character one is a happy face. From then on, moving a happy face around on the screen is just as easy as moving any other character. Here is a short program that changes the A character into a happy face: 5 REM DISABLE INTERRUPTS AND REVEAL CHARACTER ROM 10 POKE 56334,PEEK(56334)AND254 20 POKE l,PEEK(l)AND251 25 REM COPY CHARACTER SET DOWN TO RAM 29 PRINT "PLEASE WAIT 30 SECONDS" 30 FOR 1=0 TO 2048 40 POKE 12288+1,PEEK(53248+1) 50 NEXT I 55 REM COVER UP CHARACTER ROM AND REENABLE INTERRU PTS 60 POKE l_/PEEK(l)OR4 70 POKE 56334,PEEK(56334)0R1 75 REM ENABLE NEW CHARACTER SET 80 POKE 53272,28 85 REM POKE IN HAPPY FACE OVER "A" 90 FOR 1=0 TO 7 100 READ A 110 POKE 12296+1,A 120 NEXT 130 END 195 REM EACH NUMBER IS ONE ROW OF THE DOTS THAT MA KE UP THE FACE 200 DATA 60,66,165,129,165,153,66,60



	The Commodore 64 As A Game Machine	1

	Even more powerful is the technique of telling the computer that character one looks like the left half of a spaceship, and character two like the right half. By combining redefined characters, you can create large shapes. This technique is used in "The Hawkmen of Dindrin." Another Way of Making a Spaceship Sometimes a game needs objects on the screen that can go through or over other objects, like a spaceship moving over a star-field. Not only can the 64 do this, but also it will automatically detect a collision between objects. These objects, called sprites, have a number of other useful features. Each of the 504 dots can be assigned a color independent of its neighbor, and the whole sprite can double in size either vertically or horizontally. Although only eight sprites can usually be displayed at a time, most games do not require that many. Sprites can also be used for animation. The bird in Mystery Spell is a sprite. To make the bird's wings flap, several versions of the bird were drawn, with the wings up, midway, and down. By telling the bird to look like one shape after another, the illusion of flapping wings is achieved. Small Is Beautiful Sometimes, instead of large objects, a game needs to work with pixels, the individual dots that make the image on your screen. High-resolution mode allows control over each individual dot on the screen. With high-resolution graphics it is possible to make very detailed backgrounds on the screen, over which you can move the sprites that play the game. None of the games in this book use this technique because it would require the typing in of 8000 numbers that describe each of the dots on the high-resolution screen. Color Me 64 Every good game-playing computer has the ability to put color on the screen. Some have as many as 256 different shades of colors, and some have as few as six. Just as important as how many colors a computer has is how many colors it can display at once. The 64 is very good at multicolor graphics. Any character or dot can be any one of 16 colors. Furthermore, each dot within a character or a sprite can have its own color.

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	T The Commodore 64 As A Game Machine Breaking the Sound Barrier One of the most important features of a good game is sound effects for explosions, fanfares, and other sundry noises. The Commodore 64 incorporates a minisynthesizer called the SID chip. The SID chip can make three different tones at once, so that harmony and chords are possible. You can hear this in the short songs played by "Richthofen's Revenge." Furthermore, the SID gives you control over attack, decay, sustain, and release, sophisticated sound characteristics that can make the same note sound like it came from anything from a drum to an underwater oboe. Join the Party This book is more than a book of games. The Commodore 64 is a great machine with features that allow arcade-quality games. Some of these features take practice to learn. Many of the articles include explanations of how the game was designed and how the features of the 64 were exploited. By typing in the games and reading the articles, not only will you have hours of fun playing the games, but you will also be learning many of the techniques needed to design your own games.

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	1 Writing Your First Game Richard Mansfield

	Richard Mansfield, senior editor of COMPUTE! Publications, explains the details of a simple game. A beginning programmer can learn a great deal studying this short program. If you are tempted to write your own games, go ahead. It's a good way to learn to program. Games are basically the same as any other kind of programming. Computer games fall into two broad categories: 1. imitations of old standards (checkers, Othello) and 2. games which could not be played without a computer (Space Invaders, Pac-Man). This second category is more difficult to program for several reasons. For one thing, you've got to think up a whole new, and entertaining, concept and then adjust the action until it is just hard enough to be challenging but not so difficult that people want to give up. This category (basically arcade games) is especially hard to program precisely because a good computer-only game exploits all of the computer's special attributes: speed, color, and sound. To do this well, to make things look and respond just the way you imagine them, requires a good bit of programming experience. Usually, too, several things are happening at once in an arcade game. This often means that such a program must be written in machine language, which is far faster than BASIC. High Card Slice Old standards, on the other hand, can often be the best way to get started programming games. You already know the game concept, and cards or dice or game boards are fairly easily constructed and manipulated on your computer screen. To illustrate, let's take a look at a simple simulation of one of the oldest card games, "High Card." The rules are simple: you place a bet,

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	I The Commodore 64 As A Game Machine and then you draw a card from the deck. The computer, your opponent, draws a card too, and the highest card wins the money. One simplification here is that there is no attempt to represent the cards on the screen. The entire game relies simply on words (Ace of Spades, for example) when cards are drawn. Like most computer programs, the program can be visualized as having four distinct zones: initialization, main loop, subroutines, and data tables. We can go through the steps in programming this game by looking at each zone separately. Initialization From lines 10 through 80 we are teaching the computer some basics about this game. Initialization is the activity which must take place before any of the action can begin. Computers are so fast that they will zip up through these lines and start things off in the main loop at line 100 in a flash. However, as programmers, we are aware that several preliminary events took place inside before anything else. In line 20, the computer discovers that there is a variable called DOLLARS which is set equal to 500. It sets aside a section (like a small box) in its memory which it labels DOLLARS. When the game is running, it will add or subtract from this box (lines 230-240) to keep a running total of how much money you have left to bet. From time to time (line 110), it will check the box and report to the player how much he has. The box labeled DOLLARS is called a variable because during the game the amount in it will vary. Lines 30 through 60 are simple enough—they ask the player to give his or her name. The computer memorizes it in another box called NAME$ and can now speak more personally to the player in lines 140 and 230. Also, the computer prints the rules of the game in line 60. Line 70 READs four names (the face cards) from the data tables in lines 510 on. It also makes a mental note that it already READ four items. So, when it's asked to READ again (line 80), it will start with the next unread item of data which will be CLUBS. By now, the computer has memorized a variety of important facts: the player's name, the amount of his or her betting purse, the names of the face cards, and the suits of a standard deck. In less than a second, the computer has grasped and filed away the necessary facts to go on to the main loop where all the action takes place. 8



	The Commodore 64 As A Game Machine

	The Main Loop After checking that the player has money to bet, the computer asks for the bet, checks again that the bet is possible, and then runs through one cycle of the game starting in line 160. At this point, a programmer might find it worthwhile to visualize the steps involved in the game: draw a card for the player; draw for the computer; decide who won; adjust the player's purse. Since both draws are essentially identical actions (the only difference will be that we say "Bob draws a . . ." instead of "The computer draws"), we don't need to program the draw twice. This is where subroutines come in handy. The Subroutine Twice in the main loop, we GOSUB 300. First the player, then the computer, draws. Line 310 randomly picks two numbers, the card and the suit. If line 320 finds that this selection matches the one drawn just before by the player, it goes back for another draw. Line 330 makes the name of the card be the number if it is less than 11 (a face card). Then line 340 announces the draw using three variables. The first variable (PLAYERS) is set up in either line 160 or 190 as appropriate. Then the CARDS and SUITS variables are selected from the lists that were memorized back in the initialization phase (lines 70-80). The subroutine then RETURNS to the main loop. Lines 210-240 decide and announce the winner of this round. First, if the variable CARD (the computer's card) is greater than (>) YOURCARD, the computer is declared the winner in line 240, the purse is adjusted, and the main loop is restarted (GOTO 100). If the cards are equal, nothing happens to the purse and the next round begins. Notice that we don't need to say IF YOURCARD > CARD at the start of line 230 to test if the player has won. It's the only possible thing if the computer has gotten this far. Once you've solved a particular problem, you'll find you can use the solution in many future games. This subroutine which draws cards, for instance, would work just as well for Poker, or Blackjack, or dozens of other games. Subroutines are handy not only because they can be used repeatedly within a program, but because they can also be saved and used repeatedly in future programs. So think up a simple, traditional game and teach it to your computer. There is probably no more pleasurable way to learn programming than to write a game.

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	1	The Commodore 64 As A Game Machine

	High Card

	10 REMNECESSARY INITIAL INFORMATION 20 DOLLARS=500 30 PRINT " WITH WHOM DO I HAVE THE PLEASURE" 40 PRINT " OF PLAYING HIGH CARD SLICE?" 50 INPUT NAME$ 60 PRINT " HIGH CARD WINS IN THIS GAME!" 70 DIM SUIT?(4),CARD?(14):FOR 1=11 TO 14: READ CAR D?(l):NEXT I 80 FOR 1=1 TO 4: READ SUIT?(I): NEXT I 90 REM 100 REMMAIN PROGRAM LOOP 110 PRINT:PRINT" YOU HAVE ?" DOLLARS 120 IF DOLLARS<=0 THEN PRINT" THE GAME IS OVER. YO U ARE OUT OF CASH.":END 130 PRINT"WHAT IS YOUR BET";:INPUT BET 140 IF DOLLARS<BET THEN PRINT" YOU ONLY HAVE ?"DOL LARS" TO BET,"NAME?:GOTO 130 150 YOURCARD=0:YURSUIT=0 160 PLAYER?=NAME? 170 GOSUB300 180 YOURCARD=CARD:YURSUIT=SUIT 190 PLAYER?=" THE COMPUTER" 200 GOSUB300 210 IF CARD>YOURCARD THEN GOTO 240 220 IF CARD=YOURCARD THEN PRINT " A TIE!":GOTO 100 230 PRINT NAME? " WINS": DOLLARS = DOLLARS + BET:G OTO 100 240 PRINT " THE COMPUTER WINS": DOLLARS= DOLLARS-B ET:GOTO 100 290 REM 300 REMSUBROUTINE TO DRAW THE CARDS 310 CARD=INT(RND(5)13)+2:SUIT=INT(RND(5)4)+1 320 IF CARD=YOURCARD AND SUIT=YURSUIT THEN 300:REM NO IDENTICAL DRAWS 330 IF CARD<11 THEN CARD?(CARD)=STR?(CARD) 340 PRINT PLAYER? " DRAWS THE " CARD?(CARD) " OF " SUIT?(SUIT) 350 RETURN 490 REM 500 REM* DATA TABLE* 510 DATA JACK,QUEEN/KING,ACE 520 DATA CLUBS,DIAMONDS,HEARTS,SPADES

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	1 Writing a Simulation Game Richard Mansfield

	A simulation is an imitation of life. It can be the most difficult type of game to create. Thought, rather than fast action, is important. Try the short simulation offered here, then see if you can write one of your own. There are three basic types of computer games: arcade, adventure, and simulation games. Let's briefly look at the characteristics of arcade and adventure games and then write a simulation. Realtime Action Arcade games feature what's called realtime action. Unlike chess or bridge, things happen fast. You can't sit back and plan your next move; you must react immediately to the space invaders. In other words, events take place at the same speed as they would in reality: realtime. Arcade games also have a strong appeal to the eye and ear. There is much animation, color, and sound. In fact, your ability to respond quickly and effectively depends in part on all the clues you get from the graphics and sound effects. Strategy, while often an aspect of arcade play, is clearly secondary. These games are a new kind of athletics: the fun of man versus machine. Like auto racing, arcade games are essentially isometric exercises—you don't run around; you just stay in one place flexing and unflexing your muscles, tensing and relaxing. Story and Strategy Strategy, however, is more important in "adventure" games. The emphasis is on planning ahead and solving riddles. It can be like living inside an adventure novel. There is drama, characterization, and plot. You might start out, for example, in a forest with a shovel and a trusty, if enigmatic, companion parrot. As you try to figure out what to do next, the parrot keeps saying "piny dells, piny dells." After wandering aimlessly through the trees, it

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	I The Commodore 64 As A Game Machine suddenly comes to you that the bird is saying "pine needles" and you dig through them and find a treasure map. Your "character" will travel, meet friends and enemies, and have the opportunity to pick up or ignore potentially useful items such as food, magic wands, and medicine. It's customary that you cannot haul tons of provisions. You'd have to decide whether or not to leave the shovel in the forest. Yet you might be sorry that you'd dropped it if you're involved in a cave-in later in the game. In any case, adventure games are fundamentally verbal. The computer displays the words: YOU ARE IN A BOAT ON A LAKE. NIGHT IS FALLING. to which you can respond in any number of ways. You might type: DIVE OFF BOAT. and the computer would reply that you now see an underwater cave or whatever. You move through the scenes the way a character moves through a novel. There is generally no penalty if you take time to plan your next move. It's not realtime. Imitations of Life The third category, simulation, is the least common kind of computer game. This is because to really imitate something, to simulate it effectively, you need lots of computer memory to hold lots of variables. However, memory has recently become far less expensive so we can expect to see increasingly effective simulation games. Star Trek and Hammurabi, both simulations, have long been popular home computer games. Although they are similar to adventure games, simulations are random. That is, there is no secret to discover, no puzzle to solve, no plot. Like real life, things happen with unpredictable, complex results. Here's a program which simulates investing. The key to simulating is to arrange realistic interactions between variables. Look at line 600. If there is "international unrest," the price of gold (PGLD) goes up and the price of Bundtfund stock (PB) goes down. This relationship between gold, stock, and an international crisis is true to life. Alternatively, stock goes up and gold goes down on line 700 during a "market rally." The game allows you to make investment decisions, and then a "month" passes during which the value of your investments will go up or down. In line 510, three variables are given random values. Stock can gain or lose up to 10 points (variable X), and

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	The Commodore 64 As A Game Machine	1

	gold can change by $20 an ounce (Y). Variable Z will be used to simulate flipping a coin. Also notice lines 520 and 525. In 520, we determine whether or not there will be unrest. The variable CH is just a counter. Each "month," CH is raised by one. Two conditions are required for unrest to happen: in a given month, CH must be greater than 4 and it must be less than whatever X turns out to be. If both these conditions are met, CH is reset to zero and we've got international unrest. This has the effect of creating unrest roughly every four to six months. Likewise, another rhythm is set up in line 525 to cause market rallies. In both cases, however, you cannot be certain exactly when to invest in gold or in stocks. The decision to raise or lower stock prices is made in line 530 and based on the coin toss variable, Z. Again, stocks move in opposition to gold. Prices will rise about 50 percent of the time, but you can never know what will happen in a given month. Suggested Complications This is the core, a rough sketch, of an investment simulation game. There is much you can do to make it a more effective simulation and thereby a more enjoyable game. The more variables in a simulation, the better. For example, add leverage and additional "incidents" which affect prices, improve the randomizing, and include other types of investments. You could even use a separate counter which, every five years, causes the X and Y variables to swing more widely to reflect recession/recovery cycles. As you can see, a simulation should be lifelike. It has interdependent cycles and a degree of unpredictability. Its realism derives from including a sufficient number of variables. And those variables must interact in plausible ways and with just the right amount of randomness. A simulation is a little world you create. You can define cause and effect and then fine-tune the whole thing until it seems well-balanced. Adventure and arcade games are certainly enjoyable, but this investment simulation can be built up to the point where it's just as much fun as any other kind of game. Mixing Styles Of course, these three categories—arcade, adventure, and simulation—are somewhat arbitrary. Some of the best games contain elements of each. There are adventure games with graphics—you see the forest, the shovel, the pine needles. After you say DIVE, your character jumps into a lake and the screen transforms into an

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	I fhe Commodore 64 As A Game Machine underwater scene. Likewise, arcade games can include the different "settings" so characteristic of adventure games. Popular arcade games such as Tron and Donkey Kong change the playfield as you earn more points. There are several ways to add to the appeal of our investment simulation, beyond just making it a more complex, more accurate simulation. You could add the visuals and sound of arcade games. Try creating a ticker tape across the top of the screen to show price changes and news events. Maybe add a bell sound to indicate the end of further transactions. And from adventure games you could borrow two elements: riddles and the necessity of planning ahead. One easy way to incorporate these two elements would be to make paying taxes a part of the game. After all, the closer it is to real life, the better the simulation. Investment Simulation 5 PRINT"{CLR}^M10 CASH=100000:PGLD=400 15 POKE 53272,23:REM SHIFT TO LOWER CASE 20 PB=80 31 PRINT: PRINT"BUNDTFUND IS $"PB" PER SHARE.YOU H AVE "B"l4 SPACES)SHARES. — $"PBB 33 PRINT" GOLD IS{4 SPACES}$"PGLD" PER OUNCE. {2 SPACES}YOU HAVE "GLS" OUNCES. — $"GLDPGLD 34 T=PBB+GLDPGLD 35 PRINT:PRINT" TOTAL INVESTMENTS — $"T 36 PRINT:PRINT" YOU HAVE $"CASH" TO SPEND." 40 PRINT:PRINT"GRAND TOTAL":PRINT"(INVESTMENTS + C ASH){4 SPACES}$"T+CASH 45 IFCK=1THEN500 50 PRINT: PRINT"1.BUY{2 SPACES}2.SELL{2 SPACES}3.D ONE" 60 INPUTA:IFA=3THENCK=l:GOT031 100 PRINT"WHICH?{3 SPACES}1.GOLD{4 SPACESjOR {4 SPACES}2.STOCK" 110 INPUTF 120 PRINT"HOW MANY (SHARES{3 SPACES}OR{3 SPACESjOU NCES)?" 130 INPUTN 140 IFF=1THEN160 150 PRINCE=PBN:IFA=lTHENCASH=CASH-PRICE:B=B+N:GOT 0400 155 CASH=CASH+PRICE:B=B-N:GOTO 400 160 PRICE=PGLDN:IFA=1THENCASH=CASH-PRICE:GLD=GLD+ N:GOTO400 170 CASH=CASH+PRICE:GLD=GLD-N

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	The Commodore 64 As A Game Machine

	400 GOTO50 500 PRINT"PRESS ANY KEY TO CONT" ; 503 GET C$:IF C$=""THEN 503 505 CK=0 : PRINT: PRINT" {CLR} ONE MONTH LATER ..."-.FOR T=1TO700:NEXTT:PRINT 510 X=INT((RND(l)100)/l0):Y=INT((RND(1)200)/10): Z=RND(1) 520 CH=CH+1:IFCH>4ANDCH<XTHENCH=0:GOTO600 525 IFCH=2GOTO600 5 30 IF Z>.5 THENPB=PB+X:PGLD=PGLD-Y:GOT031 540 PB=PB-X:PGLD=PGLD+Y:GOT031 600 PRINT"INTERNATIONAL UNREST...":PGLD=PGLD+2Y:P B=PB-2X:GOT031 700 PRINT"MARKET RALLY ...{2 SPACES}":PGLD=PGLD-2* Y:PB=PB+3*X:GOT031

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	1 Writing an Arcade Game Richard Mansfield ■—-—-—----—--—-■----■■-■-■- Using the memory-mapped video could help you create faster moving games. The sample program here will assist you in designing your own fast-moving game. When you bring home your computer, usually the first thing everyone expects you to do is to write an arcade game. Who's "everyone"? It could be your children, your friends, even you— anybody who is tired of spending lots of money and wants you to program a game to play at home for free. The best defense is to politely point out that: 1. Arcade games are among the hardest types of software to write. 2. Professionals, working in teams, can take a year to write one. However, it is well worth trying to write action games. You might not be able to duplicate the speed or complexity of professional games, but you can create very entertaining games of your own. After you've spent a few weeks getting familiar with BASIC and have typed in a few games, you are ready to take up the challenge. This is one of the best ways to learn some important programming techniques and to explore the graphics and sound capabilities of your computer. Ten Million IF/THENs Your main problem is going to be speed. BASIC, though fast enough for most jobs, is pretty slow when it has to keep track of ten aliens, two mother ships, torpedoes, stars, and the player's position. All these things are in motion at once. You need to have a way to control players, to detect collisions, to score points, etc. We at COMPUTE! received a letter from reader John Anderson which touches on these problems: 16



	The Commodore 64 As A Game Machine	1

	In order to make a fast, effective "arcade-style" game, I would like to know how to let my computer know where a large number of things are on the screen (like walls in a maze) without 10,000,000 IF/THEN statements. I would also like to know how to keep things, like the little figures racing around during a game, from plowing through walls and wiping them out or coming back onto the other side of the screen. As Anderson points out, the first solution that comes to mind is to use an IF/THEN test for every possible event in the game. IF the ball hits the target, THEN raise the score. IF the ball misses the target, THEN let it move one more space. And on and on. This quickly slows the action down to a crawl. POKE Ping-Pong One of the simpler arcade games is a simulation of Ping-Pong. You need to keep track of only three things: two paddles and one ball. Let's start off by solving the hardest problem. How can we bounce a ball around the screen both quickly and accurately? The key to the problem is the fact that many computers have an area set aside in RAM which is an image of what you see on screen. This is called memory-mapped video and most computers have it. It means that if you POKE into that area of RAM, a character will appear on the screen. The next RAM byte address is the next space on screen, and so on. You can use this built-in "map" to tell what is where by using the fast PEEK command, and you can move things quickly with POKEs. The example program will work on all VICs. SCR = The address where screen RAM memory starts. LN = The length of one screen line. WALL = A solid square that appears when this number is POKEd anywhere into SCR. BLANK = A blank space character that returns the screen to normal if POKEd into SCR on top of a WALL or FIGURE. FIGURE = A character that, when POKEd into SCR, looks like a ball. The memory cells holding the screen image are located in different places. The VIC determines where it starts by using the formula in line 100. First, draw a border around your screen like a picture frame. Perhaps print reversed spaces all around. (See lines 250-310.) This border is very useful. It will let you know when your ball has hit the edge.

	17



	j The Commodore 64 As A Game Machine LOC is a variable in the program that's always changing whenever the ball changes. It keeps track of the current location of the ball. What you do is keep another variable (VECTR, in this example) which holds the direction and distance of the ball's current motion. When VECTR is added to LOC, we know where to move the ball next. There are four possible directions to go in the simplest kind of animated games. Traveling up, VECTR = -LN since you subtract the number of spaces in one screen line to move the ball to the line above. Going down is + LN, right is +1, left is -1. Notice line 180. That is how the computer tells if the ball has reached a border. The next position the figure is supposed to be POKEd into is checked to see if the WALL variable is sitting there. If not, the figure is moved (lines 200-220). If there is a wall, line 190 reverses the figure's direction. If you type in the example program, you'll be on your way to making a Ping-Pong game that will be as fast as you could want. What's left is to play around with VECTR to get different angles of bounce off walls so the ball can go anywhere. Then add two movable pieces of wall (paddles) and scorekeeping. Ping-Pong 100 SCR=1024:COL=5 5 296:POKE5 3 281,0 110 WALL=160:REM WALL CHARACTER, SOLID SQUARE.TRY {SPACE}OTHER CHARACTERS. 120 LN=40 130 GOSUB 260:REM DRAW BORDER 140 LOC=SCR+LN10+LN/2:CLOC=COL+LN10+LN/2:REM SCR EEN AND COLOR LOCATION 150 VECTR=LN:REM ALSO TRY -1,+1,LN-1,LN+1,ETC. 160 BLANK=32 170 FIGURE=81:REM "BALL"CHARACTER. 180 IF PEEK(LOC+VECTR)OWALL THEN 200 190 VECTR=-VECTR:REM REVERSE DIRECTION 200 POKE LOC,BLANK:REM ERASE OLD BALL 210 LOC=LOC+VECTR:CLOC=CLOC+VECTR:REM CALCULATE NE W POSITION 220 POKELOC+54272,l:POKELOC,81:REM PLACE BALL 230 GOTO180 240 END 250 REM BORDER SUBROUTINE 260 PRINT"{CLR}";:REM CLEAR SCREEN. 270 FOR 1=0 TO LN-l:POKE SCR+I,WALL:POKE COL+I,2:N EXTI:REM TOP

	18



	The Commodore 64 As A Game Machine	1

	280 FOR 1=0 TO LN-l:POKE SCR+LN24+I,WALL:POKECOL+ LN24+I,2:NEXT I:REM BOTTOM 290 FOR 1=0 TO 24: POKESCR+ILN,WALL:POKECOL+ILN, 2:NEXTI:REM LEFT 300 FOR 1=0 TO 24:POKE SCR+LN-1+ILN,WALL:POKECOL+ LN-1+ILN,2:NEXTI:REM RIGHT 310 RETURN

	19



	Adding Joysticks to Your Games Charles Brannon

	Taking advantage of the Commodore 64's fascinating capabilities often involves PEEKs and POKEs which can be confusing at first. This article explains the essentials of using joysticks in your own BASIC programs. First of all, if you don't yet own a Commodore joystick, you can use the readily available Atari joysticks, or any Atari-compatible joystick—which gives you quite a choice. A number of custom sticks are available from outside companies. The Inside Story To really understand joysticks, you have to know how they work. Don't worry; joysticks are no more complicated than a light switch. In fact, inside the base of the joystick are five switches that act like push buttons. When you press the joystick north (up), south (down), east (right), or west (left), or press the joybutton, a switch is closed. You can also move the stick diagonally (NE, SE, SW, NW). How can four buttons give you eight directions? Simple. The joystick is designed so that diagonal movement closes two switches simultaneously Joy Bit Each switch controls one part of a memory location inside your computer. These are called bits. A bit can hold only two values— either zero or one. Zero normally means nothing, false, empty, off. One means positive, true, on. Although it may seem confusing at first, the joystick bits are reversed. When the joystick is centered (not deflected in any direction), all the bits are on. They are all ones. But if you move the joystick up, the north bit will become a zero. If you move the joystick diagonally to the lower right, both the south and east bits will become zeros. 20



	The Commodore 64 As A Game Machine	1

	Siliconomics Joysticks would be easier to use if each direction had its own separate memory location. That way, you could check the north, south, east, west, and joybutton bits separately. But to economize (and you always do when designing microchips, where the cost is more than proportional to the amount of silicon used), all the bits are grouped together into a single memory byte (eight bits = one byte). The bits are ordered like this: Value When Off Direction (Zero When On) North: 1 South: 2 West: 4 East: 8 Button: 16 As we'll explain shortly, your program will detect which way the joystick is deflected by looking at this byte. The number in the byte will be the sum of all these values. Here's how it works. Let's ignore the joybutton for a moment. If the stick is not moved, the summed value in the byte would be 15 (1 + 2 + 4 + 8 = 15). If the stick were moved up (north), the north value would become zero, and the remaining numbers would add up to 14. If the joystick were moved left (west), the west value would become zero, and the remaining numbers would add up toll. The easiest way to use the joystick is to read the memory location with the BASIC command PEEK and use IF/THEN statements to take appropriate actions for each direction. Refer to this diagram:

	14 A

	10

	11 <*---------------- 15



	13

	21



	T The Commodore 64 As A Game Machine A series of IF/THEN statements might look like this: 10 V=PEEK(56321)AND15 20 IF V=14 THEN PRINT "NORTH" 30 IF V=13 THEN PRINT "SOUTH" 40 IF V=7 THEN PRINT "EAST" 50 IF V=ll THEN PRINT "WEST" 60 IF V=6 THEN PRINT "NORTHEAST" 70 IF V=5 THEN PRINT "SOUTHEAST" 80 IF V=9 THEN PRINT "SOUTHWEST" 90 IF V=10 THEN PRINT "NORTHWEST" 100 IF V=15 THEN PRINT "CENTER" 110 GOTO 10 Line 10 reads the value of the joystick byte and keeps it in a variable, V The number 56321 is the memory location for joystick port #1. PEEK reads this location, but you won't get just values from 0-15. Other functions are also read here, such as the joybutton. The AND15 isolates the values we're looking for by turning off all the other unwanted bits. I won't explain here why this works—just take my word for it. Who's on First? You can read the second joystick (port #2) by substituting the number 56320 for 56321 in line 10. It might seem logical that the joystick which is read by PEEKing location 56320 should be the first joystick, since it has the lower number, but that's not the way it works. You can't argue with the lettering on the side of your Commodore 64 which clearly shows which is first and which is second. Also, you'll notice that the first joystick will seem to press certain keys on your keyboard. This is a hardware anomaly, but you can play some joystick games by pressing keys in the upper-left part of your keyboard. It is not a reliable method, however. Another Way Although the sample program above will read the joystick, it's not necessarily the best way. IF/THEN statements are among the slowest statements in BASIC, so if speed is important (as in games), there are better ways to go. Here's a faster method. Change line 10 to: 10 V=15-(PEEK(56321)AND 15)

	22



	The Commodore 64 As A Game Machine	1

	Now the values returned will be:

	1

	^k10

	Notice that the range is smaller here. You can now use the values as the index to an array. Watch how it works. Let's shorten the example program: 10 FOR 1=0 TO 10:READ A$:MESSAGE$(I)=A$:NEXT I 20 DATA CENTER,NORTH,SOUTH,,WEST,NORTHWEST,SOUTHWE ST,,EAST,NORTHEAST,SOUTHEAST 30 V=15-(PEEK(56321)AND15) 40 PRINT MESSAGE?(V):GOTO 30 MESSAGES (pronounced message-string) is a string array. A string array is a single variable name that holds a whole list of strings (a string is any series of characters). Each string has its own box or place in the array. We address the item in the list by calling its number. The READ loop on line 10 fills the MESSAGES array with the ten strings. If we say PRINT MESSAGE$(0) we'll get CENTER. PRINT MESSAGE$(5) gives NORTHWEST. Some of the DATA items are followed by two commas, which are separators. The computer interprets this to mean that between the commas there is a null (empty) string. It saves us from having to include items we don't need (since some of the numbers in the range 0-10 don't correspond to any joystick direction). Table Look-Up for Speed Printing the messages indirectly by using the joystick number is a form of table look-up. Instead of having the computer go through a bunch of IF/THENs, or searching a list for an answer, table lookup is direct and fast. All the answers are already determined. This is especially useful for games, where speed is important. For

		23



	T The Commodore 64 As A Game Machine example, you could use a different character for any direction the player is facing, and put them into an array to be selected by the joystick number. Tricky Techniques You can also read the joystick by masking (isolating) the bits you are looking for. Remember that each direction has a number associated with it. If we want to check for north, we just check to see if the north bit has turned to zero. If we're checking for north this way, we'lfcapture northeast and northwest as well, which we wouldn't have caught with a mere IF/THEN statement. Here we'll mask out the north bit: V=(15-PEEK(56321)AND15) AND 1 If V = 0, the joystick is not deflected north. If V = 1, the joystick is being moved north, northeast, or northwest. To check for left (west): V=(15-PEEK(56321)AND15) AND 4 If V = 0, there is no movement to the left. If V = 4 (yes, 4, not 1), the stick is being pressed left, northwest, or southwest. See how you can separate the original four directions from the eight possible ones? So, to check for any direction, use: V=PEEK(15-PEEK(56321)AND15) AND number V (or whatever variable you use) will be either zero (not deflected) or nonzero (deflected). Substitute 1, 2, 4, or 8 for number (1 = up, 2 = down, 4 = left, 8 = right). The Joybutton You can check for the joybutton, also called the fire button or trigger, with: B1=PEEK(56321)AND16 (for port #1) B2=PEEK(56320)AND16 (for port #2) A zero value means the button is pushed. A nonzero value (16) means the button is not pushed. For example, if you are waiting for the user to press the button to begin a game, you could use a loop: 500 IF (PEEK(56321)AND16)<>0 THEN 500 24



	The Commodore 64 As A Game Machine

	It's a Natural Using a joystick in your next game will make it easier to play since joysticks seem more natural than pressing keys on the keyboard. But remember that a joystick is just a tool. It will not move objects around for you — it will just tell you how the user is deflecting the joystick. There are other uses for joysticks besides games. Unlike the keyboard, with its 50-odd keys to deal with, the joystick limits input to just nine possibilities (the eight directions and the joybutton). The joystick can be used to select menu options, answer simple questions (left = no, right = yes), and even enter text (as you do with arcade games when you set the high score). Study the following example program for more ideas. Program Explanation This program contains three subroutines you can use in your own programs. Lines 10-70 just test the subroutines and show you how to use them. The subroutine at 500 will accept a yes or no answer (left = no, right = yes) and return it in A$. Lines 700-770 let the user enter a number by counting it up and down with the joystick. The number can be found in the variable C. C will not exceed the limits of MN (minimum) and MX (maximum). The user presses the joybutton to exit. Notice the POKE 198,0. Since the first joystick interferes with the keyboard, this POKE is used to clear it out. You can use the subroutine at 800 to accept a letter of the alphabet. The letter is returned as a number from 1-26 in the variable C. In the sample program (line 20), it is used to accept a three-digit string of initials. Joystick Example 10 PRINT^MENTER YOUR INITIALS:"; 20 GOSUB800:N$=N$+CHR$(C+64):IFLEN(N$)<3THEN20 30 PRINT: PRINT"HOW OLD ARE YOU? ";:GOSUB700:AGE=C 40 PRINT:PRINTN?;", YOU CLAIM TO BE";AGE;"YEARS OL D." 50 PRINT:PRINT"IS THAT TRUE?";:GOSUB500 60 PRINTA$:IFA$="YES"THENPRINT"GOOD FOR YOU":END 70 PRINT"SO WHAT IS THE TRUTH?":GOTO 30 500 REM SUBROUTINE FOR YES/NO 505 A$="" 510 V=15-(PEEK(56321)AND15) 520 IF (VAND4)>0 THEN A$="NO"

	25



	1	The Commodore 64 As A Game Machine

	530 IF (VAND8)>0 THEN A$="YES" 540 IFA$=""THEN510 550 POKE 198,0:REM GET RID OF ANY EXTRA KEYS 560 RETURN 600 REM COUNTING SUBROUTINE 610 REM C WILL CONTAIN THE COUNT 620 REM VARIABLE MX AND MN CONTROL 630 REM THE MAXIMUM AND MINIMUM 640 REM VALUES ALLOWED.{2 SPACESjUSE 650 REM GOSUB 700 FOR THE DEFAULT 660 REM (1 AND 10), OR GOSUB 710 670 REM IF YOU ALTER MX AND MN 700 MN=1:MX=99 710 C=MN 720 PRINTRIGHT$("{2 SPACES}"+STR$(C),2);"{2 LEFT}" 730 V=15-(PEEK(56321)AND15) 740 C=C+((VAND8)=8)(C<MX)-((VAND4)=4)(C>MN) 750 REM IF FIRE BUTTON PRESSED, EXIT 760 IF(PEEK(56321)AND16)=0THENPOKE198,0:PRINT" {2 RIGHT}";:RETURN 770 GOTO 720 800 REM TEXT ENTRY:SIMILAR TO NUMBER COUNTING ROUT INE 810 C=l 820 PRINT CHR$(64+C);"{LEFT}"; 830 V=15-(PEEK(56321)AND15) 840 C=C+((VAND8)=8)(C<26)-((VAND4)=4)(C>1) 850 IF(PEEK(56321)AND16)=0THENPOKE198,0:PRINT" {RIGHT}";:RETURN 860 GOTO820



	Rats!

	Mike Steed 64 Translation by Gregg Peele

	This impressive game makes you feel that you are inside a maze, not just seeing it from above. Three-dimensional views appear as hallways, doors, and corners as you struggle to find the way out. You must find your way through a maze displayed from a rat's eye view. After you have solved the maze, the program displays the top view and traces your steps. First, you are asked what maze size you want, up to 15 by 15 (you may wish to change the DIM statement in line 49—add two to the largest dimension you want — and line 43). Line 45 checks to see if the machine code has been POKEd in, so you have to wait for that only the first time. The space bar is used to move forward, and the J and L keys are used to turn left and right, respectively (turning doesn't change your location; it just gives you the view in another direction). The M key will display the top view of the maze, mark your position, and tell you in which direction you are headed. There are five machine language routines in "Rats!" LINE, as its name implies, draws a line; this routine is similar to Applesoft's HPLOT TO or Atari BASIC'S DRAWTO command. PLOT sets the hi-res cursor to the position from which the next line is to be drawn, and plots that point on the screen. The COLOR routine fills the screen with color. IMT removes everything that is not a letter or number from the screen (thus the quarter-square graphics are erased, but not the MOVE XX at the bottom of the screen), and sets all the variables used by the other routines (locations 826-837) to zero. SCR either loads or saves something to or from the screen. This routine is used to save the screen to memory after the top view of the maze has been displayed the first time, and from then on is used to display the maze almost instantly, so you have to wait only once.



	Maze Games

	Typing in the Programs Whenever you run Rats!, you must prepare the computer by first running Program 1. Tape users should not enter line 180; likewise, disk users should not enter line 190. Program 1 will automatically LOAD and RUN Program 2. Therefore, it is necessary for tape users to SAVE Program 2 immediately following Program 1, and disk users should SAVE Program 2 on the same disk as Program 1, using the filename Rats. Program 1. Rats! Part 1 100 POKE16384,0:POKE16385,0 110 POKE56578_/PEEK(56578)OR3 120 P0KE56576,(PEEK(56576)AND252)ORl 130 POKE53272,4:POKE648,128 140 POKE53280,12:POKE53281,12 145 POKE641,0:POKE642,64 150 P0KE43,1:P0KE44,64:POKE55,0:P0KE56,128:POKE646 ,1:PRINT"{CLR}" 160 REM DISK USERS ENTER LINE 180 170 REM CASSETTE USERS ENTER LINE 190 180 LOAD^MRATSⁿ,8:RUN:END:REM DISK USERS ONLY 190 POKE 198,1:POKE 631,131:END:REM CASSETTE USERS ONLY Program 2. Rats! Part 2 2 REM DISK USERS SAVE WITH THE FILENAME RATS 3 PRINT CHR$(142):GX=49152:G0T0 38 4 REM DRAW 3-D VIEW 5 N=2:A=H:B=V:FF=2t(F-l):SYS IN 6 Z=M%(A,B)FF:IF ((z/16) AND 1)=1 THEN RL=-1:G0SU B 25:GOTO 8 7 W=M%(A+S,B-R)FF:IF ((w/128) AND 1)=1 THEN RL=-1 :GOSUB 21 8 IF ((Z/64) AND 1)=1 THEN RL=l:GOSUB 25:GOTO 10 9 W=M%(A-S,B+R)*FF:IF ((w/128) AND l)=l THEN RL=1: GOSUB 21 10 IF ((Z/128) AND 1)=1 THEN 14 11 N=N+1:IF N>8 THEN 15 12 A=A+R:B=B+S:IF B<2 THEN 15 13 GOTO 6 14 GOSUB 17 15 RETURN 16 REM DRAW CENTER BACK 17 POKE HX,VX+DX(N):POKE HY,YU(N):SYS PL:POKE HY,Y D(N):SYS LI 30



	Maze Games

	18 POKE HX,VX-DX(N) : SYS LI: POKE HY,YU(N):SYS LI: PO KE HX,VX+DX(N):SYS LI 19 RETURN 20 REM DRAW BACK SIDE 21 POKE HX,VX+RLDX(N-1):POKE HY,YU(N):SYS PL:POKE HX,VX+RLDX(N):SYS LI 22 POKE HY,YD(N):SYS LI:POKE HX,VX+RLDX(N-1):SYS {SPACE}LI 23 RETURN 24 REM DRAW RIGHT OR LEFT SIDE 25 POKE HX,VX+RLDX(N-l):POKE HY,YU(N-l):SYS PL:PO KE HX,VX+RLDX(N) 26 POKE HY,YU(N):SYS LI:POKE HY,YD(N):SYS LI:POKE {SPACE}HX,VX+RL DX(N-1) 27 POKE HY,YD(N-1):SYS LI:POKE HY,YU(N-l):IF N>2 T HEN SYS LI 28 RETURN 29 REM GET KEYBOARD CHARACTER 30 GET A$:IF A$="^H THEN 30 31 RETURN 37 REM INITIALIZE 38 HX=828:HY=829:LINE=12288:PLOT=12665:INIT=12685: SCR=12725 39 FL=12726:FH=12730:TL=12734:TH=12738 40 PRINT "{CLR}{5 DOWN}{17 RIGHT}RATSi 41 PRINT "{2 DOWN}{3 RIGHT}SOLVE A MAZE FROM A RAT 'S EYE VIEW 42 INPUT "{3 DOWN}{7 RIGHTjMAZE SIZE (H,V) {3 SPACES}3,3{5 LEFT}";H,V 43 IF H<3 OR H>15 OR V<3 OR V>15 THEN 40 44 PRINT "{CLR}{DOWN}PLEASE WAIT... 45 IF PEEK(Ll)=32 AND PEEK(LI+1)=33 AND PEEK(LI+2) =48 THEN 48 46 CK=0:FOR L=12288 TO 12761:READ A:POKE L,A:CK=CK +A:NEXT:FORK=GXTOGX+2 3:READGX 47 POKEK,GX:NEXT:IF CK<>50144 THEN PRINT "{DOWN}ER ROR IN DATA STATEMENTS":STOP 48 N=HV-1:H=H+1:V=V+1:D=l 49 DIM M%(17,17),WALK(100),CUT(5),DX(8),YU(8),YD(8 ) 50 FOR J=l TO V+l:M%(l,J)=4:M%(H+l,J)=l:NEXT 51 MX=79:MY=49:VX=39:VY=24:X=VX 52 FOR J=l TO 8:DX(J)=X:YU(J)=INT(VY-XVY/VX):YD(J )=INT(VY+X(MY-VY)/VX) 53 X=INT(X7/10):NEXT 54 FOR 1=2 TO H:M%(I,V+l)=8:M%(I,1)=2:FOR J=2 TO V :M%(I_/J)=15:NEXT:NEXT 55 R=INT(H/2)+l:S=INT(V/2)+l:M%(R_#S)=15 56 PRINT "{CLR}{DOWN}GENERATING MAZE...";:GOSUB 20 00 31

Maze Games

57 REM GENERATE RANDOM MAZE (ALGORITHM FROM ROGERS

AND STRASSBERGER)

58 FOR IWALK=1 TO N

59 I=Z

60 IF M%(R-1,S)>14 THEN

61 IF M%(R,S-1)>14 THEN

62 IF M%(R+1,S)>14 THEN

63 IF M%(R,S+1)>14 THEN

I=I+1:CUT(I)=1 I=I+1:CUT(I)=2 I=I+l:CUT(l)=3 I=I+l:CUT(l)=4

64 IF 1=0 THEN 75

65 IF I<>1 THEN I=INT(RND(1)*l)+l

66 ON CUT(I) GOTO 67,69,71,73

67 M%(R,S)=M%(R,S)-(M%(R,S) AND

68 M%(R,S)=M%(R,S)-((M%(R,S)/4)

1):R=

ANDAND AND AND

GOTO 86 S=S-1 GOTO 86 R=R+1 86 1)*2:S=S+1 l)*8:GOTO 86

69 M%(R,S)=M%(R,S)-((M%(R,S)/8)

70 M%(R,S)=M%(R,S)-((M%(R,S)/2)

71 M%(R,S)=M%(R,S)-((M%(R,S)/4)

72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90

91 92 93

M%(R,S)=M%(R,S)-(M%(R,S) AND 1):GOM%(R,S)=M%(R,S)-((M%(R,S)/2) AND M%(R,S)=M%(R,S)-((M%(R,S)/8) AND

IF D=-l

IF ROH

IF S<>V

R=2:S=2:

IF R<>2

IF S<>V

R=H:S=2:


	THEN	79
	THEN	83
	THEN	82
	GOTO	84
	THEN	83
	THEN	82
	GOTO	84

S=S+l:D=-D:GOTO 84

R=R+D

IF M%(R_fS)=15 THEN 75

GOTO 59

NEXT IWALK

MH=H:MV=V:I=INT(RND(1)*(MH-1))+2

AND 1)*8

M%(I,1)=0:M%(I,2)=M%(I,2)-((M%(I,2)/8)

H=INT(RND(1)*(MH-1))+2:H1=H:V1=V

' :GOSUB 2000:G

PRINT ^M{CLR}{DOWN}MAZE COMPLETED.

OTO 105

REM DISPLAY TOP VIEW OF MAZE

HZ=INT(79/MH):VZ=INT(49/MV)

SYS IN:POKE 214,24:PRINT TAB(25);"{UP}

{9 SPACES}{HOME}";

POKE HX,l+HZ:POKE HY,1+VZ:SYS PL .-POKE HY,MV*VZ+

1:SYS LI

FOR J=l TO MV:FOR 1=2 TO MH:N=M%(I,J):X=I*HZ+1:

Y=J*VZ+1

IF ((N/2) AND 1)=1 THEN POKE HX^iPOKE HY.YiSYS

PL:POKE HX.X-HZiSYS LI IF ((N/4) AND 1)=1 THEN POKE HX^xPOKE HY.YrSYS

PL:POKE HY,Y-VZ:SYS LI NEXT .-NEXT



	jyiaze Games

	99 RETURN 100 REM MARK PLAYER'S POSITION 101 X=HHZ-l:Y=VVZ-l:POKE HX,X+l:POKE HY,Y+1:SYS {SPACE}PL 102 POKE HX_/X-HZ+2:POKE HY,Y-VZ+2:SYS LI .-POKE HY,Y +2:SYS PL 103 POKE HX,X+2:POKE HY,Y-VZ+2:SYS LI 104 RETURN 105 FOR X=l TO MHxFOR Y=l TO MV:M%(X,Y)=M%(X,Y)+M% (X,Y)16:NEXT:NEXT 106 REM PLAY 107 F=INT(RND(l)4)+l:ON F GOTO 108,109,110,111 108 R=0:S=-1:GOTO 112 109 R=+1:S=0:GOTO 112 110 R=0:S=+1:GOTO 112 111 R=-1:S=0 112 PRINT "{CLR}{DOWN}PRESS {RVS}j{OFF} TO TURN LE FT 113 PRINT "{DOWN}PRESS {RVS}l{OFF} TO TURN RIGHT 114 PRINT "{DOWN}PRESS {RVS}SPACE{OFF} TO GO FORWA RD 115 PRINT "{DOWNjPRESS {RVS}m{OFF} TO DISPLAY TOP {SPACE}VIEW OF MAZE 116 PRINT "{3 DOWN}{RVS} PRESS ANY KEY TO CONTINUE 117 GOSUB 30:PRINT "{CLR}";:SYS49152:GOSUB 5 118 REM GET KEYSTROKE 119 GOSUB 30 120 ON -(A$="J")-2(A$="L")-3(A$=" ")-4(A$="M") {SPACEJGOTO 122,124,131,136 121 GOSUB2000:GOTO 112 122 F=F-1:IF F<1 THEN F=4 123 GOTO 125 124 F=F+1:IF F>4 THEN F=l 125 ON F GOTO 126,127,128,129 126 R=0:S=-1:GOTO 130 127 R=+1:S=0:GOTO 130 128 R=0:S=+1:GOTO 130 129 R=-1:S=0 130 GOTO 135 131 Z=M%(H,V):T=Z2t(F-l):T=(T/128) AND 1:IF T=l T HEN GOSUB 2000:GOTO 119 132 NM=NM+l:POKE 214,24:PRINT TAB(25);"{UPjMOVE";N M;"{HOME}"; 133 IF NM<100 THEN WALK(NM)=F 134 H=H+R:V=V+S:IF V<2 THEN 147 135 GOSUB 5:GOTO 119 136 IF NOT MS THEN 138

	33



	^3 Maze Games

	137 POKE FL,218:POKE FH,49:POKE TL,0:POKE TH,128:S YS SC:GOTO 139 138 GOSUB 92:POKE FL,0:POKE FH,128:POKE TL,218:POK E TH,49:SYS SC:MS=-1 139 GOSUB 101:PRINT "{HOME}YOU ARE FACING ";: ON F GOTO 140,141,142,143 140 PRINT "NORTH";:GOTO 144 141 PRINT "EAST";:GOTO 144 142 PRINT "SOUTH";:GOTO 144 143 PRINT "WEST"; 144 PRINT ".{2 SPACES}PRESS ANY KEY TO":PRINT "CON TINUE":GOSUB 30 145 PRINT "{HOME}{39 SPACES}":PRINT "{8 SPACES}" 146 GOSUB 5:GOTO 119 147 GOSUB2000:V=V1:H=H1:IF MS THEN POKE FL,218:POK E FH,49:POKE TL,0:POKE TH,128 148 IF MS THEN SYS SC:GOTO 150 149 GOSUB 92 150 GOSUB 101 151 PRINT "{HOME}{DOWN}CONGRATULATIONS-YOU'RE OUT {SPACE}IN";NM;"STEP!{LEFT}{INST}S" 152 REM DRAW PATH WALKED 153 POKE HX,HHZ-HZ/2+l:POKE HY,VVZ-VZ/2+l:SYS PL 154 FOR N=l TO NM:IF N>100 THEN 158 155 F=WALK(N):V=V+(F=l)-(F=3):H=H+(F=4)-(F=2) 156 POKE HX,HHZ-HZ/2+l:POKE HY,VVZ-VZ/2+l:SYS LI 157 NEXT 158 PRINT:END 160 DATA 32, 33, 48, 173, 58, 3, 133, 2 170 DATA 173, 59, 3, 133, 195, 32, 0, 49 180 DATA 173, 62, 3, 205, 63, 3, 16, 8 190 DATA 240, 6, 32, 173, 48, 76, 3, 48 200 DATA 96, 169, 128, 24, 109, 60, 3, 56 210 DATA 237, 58, 3, 141, 63, 3, 169, 128 220 DATA 24, 109, 61, 3, 56, 237, 59, 3 230 DATA 141, 64, 3, 162, 128, 142, 66, 3 240 DATA 142, 69, 3, 232, 142, 67, 3, 142 250 DATA 68, 3, 173, 63, 3, 201, 128, 176 260 DATA 11, 169, 127, 141, 68, 3, 169, 0 270 DATA 56, 237, 63, 3, 41, 127, 141, 63 280 DATA 3, 173, 64, 3, 201, 128, 176, 11 290 DATA 169, 127, 141, 67, 3, 169, 0, 56 300 DATA 237, 64, 3, 41, 127, 141, 64, 3 310 DATA 173, 63, 3, 205, 64, 3, 176, 32 320 DATA 174, 63, 3, 172, 64, 3, 142, 64 330 DATA 3, 140, 63, 3, 173, 68, 3, 141 340 DATA 66, 3, 173, 67, 3, 141, 69, 3 350 DATA 169, 128, 141, 67, 3, 141, 68, 3 360 DATA 173, 63, 3, 74, 141, 65, 3, 169

	34



	Maze Games

	370 DATA 0, 141, 62, 3, 96, 173, 68, 3 380 DATA 56, 233, 128, 24, 109, 58, 3, 141 390 DATA 58, 3, 173, 69, 3, 56, 233, 128 400 DATA 24, 109, 59, 3, 141, 59, 3, 173 410 DATA 65, 3, 24, 109, 64, 3, 141, 65 420 DATA 3, 238, 62, 3, 173, 65, 3, 205 430 DATA 63, 3, 48, 35, 240, 33, 56, 237 440 DATA 63, 3, 141, 65, 3, 173, 66, 3 450 DATA 56, 233, 128, 24, 109, 58, 3, 141 460 DATA 58, 3, 173, 67, 3, 56, 233, 128 470 DATA 24, 109, 59, 3, 141, 59, 3, 96 480 DATA 169, 0, 133, 168, 169, 32, 133, 196 490 DATA 165, 2, 201, 80, 176, 56, 165, 195 500 DATA 201, 50, 176, 50, 234, 234, 234, 234 510 DATA 70, 2, 38, 168, 106, 38, 168, 133 520 DATA 195, 10, 10, 101, 195, 10, 10, 38 530 DATA 196, 10, 38, 196, 234, 234, 234, 133 540 DATA 195, 166, 168, 189, 99, 49, 133, 168 550 DATA 164, 2, 177, 195, 162, 15, 221, 103 560 DATA 49, 240, 4, 202, 16, 248, 96, 173 570 DATA 98, 49, 240, 6, 138, 5, 168, 170 580 DATA 208, 8, 138, 73, 255, 5, 168, 73 590 DATA 255, 170, 189, 103, 49, 164, 2, 145 600 DATA 195, 96, 1, 1, 2, 4, 8, 32 610 DATA 126, 123, 97, 124, 226, 255, 236, 108 620 DATA 127, 98, 252, 225, 251, 254, 160, 234 630 DATA 0, 173, 60, 3, 141, 58, 3, 133 640 DATA 2, 173, 61, 3, 141, 59, 3, 133 650 DATA 195, 32, 0, 49, 96, 162, 128, 160 660 DATA 0, 134, 254, 132, 253, 177, 253, 41 670 DATA 127, 201, 64, 48, 2, 169, 32, 145 680 DATA 253, 200, 208, 241, 232, 224, 132, 208 690 DATA 232, 169, 0, 170, 157, 58, 3, 232 700 DATA 224, 12, 208, 248, 96, 169, 218, 133 710 DATA 251, 169, 49, 133, 252, 169, 0, 133 720 DATA 253, 169, 128, 133, 254, 162, 4, 160 730 DATA 0, 177, 251, 145, 253, 136, 208, 249 740 DATA 230, 252, 230, 254, 202, 48, 2, 208 750 DATA 240, 96 1000 DATA 162, 0, 169, 1, 157, 0, 216, 157 1010 DATA 0, 217, 157, 0, 218, 157, 0, 219 1020 DATA 232, 208, 241, 96, 234, 234, 234, 0 2000 S0=54272:FORE=S0TOS0+28:POKEE,0:NEXT 2010 POKE54296, 15 :POKE54277, 51 :POKE54278, 211 2020 POKE 54276, 33 :POKE 54273, 63 :POKE54272, 75 2030 FORT=lTO 200 :NEXT:POKE54276, 32:F0RT=1T0 100 :NEXT 2040 FORE=S0TOS0+28:POKEE,0:NEXT 2050 RETURN

	35



	Goblin

	Dan Goff 64 Translation by Patrick Parrish

	In "Goblin," custom characters are used to create a simple yet entertaining game. The object is to capture the scowling creatures with your goblin while avoiding the many block-shaped obstacles that lie in your path. After obstacles and sad faces have been positioned, "Goblin" begins when the main character appears at the bottom of the screen. As the game progresses, the goblin moves continually upward and the player controls only its horizontal movement. The O and P keys, in conjunction with the GET command in line 260, enable the player to move the goblin left and right, respectively. Children especially like the cumulative effect of the GET statement; they make rapid key punches and then wait for the delayed effects. As each sad face is captured by the goblin, the score is updated and printed at the upper left. If the goblin successfully clears the screen of all the faces, an entirely new playfield will be provided. A game lasts as long as you wish. A single round ends when the goblin crashes into an obstacle. At this point, the remaining sad faces smile, and you are asked if you wish to play again. If you play again, your previous highest score will be posted as the new game begins. The incentive to exceed a record score makes any game more fun. Goblin 80 POKE 53280,2:POKE 53281,1 90 PRINT"{CLR}{7 DOWN}{4 RIGHT}PLEASE WAIT...DEFIN ING CHARACTERS"; 100 POKE 52,48:P0KE 56,48:CLR:P0KE56334,PEEK(56334 )AND254 105 P0KE1,PEEK(1)AND251 108 FORN=0TO2047:POKEN+12288,PEEK(N+53248):NEXTN 109 FOR N=0 TO 7:POKEN+12320,PEEK(N+54064):NEXT N 110 IFS>HSTHENHS=S 112 RESTORE:B=4:Z=1964:Zl=Z+54272:W=0:S=J:G=0

	36



	Maze Games	2

	115 VS=54296:AD=54277:SR=54278:WF=54276:LB=54272:H B=54273 120 FOR X=0TO31:READ A:POKEX+12288,A:NEXT 123 POKE l,PEEK(l)OR4:POKE56334,PEEK(56334)ORl 125 POKE 53272,(PEEK(53272)AND240)+12 130 PRINT"{CLRltGRN}{14 RIGHT}{RVS}G O B L I N" 140 PRINT"{HOME}{RED}{2 DOWN}{RVS}"SPC(17)^HHS="HS 145 PRINT"{HOME}{BLK}{22 DOWN}{RVS}0=LEFT";SPC(27) 7"P=RIGHT" 150 FOR 1=1 TO 118 160 X=INT(RND(l)680)+1144 170 IFPEEK(X)=BTHEN 160 180 POKEX,B:POKEX+54272,0:NEXTI 190 F0RI=1T036 195 G1=0 200 X=INT(RND(l)680)+1144 210 IF PEEK(X)=BORPEEK(X)=10RPEEK(X)=3THEN 200 220 IFPEEK(X+39)=BANDPEEK(X+40)=BANDPEEK(X+41)=BTH ENPOKEX,3:POKEX+54272,0:G1=1 225 IF Gl=l THEN G=G+l:GOTO 240 230 POKEX,l:POKEX+54272,0 240 NEXT I 250 POKEZ,32:Z=Z-40:Z1=Z1-40:IF Z<1144 THEN Z=Z+76 0:Zl=Zl+760 260 GET A$:IFA$="0"THENZ=Z-1:Z1=Z1-1 270 IFA$="P"THENZ=Z+1:Z1=Z1+1 280 IFPEEK(Z)=B THEN 410 290 IFPEEK(Z)=1 THEN GOSUB 330 300 POKEZ,0:POKEZ1,0:FORT=1TO220:NEXT 310 IFW=36-G THEN J=S:GOSUB350:GOTO110 320 GOTO 250 330 W=W+l:S=S+25:PRINT"{HOME}{BLU}{2 DOWN}"S:POKE {SPACE}VS,15:POKE AD_/30:POKE SR,200:POKE WF,17 340 POKEHB,71:POKELB,12:FORT=1TO90:NEXTT:POKEVS,0: POKEHB,0:POKELB,0:RETURN 350 PRINT"{H0ME}{RED}{18 DOWN}{8 RIGHT}{RVS}**** ALL RIGHTi***" 355 FORI=1TO10:GETC$:NEXTI:REM COLLECT GARBAGE 360 POKE VS^^OKE AD,30:POKE SR_#200:POKE WF_#17:F OR 1=1 TO 17 370 H=INT(RND(0)10)+21:L=INT(RND(0)*45)+210:POKE {SPACE}HB,H:POKE LB,L 380 FOR T=l TO 80:NEXT T:NEXTI:POKE VS_#0:POKE HB_#0 :POKE LB,0 400 RETURN 410 POKEZ,2:POKEVS,15:POKEAD,30:POKESR,200:POKEWF, 129:POKE HB,2:POKE LB,125 415 FOR 1=1 TO 400:NEXT I:POKE VS,15:POKE HB,0:POK E LB,0



	2	Maze Games

	420 FORX=1144T01823:IF PEEK(X)<>1THEN NEXTX 430 IFPEEK(X)=1THEN POKEX,3:NEXTX 440 J=0 445 FORI=1TO10:GET C$:NEXTI 450 PRINT"{HOME}{BLU}{20 DOWN}{RVS}PLAY AGAIN? (Y/ N)" .-POKE 646,14 465 GET C$:IF C$ = " " THEN 465 470 IFC$=^HY^MTHEN 110 490 POKE53272,21:POKE53280,14:POKE53281,6:POKE 52, 50:POKE56,50:PRINT"{CLR}SEE YA1" 500 DATA126,219,219,255,165,90,90,165,60,66,165,12 9,153,165,66,60 510 DATA 170,85,170,85,126,219,255,189,60,66,165,1 29,165,153,66,60 520 DATA 0,0,0,0,0,0,0,0

	38



	2 Snake Escape Daryl Biberdorf 64 Translation by Patrick Parrish______________________ You'll have to watch out for poisonous mushrooms as you race against the clock towards your goal in "Snake Escape" In "Snake Escape," your goal is to move a snake out of a poisonous garden. There are approximately 150 poisonous plants on the screen after you enter your skill level. The snake appears in the upper-left corner after all poisonous plants have been placed. You then attempt to get the snake to the escape hole within the time limit you chose earlier. The snake must reach the hole without hitting a poisonous plant, running into itself, or running out of time. If it reaches the escape hole safely, you will receive a bonus in addition to your score. The snake grows as it moves along; you receive one point for each body segment it adds while moving. If it runs into itself or a poisonous plant, a cross will appear in the center of the screen with your score and the number of remaining snakes. You may stop the snake if you wish by simply releasing all keys, but remember this costs you time. Strategy If you are running your snake near the left or right edges of the screen, remember that the 64 has horizontal screen wraparound. You may end up hitting a poisonous plant on the other side of the screen, so be careful! Occasionally, the snake will be cornered between plants and itself due to a miscalculation in maneuvering. Try to fill up all the spaces you can in the cornered-off area. You may lose a snake, but you will still receive a few extra points. Also, try to keep moving at all times. And watch where you're going. The direction in which the snake moves is determined in lines 200 through 230. As written, keys I (up), J (left), K (right), and M (down) move the snake. If you aren't comfortable controlling the snake with these keys, you can easily change the program to accept other key commands.

	39



	2	Maze Games

	For instance, suppose you want to use the Z key rather than the J key to move the snake left. Since location 197 reads the keyboard, you must first determine the number which is POKEd into this location when Z is pressed. Type the following line: 1 PRINT PEEK(197):FOR 1=1 TO 400:NEXT I:GOTO 1 and then RUN the program. Next press the Z key, and the number in location 197 corresponding to the Z key (12) will print repeatedly on the screen. Try some other keys, noting their values, then hit the RUN/STOP key. You are now ready to make the modification in line 200: substitute 12 for 34. RUN the program (after deleting line 1, of course); you can move the snake left with the Z key. Snake Escape 5 GOTO100 10 POKE54296, 15 :POKE54277, 17 :POKE54278, 17 15 POKE 54276, 17 :POKE 54273, 28 :POKE54272, 49 20 POKE54276,0:POKE54273,0:POKE54272,0 30 RETURN 100 SO=0:SR=3 110 GOSUB30000:GOSUB29000 120 PRINT"{CLR}" 130 GOSUB28000:GOSUB8000:GOSUB9000:GOSUB28000 140 TI$="000000" 150 CL=INT(RND(1)*7)+1:IFCL=50RCL=3THEN150 160 IFTI$=L$THENGOSUB7000:GOTO130 170 IFDH=0THENPOKEB,HC 180 POKEB,HC:POKECO,CL 190 K=PEEK(197) 200 IFK=34THENDR=-1:GOTO250:REM LEFT 210 IFK=37THENDR=1:GOTO250:REM RIGHT 220 IFK=33THENDR=-40:GOTO250:REM UP 230 IFK=36THENDR=40:GOTO250:REM DOWN 240 GOTO160 250 POKEB,BC:B=B+DR:CO=CO+DR:SO=SO+l 260 IFPEEK(B)=88THENDH=0:GOTO9500 270 IFPEEK(B)=160THENGOSUB5000:GOTO120 280 IFPEEK(B)=81THENGOTO9500 300 IFB<1024ORB>2023THENB=B-DR:CO=CO-DR 310 GOSUB10:GOTO150 4000 REM PRINT INSTRUCTIONS 4010 PRINT"{CLR}{DOWN}{BLU}{5 RIGHT}YOUR GOAL IS T O MOVE THE SNAKE OUT OF THE{2 SPACES}POISON P ATCH." 4020 PRINT"{DOWN}{GRN}{5 RIGHT}TRY TO AVOID ALL PO ISON ({BLK}X{CYN})."

	40



	Maze Games	2

	4030 PRINT"{3 DOWN}{RED}CONTROLS:":PRINT"{PUR} J= {RVS}LEFT":PRINT"{GRN} K={RVS}RIGHT" 4040 PRINT"{CYN} I={RVS}UP":PRINT"{RED} M={RVS}DOW N" 4050 PRINT"{DOWN}{RED}POINT VALUES:" 4060 PRINT"{BLU}BODY SEGMENT={RVS}1{OFF} POINT" 4070 PRINT"{2 DOWN}{RED}YOU WILL RECEIVE A BONUS F OR ESCAPING." 4080 PRINT"{3 DOWN}{PUR}{RVS}{8 RIGHT}HIT A KEY TO START " 4090 GETA$:IFA$=""THEN4090 4100 RETURN 5000 VB=0:POKE53280,3:POKE53281,1 5010 IFS=1THENVB=20 5020 IFS=2THENVB=30 5030 IFS=3THENVB=40 5035 IFS=4THENVB=50 5040 BN=FNSC(VB) 5050 PRINT"{CLR}{6 DOWN}{8 RIGHT}{BLU}...YOU HAVE {SPACE}ESCAPED 11 1" 5060 SO=SO+BN 5070 print"{2 down}{15 right}{red}{rvs}bonus{off}: {rvs}{blu}"bn"{off}" 5080 print"{2 down}{15 right}{rvs}{pur}score{off}: {rvs}{grn}"so 5090 print"{2 down}{8 right}{blu}"sr" {redjsnakes {space}remaining" 5100 POKE54296, 15 :POKE54277, 83 :POKE54278, 50 5102 FORHI=33TO 57STEP2:LO=INT(RND(0)*50)+180 5103 POKE 54276,17:FORJ=1TO60:NEXTJ:POKE 54273,HI: POKE54272,LO:NEXT 5106 F0RT=1T0 200 :NEXT:POKE54276,0:POKE54273,0:PO KE54272,0 5120 DH=2:RETURN 6000 PRINT" {CLR} {10 DOWN} {12 RIGHT} {BLU}VWVVWWV vw" 6003 print"{12 right}{blu}v{rvs}{cyn}{11 right} {off}{blu}v" 6005 print" {12 right}wwwvwww" 6010 print"{home}{11 down]113 right}{rvs}{blk} gam E" 6020 POKE54296, 15 :POKE54277, 53 :POKE54278_/ 69 6021 POKE 54276, 33 :POKE 54273, 3 :POKE54272, 244 6022 FORT=lTO 900 :NEXT:POKE54276,0:POKE54273,0:PO KE54272,0 6025 POKE36874,150:PRINT"{HOME}{11 DOWN}{18 RIGHT} {RVSHbLK} OVER " 6026 POKE54296, 15 :POKE54277, 53 :POKE54278, 69 6027 POKE 54276, 33 : POKE 54273, 2 .-POKE54272, 163

	41



	^M Maze Games

	6028 FORT=lTO 900 :NEXT:POKE54276,0:POKE54273,0:PO KE54272,0 6040 print"{3 down}{12 right}{red}play again ?" 6050 getp$:ifp§=""then6050 6060 ifp$="y"thenso=0:sr=3:lk=0:goto120 6070 ifp$<>"n"then6050 6080 print"{3 down}{17 right}bye 1{home}":end 7000 sr=sr-1:poke53280,3:poke53281,1 7010 print"{clr}{6 down} {redjwhewi you have just {space}died of exaustioni" 7020 printspc(14)"{4 down}{grn}:z{pur}score{off}: {rvs}{grn}"so 7030 printspc(9)"{5 down}{red}"sr"{blu}snakes rema INING" 7040 POKE54296, 10 :POKE54277, 31 :POKE54278, 17 7042 POKE 54276, 33 :POKE 54273, 5 :POKE54272, 71 7043 FORV0=15TO5STEP-.5:POKE54296,V0:FORT=1TO100:N EXT:NEXT 7045 POKE54276,0:POKE5427 3,0:POKE54272,0:POKE54296 ,0 7050 FORT=1TO2000:NEXT 7060 IFSR=0THEN6000 7070 RETURN 8000 POKE53280,4:POKE53281,1:PRINT"{CLR}{3 DOWN}"S PC(42)"{RED}CHOOSE YOUR SKILL:" 8005 PRINT"{2 SPACES}£ 17 T^" 8010 PRINTSPC(51)"{DOWN}{BLU}LEVEL 1=60 SECONDS" 8020 PRINTSPC(51)"{RED}LEVEL 2=45 SECONDS" 8030 PRINTSPC(51)"{GRN}LEVEL 3=30 SECONDS" 8040 PRINTSPC(51)"{PUR}LEVEL 4=15 SECONDS" 8045 PRINT"{3 DOWN}{7 RIGHT}{YEL}l{BLU}e{GRN}V {pur}e{cyn}l {red}?" 8050 gets$:ifs$=""then8050 8060 S=VAL(S$) 8070 IFS=1THENL?="000100":RETURN 8080 IFS=2THENL$="000045":RETURN 8090 IFS=3THENL$="000030":RETURN 8100 IFS=4THENL$="000015":RETURN 8110 GOTO8050 9000 POKE53280,4:POKE53281,8:PRINT"{CLR}" 9010 FORF=1TO150:D=INT(RND(1)*966)+1058 9020 POKED,88:POKED+54272,1:FORJ=l TO20:NEXTJ:POKE D+54272,0:NEXTF 9030 POKE2023,160:POKE2022,160:POKE1983,160:POKE19 82,160 9040 POKE56295,6:POKE56294,6:POKE56255,6:POKE56254 ,6 9050 POKE1943,32:POKE2021,32 9060 RETURN

	42



	Maze Games

	9500 POKE54296, 15 :POKE54277, 53 :POKE54278, 69 9505 POKE 54276, 33 :POKE 54273, 5 :POKE54272, 71 9510 FORT=lTO 900 :NEXT:POKE54276,0:POKE54273,0:PO KE54272,0 9515 POKE54296, 15 :POKE54277, 53 :POKE54278, 69 9520 POKE 54276, 33 :POKE 54273, 3 :POKE54272, 244 9525 FORT=lTO 900 :NEXT:POKE54276,0:POKE54273,0:PO KE54272,0 9530 POKE54296, 15 :POKE54277, 53 :POKE54278, 69 9533 POKE 54276, 33 :POKE 54273, 2 :POKE54272, 163 9536 FORT=lTO 900 :NEXT:POKE54276,0:POKE54273,0:PO KE54272,0 9540 SR=SR-1 9550 PRINT"{HOME}{10 DOWN}"SPC(18)"{RVS}{WHT} {RIGHT} {RIGHT}"SPC(37)"RIP"SPC(37)"{RIGHT} {RIGHT}"SPC(3 7)"{RIGHT} {RIGHT}{OFF}" 9560 FORT=1TO1000:NEXTT 9570 POKE53280,3:POKE53281,1:PRINT"{CLR}{5 DOWN}" 9580 PRINTSPC(14)"{RED}TOO BADi1" 9590 PRINT"{4 DOWN}{14 RIGHT}{RVS}{BLU}SCORE{OFF}: {RVS}{PUR}"SO"{OFF}" 9600 PRINTSPC(8)"{4 DOWN}{GRN}"SR"{BLU}SNAKES REMA INING" 9610 FORT=1TO2000:NEXTT:IFSR=0THEN6000 9620 GOTO120 10000 POKEV,15:POKES3,217:POKES3,217:POKEV,0:POKES 3,0:RETURN 28000 BC=81:HC=87:B=1024:S3=36876:CO=55296:LK=0:RE TURN 29000 DEFFNA(L)=INT(RND(1)L)+1064 29010 DEFFNSC(L)=INT(RND(1)L)+5:RETURN 30000 POKE53280,3:POKE53281,1 30010 PRINT"{CLR}{8 DOWN}{11 RIGHT}{RVS}{RED} {17 SPACES}" 30020 PRINT"{11 RIGHT}{RVS}{RED} {GRN}{15 SPACES} {RED} " 30030 PRINT"{11 RIGHT}{RVS}{RED} {GRN} SNAKE ESCAP El {RED} " 30040 PRINT"{11 RIGHT}{RVS}{RED} {GRN}{15 SPACES} {RED} " 30050 PRINT"{11 RIGHT}{RVS}{RED}{17 SPACES}" 30070 PRINT"{2 DOWN}{12 RIGHT}{BLU}INSTRUCTIONS ?" 30080 GETI$:IFI$=""THEN30080 30090 IFI$="Y"THENGOSUB4000:GOTO30120 30100 IFI$="N"THEN30120 30110 GOTO30080 30120 RETURN

	43



	The Viper

	Dave and Casey Gardner 64 Version by Charles Brannon

	"The Viper" is a fast-action game with 60 difficulty levels. A joystick is required. The Viper is a fast, furious, hungry snake. It races about, devouring its favorite food — asterisks! And the more it eats, the bigger it gets. Since snakes have a hard time growing wider, the Viper simply gets longer. Since the Viper has such sharp, venomous teeth, it must not in its haste accidentally run into its own lengthening body. To make things especially interesting, the Viper must maneuver through a maze with electric walls. One false move means certain doom. With a joystick you can experience the perils of the Viper. The program is easy to set up and play. Just follow the screen instructions. Maneuver the Viper with a joystick plugged into port one. You can choose from various difficulty levels to control the Viper's speed. You also select one of three courses — no maze, the easy maze, or the hard maze. Your score is the number of those delicious asterisks eaten multiplied by the skill level you selected, so the harder the game, the more possible points. You get twice as many points for the easy maze, and five times as many for the hard maze. A Word to Programmers In order to get the game to run fast enough, the entire main loop of the program was written in machine language. The resulting speed was so fast that delay loops had to be inserted just to slow it down to a barely playable level. If you're brave enough, try level 20 — you'll never be able to play it. If anyone can score any points on level 20 with the hard maze, it will be truly miraculous. Another feature is the word VIPER that moves about on the title screen. No, it's not high-resolution graphics, and it's not made of sprites, but rather from simple character graphics found on the keyboard. The movement works with programmable INSerts and DELetes. Again, look it over. You may be able to use the technique foranimation in your next game.

	44



	Maze Games	2

	The Viper 100 DT=60:DIM MA(DT),Q(100),1%(15) 110 I%(14)=-40:I%(13)=40:I%(11)=-1:I%(7)=1 120 I%(10)=-41:I%(6)=-39:I%(9)=39:I%(5)=41:JOY=563 21 130 F0RJ=1T0DT:READMA(J):NEXT 140 PRINT"{WHT}{CLR}"CHR$(142):C=54272:SC=1024:POK E53281_/2:POKE53280,8 150 MZ=0:P=0:DR=0 160 CURR=251:SPEED=493 52:INDEX=SPEED+1:LNGTH=INDEX +1:RTN=LN+1 170 SID=542 72:V=SID+24:S1=SID:S2=SID:S3=S2:A=2:N=2 :MM=0:S4=SID+4 180 FORI=0TO24:POKESID+I,0:NEXT:POKESID+1,25:POKES ID+5,6:POKESID+6,0 190 POKESID+24,15 200 GOSUB410:POKESID+5,6:POKESPEED,19-SK 210 FORJ=1024TO1063:POKEJ+C,7:POKEJ, 160:NEXT 220 FORJ=1064TO2024STEP40:POKEJ+C,7:POKEJ,160:NEXT 230 FORJ=2023T01984STEP-1:POKEJ+C,7:POKEJ,160:NEXT 240 FORJ=1983TO1063STEP-40:POKEJ+C,7:POKEJ,160:NEX T 250 M=INT(RND(1)1000)+SC 260 IFPEEK(M)<>32THEN250 270 POKEM,42:POKEM+C,l 280 S=INT(RND(1)1000)+SC 290 IFPEEK(S)<>32THEN280 300 POKE S,90:POKES+C,16RND(1):IF(PEEK(56321)AND1 5)=15THEN300 310 S%=S/256:POKECURR,S-S%256:POKECURR+1,S%:POKEI NDEX,0 320 POKELNGTH,N:SYS49152+5:REM MAIN LOOP GOTO 170 330 HIT=PEEK(RTN) 340 IFHIT<>160ANDHIT<>214THEN360 350 S=PEEK(CU)+256PEEK(CU+1):POKES,42:POKES+C,7:G OTO770 360 IFHIT<>42THEN320 3 70 POKESID,0:POKESID+5,9:POKES4,128:POKES4,129:P= P+l:N=N+2:FORT=1TO50:NEXT 380 POKES4,128:POKESID,0:POKESID+5,6:POKESID+24,0: POKESID+24,15 390 GOSUB880:POKEM,42:POKEM+C,1:POKESID+24,0:POKES ID+24,15 400 GOTO320 410 IFTR=1THENPRINT"{CLR}":GOTO470 420 GOSUB950 430 PRINT"{2 DOWN}{3 SPACES}GET THE ''S BUT":PRIN T"{3 SPACES}DON'T HIT ANYTHING ELSE"

	45



	J Maze Games

	440 PRINT"{2 DOWN}{3 SPACESjUSE JOYSTICK IN CONTRO L PORT ONE." 450 F0RJ=1T045:POKESID,230:POKES4,33:F0RT=1T02:NEX T:P0KES4,32:POKESID,0 460 POKESID+5,2 470 PRINT"{3 DOWN}"TAB(11)"ENTER SKILL LEVEL:" 480 PRINTTAB(10)"&85\|{RVS}{9 SPACES } 11111111112 " : SK=10 490 PRINT" {YEL}SLOW{WHT} {2 SPACES} <- [<8JJ{RVS}12 345678901234567890{OFF}{WHT} ->{2 SPACES}g63 FAST" 500 PRINTTAB(10)"{RVS}{WHT} _z{CYN} -{PUR} _Z{GRN} - {YEL} _zgl3 -E63 _ZE73 _Z{BLU} -B3I _z":PR INT 510 PRINT"{UP}"TAB(10+SK);"{WHT}t{LEFT}"; 520 J=15-(PEEK(56321)AND15):SK=SK+((JAND8)=8)(SK< 19)-((JAND4)=4)(SK>0) 530 IF(PEEK(56321)AND16)=0 THEN560 540 IF TKT THEN530 550 T=TI+5:PRINT" ":GOTO510 560 IFTR=1THENPRINT"{CLR}":GOTO610 570 PRINT CHR$(14)"{CLR}{DOWN}YOU WILL GET 2 TIMES ":PRINT" AS MANY POINTS WITH" 580 PRINT" AN EASY MAZE. 590 PRINT"{2 DOWN} YOU WILL GET 5 TIMES":PRINT" AS MANY POINTS WITH" 600 PRINT" A HARD MAZE. 610 PRINT CHR$(14)"{2 DOWN}&83 PRESS {WHT}LEFT E8\|_ FOR HARD MAZE" 620 PRINT"{DOWN} PRESS {WHT}RIGHTg83 FOR EASY MA ZE" 630 PRINT"{DOWN} PRESS {WHT}JOYBUTTONE83 FOR NO {SPACE}MAZE" 640 IFPEEK(56321)<>255 THEN640 650 MZ=0:J=PEEK(56321):IF(JAND16)=0THENPRINT"{CLR} "CHR$(142);:RETURN 660 IF(JAND15)=15 THEN650 670 PRINT"{CLR}"CHR$(142):IF(JAND4) THEN720 680 I=-1:PRINT"{HOME}{RVS}HARD MAZE" 690 FORJ=lTODT:POKESC+80+I320+MA(J)+C,3:POKESC+MA (j)+80+I320,160:NEXTJ 700 1=1+1:IFI<2 THEN690 710 MZ=1:RETURN 720 IF(JAND8)THEN570 730 I=-1:PRINT"{HOME}{RVS}EASY MAZE" 740 F0RJ=1T032:POKESC+MA(J)+C+80+320I,3:POKESC+MA (j)+80+320I,160:NEXT 750 1=1+1 :IFK2THEN740 760 MZ=2:RETURN

	46



	Maze Games

	770 POKESID,0:POKESID+5,15-.POKES4, 129 :FORJ=15T04ST EP-.1:POKESID+24,J:NEXT 780 POKESID+24,15:FORT=1TO500:NEXT:P0KES4,128:FORT =1TO200:NEXT:POKESID+5,6 790 IFMZ=1THENP=P5 800 IFMZ=2THENP=P2 810 R=P(SK+1) 820 PRINT" {CLR} {2 DOWNHyEL} YOUR SCORE: "R 830 IFR>HSTHENHS=R 840 PRINT"{2 DOWN} {CYNjHIGH SCORE:"HS 850 PRINT:PRINT"{WHT}PRESS §33{RVS}JOYBUTTON {OFF} {WHTjTO PLAY AGAIN." 860 IF(PEEK(56321)AND16)THEN860 870 GOTO140 880 M=INT(RND(1)1000)+SC:MM=0 890 IFPEEK(M)<>32THEN880 900 RETURN 910 DATA 259,260,336,337,338,341,342,343,376,383,4 11,412,413,414,415,416 920 DATA 423,424,425,426,427,428,456,463,496,497,4 98,501,502,503,579,580 930 DATA 258,259,330,331,332,333,334,345,346,347,3 48,349,418,419,420,421 940 DATA 490,491,492,493,494,505,506,507,508,509,5 78,581 950 PRINT"{CLR}{WHT} "CHR$(142);:FORI=2T039:PRINT" ^" ; :NEXT:PRINT:PRINT"{4 DOWN}" 960 PRINT" ";:FORI=2T039:PRINT"^";:NEXT 970 PRINT"{HOME}{DOWN}E3 @3 E@3 §@3 §3 @3 {SPACE}£2 @3 E3 @5\|" 980 PRINT"{2 SPACES}{RVS} £{OFF}£{RVS}£{OFF}£ {RVS}£{OFF}£{RVS}£{OFFT£{RVST£{OFFT£ {RVS}£{OFF}£{RVS}£{OFF}£ 990 PRINT" gT3{RVS} {OFF}£{RVS}£{OFF}£{RVS}£ {OFF}£&2 T3{RVS}£{OFfT£Et3{RVS}£{OFF} £g§{RVS}B§" 1000 PRINT" §2 T3 gTi g2 T3{2 SPACES}&2 T^ 12 T3 §3 T>){3 SPACES} ":IFZZ=1THEN1070 1010 IFPEEK(900)<>232THENGOSUB1130 1020 FOR CO=3 TO 7:POKE894,CO:SYS893 1030 FORI=1TO20:PRINT"{HOME}{DOWN}"CHR$(148)" {DOWN}{LEFT}"CHR$(148)" {DOWN}{LEFT}"CHR$(148 )" {DOWN}{LEFT}"CHR$(148)" {DOWN}{LEFT}" 1040 POKESID+1,CO2+I:POKES4,33:POKES4,32:NEXT 1050 FORI=1TO20:PRINT"{HOME}{DOWN} "CHR$(20)" {DOWN} "CHR$(20)"{DOWN} "CHR$(20)"{DOWN} "CHR $(20)"{DOWN} " 1060 POKESID+l,CO2+20-I:POKES4,33:POKES4,32:NEXT: NEXT

	47



	f Maze Games

	1070 F0RI=1T010:PRINT"{HOME}{DOWN}"CHR$(148)" {DOWN}{LEFT}"CHR?(148)" {DOWN}{LEFT}"CHR$(148 )" {DOWN}{LEFT}"CHR$(148)" {DOWN}{LEFT}" 1080 NEXT 1090 POKESID+1,60 1100 FORJ=l5T01STEP-1:POKE894,J:POKESID,J*10:POKES 4,33 1110 SYS893:POKES4,32:POKESID+24,J:NEXT:POKESID+1, 15:POKESID+24,15 1120 ZZ=1:RETURN 1130 FORI=893TO905:READA:POKEI_/A:NEXT 1140 PRINT"{HOME}{8 DOWN}{RVS}READY TO PLAY IN 5 S ECONDS..." 1150 DATA 169, 1, 162, 0, 157, 40, 216, 232 1160 DATA 224, 160, 208, 248, 96 1170 FORI=49152TO493 50:READA:CK=CK+A:POKEI,A:NEXT 1180 PRINT"{HOME}{8 DOWN}{30 SPACES}" 1190 IF CKO29203 THEN PRINT"ERROR IN DATA STATEME NTS i":POKE900,0:END 1200 RETURN 1210 DATA169,0,141,199,192,173,1,220 1220 DATA41,15,170,189,183,192,240,3 1230 DATA141,199,192,173,201,192,10,170 1240 DATA165,251,157,205,192,165,252,157 1250 DATA206,192,56,173,201,192,23 7,202 1260 DATA192,16,3,24,105,128,10,170 1270 DATA189,205,192,133,253,189,206,192 1280 DATA133,254,169,32,145,253,238,201 1290 DATA192,173,201,192,16,5,169,0 1300 DATA141,201,192,169,230,141,0,212 1310 DATA169,32,141,4,212,169,33,141 1320 DATA4,212,169,214,145,251,24,165 1330 DATA251,133,253,165,252,105,212,133 1340 DATA254,169,5,145,253,24,17 3,199 1350 DATA192,16,13,101,251,133,251,165 1360 DATA252,233,0,133,252,76,138,192 1370 DATA101,251,133,251,165,252,105,0 1380 DATA133,252,24,165,251,133,253,165 1390 DATA252,105,212,133,254,177,251,201 1400 DATA32,208,24,169,81,145,251,169 1410 DATA4,145,253,173,200,192,240,8 1420 DATA162,0,134,162,197,162,208,252 1430 DATA76,5,192,141,203,192,96,0 1440 DATA0,0,0,0,41,217,1,0 1450 DATA39,215,255,0,40,216,0,0

	48





		Thinking Games



	3 States & Capitals Tutor Enoch L. Moser

	"States & Capitals Tutor" in addition to being a useful tool for students who are learning the American states and capitals, also demonstrates the use of arrays in programs and the storage and retrieval of data on cassette. Both of these concepts are important to programmers, but nonprogram-mers may use States & Capitals Tutor without delving into the working details. "States & Capitals Tutor" asks a student the name of either a state or a capital, and keeps track of correct and incorrect responses. The program randomly decides whether to quiz the student on either states or capitals and also chooses the questions randomly. Questions answered correctly are not repeated. However, the program will repeat questions that are missed. And like any good teacher, States & Capitals Tutor will help students who ask for it. Students who are stumped can simply type HELP The program gives the correct answer and comes back to the troublesome question later. It also keeps track of how many times the student asks for help. When all 50 states have been correctly matched with their capitals, and if the student has not asked for help or missed any questions, he or she is rewarded with a perfect score message. A Two-Part Program The program reads the states and capitals from a disk or tape file which is generated by Program 2, "File Maker." To use these programs, follow this procedure: 1. Type in Program 1. Line 5 for tape users should be 5 OPEN 1,1,0, "STATES" Line 5 for disk users should be 5 OPEN 1,8,0, "STATES" 2. SAVE Program 1 to disk or tape. Tape users should leave the tape at its position after the SAVE.

	51



	3	Thinking Games

	3. Type in Program 2 (File Maker). Line 40 for tape users should be 40 OPEN 1,1,1, "STATES" Line 40 for disk users should be 40 OPEN 1,8,1, "STATES" 4. RUN the program. The states and capitals will be on the tape or disk under the filename STATES. (Tape users should leave the tape in its position.) 5. SAVE Program 2. 6. Rewind the tape. 7. LOAD Program 1; leave the PLAY button pressed and the tape in position when loading is complete. 8. RUN Program 1. How the Programs Work As mentioned, the File Maker program stores the states and capitals on tape or disk under the filename STATES. The main program, States & Capitals Tutor, reads this file and stores the data in ST$ (I,J), a two-dimensional array (more on this in a moment). When a right answer is given, the range of the random number generator (line 100) is decreased by one (line 205), and that state/capital is moved to the top part of the list (lines 180-200), out of the range of selection. Otherwise, the program is fairly straightforward. The definitions of the variables are: ST$ (49,1) States and capitals array. K Number of elements moved to top of list. Rl% State pointer. R2% State or capital selector. AN$ Answer. RT% Number right. WR% Number wrong. HE % Number of helps. 1$ Temporary string for exchanging data. Arrays An array is simply an ordered set of data. It may have one or more dimensions. A one-dimensional array is merely a list whose data elements are numbered starting with 0. For example, a grocery list of 20 items, numbered 0 to 19, would be a one-dimensional array with 20 data elements. To define an array, you must use a special type of variable called a subscripted variable. This takes the form AN(I), where AN

	52

Thinking Games

is the Array Name and I is the number (subscript) of the desired element. In our grocery list example, if I = 19, then AN(I) would be the last item on the list.

The array name may be any legal variable name, with $ (string variable) or % (integer variable) appended if appropriate. (This would indicate that the data contained in the array are strings or integers.)

Let's say you want a one-dimensional array with four elements. The four elements are integers (whole numbers): 21, 23, 25, and 27. The array would be represented by AN%(I). That is to say, AN% (0) = 21, AN% (1) = 23, AN% (2) = 25, and AN% (3) = 27.

A two-dimensional array is also an ordered list, but one whose elements are each an ordered list themselves. It's easier to understand if you picture it as a chart. For example, a two-dimensional array might look like this:


	1 = 0	1 = 1	1 = 2	1 = 3
J = 0	21	23	25	27
J=l	43	45	47	49
J = 2	51	53	58	59

A proper name for this array could be AN% and its elements identified as AN%(I,J). If I = 0 and J = 0, then AN%(I,J) = 21. If I = 3 and J = 2, then AN% (I,J) = 59. The advantage of arrays is that they let you store lots of numbers or other data without using lots of variables, and you can access any data element with a simple mathematical calculation. But be careful: arrays also consume big chunks of memory.

Arrays can become very complicated. It's easy to picture one-and two-dimensional arrays, but how about arrays of three or even four dimensions? Elements of three-and four-dimensional arrays are identified in the form AN%(I,J,K) and AN%(I,J,K,L), respectively.

Creating Arrays

Typically arrays are created with nested FOR/NEXT loops, each containing a READ from a DATA statement or an INPUT from a storage device. Each FOR/NEXT level creates one ordered list. For example, the following program could be used to define the contents of the two-dimensional array shown above:



	^C Thinking Games 10 DIM AN%(3,2) 20 FOR 1=0 TO 3 30 FOR J=0 TO 2 40 READ AN%(I,J) 50 NEXT J 60 NEXT I 70 DATA 21,43,51,23,45,53,25,47,58,27,49,59 The inner (or nested) FOR/NEXT loop (lines 30-50) creates the ordered list of elements in the J-dimension within each element of the I-dimension. Compare the above chart to the DATA statement in line 70 to see how the array is set up. The DIMension statement (line 10) is required to tell the computer how much memory to set aside for the array Note that dimension sizes in a DIMension statement are one less than the number of elements in the dimension. The numbers of dimensions and the number of elements in each dimension are limited only by the amount of memory available. Remember that an array can hold other types of data besides numbers. States & Capitals Tutor uses a two-dimensional string array ST$(IJ), to store the 50 states and 50 capitals. See lines 10-35 in Program 2. Storing Data Data can be added to a program by using DATA statements or keyboard inputs, or from data files stored on tape or disk. Tape or disk files work best when several programs must have access to the same data, or when a program needs several different data files, or when the amount of data you need to store exceeds memory capacity. Note that when arrays are filled from DATA statements, twice as much memory is required as when they are filled from tape or disk. Storing and retrieving data is quite simple if you adhere to a few rules. First, before information can be written to or read from a file, a communications channel between the computer and recorder must be opened with the OPEN command. This tells the computer which file is involved and in which direction the information will flow (input from the recorder into the computer, or output from the computer to the recorder). If a write is indicated in the OPEN command, the computer will write a filename. If a read is indicated, the computer will search for the requested filename and then read the file. Second, the file must be closed, after use, by the CLOSE command. This is especially important when creating a new file.

	54



	Thinking Games	3

	The third rule to watch when storing information on tape or disk is that variable types must be consistent. That is to say data stored as numeric, integer, or string variables must be read back into variables of the same type. The variable names themselves are not stored, so they can be read back into entirely different variables, as long as you don't mismatch types. Fourth, data is read back in the same order in which it was written. Therefore, the program must expect the data in exactly the same order in which it will be received. Program 1. States & Capitals Tutor 5 OPEN 1,1,0,"STATES":REM FOR DISK OPEN 1,8,0,"STA TES" 10 DIM ST$(49,1) 15 FOR 1=0 TO 49 20 FOR J=0 TO 1 25 INPUT#1,ST$(I,J) 30 NEXT J 35 NEXT I 40 CLOSE 1 45 K=0:RT%=0:WR%=0:HE%=0 48 PRINTCHR$(147) 50 PRINT"STATES TUTOR" 55 PRINT:PRINT"THIS PROGRAM TUTORS THE STUDENT IN {6 SPACES}STATES AND CAPITALS" 60 PRINT:PRINT"IF YOU DON'T KNOW AN{2 SPACES}ANSWE R,TYPE 'HELP'" 65 PRINT:PRINT"PRESS ANY KEY TO CONTINUE" 70 GET A$:IF A$=""THEN70 100 R1%=INT((50-K)RND(-RND(0))) 105 R2%=INT(2RND(1)) 110 PRINTCHR$(147) 115 IF R2%=0 THEN 130 120 PRINT"THE CAPITAL OF ":PRINTST?(Rl%,0);" IS" 125 GOTO 140 130 PRINTST$(R1%,1):PRINT:PRINT"IS THE CAPITAL OF {SPACE}WHAT STATE?" 140 INPUT AN$ 145 IF AN$=ST$(R1%,R2%)THEN170 150 IF AN$="HELP"THEN220 155 GOTO 250 170 RT%=RT%+1 175 PRINT"THAT'S RIGHT 1" 180 FOR I=0TO1 185 I$=ST$((49-K),l) 190 ST$((49-K),l)=ST$(Rl%,l) 195 ST$(R1%,I)=I$

	55



	3	Thinking Games

	200 NEXTI 205 K=K+1 210 GOTO 300 220 HE%=HE%+1 225 PRINT:PRINT"THE ANSWER IS..." 230 PRINTSPC(5)ST$(R1%,R2%) 235 GOTO 300 250 WR%=WR%+1 255 PRINT:PRINT"SORRY.THE CORRECT ANSWER IS " 260 PRINT:PRINTSPC(5)ST$(Rl%,R2%) 300 PRINT:PRINT:PRINT:PRINT 305 PRINT"YOUR SCORE IS:" 310 PRINTSPC(5)RT%;" RIGHT" 315 PRINTSPC(5)WR%;" WRONG" 320 PRINTSPC(5)HE%;" HELPS" 325 IF RT%=50THEN400 330 PRINT:PRINT"PRESS ANY KEY TO CONTINUE " 335 GET A$:IF A$=""THEN 335 340 GO TO 100 400 IF WR%+HE%=0THEN430 405 PRINT"THAT'S ALL. BUT NOT ALL YOUR ANSWERS" 406 PRINT"WERE CORRECT OR I HAD TO HELP YOU." 408 PRINT"PRESS ANY KEY TO START OVER" 410 GET A$:IF A$=""THEN410 415 GOT045 430 PRINT:PRINT"YOU DID IT 11111" 435 PRINT"A PERFECT SCORE AND I DIDN'T HELP" 440 PRINT:PRINT"PRESS ANY KEY TO START OVER" 445 GET A?:IF A$=""THEN 445 450 GOTO 45 Program 2. File Maker (Data File) 10 DIM ST$(49,1) 15 FOR 1=0 TO 49 20 FOR J=0 TO 1 25 READ ST$(I,J) 30 NEXTJ 35 NEXTI 40 OPEN 1,1,1,"STATES":REM FOR DISK OPEN 1,8,1,"ST ATES" 45 FOR 1=0 TO 49 50 FOR J=0 TO 1 55 PRINT#1,ST$(I,J) 60 NEXT J 65 NEXT I 70 CLOSE 1 75 DATA ALABAMA,MONTGOMERY,ALASKA,JUNEAU,ARIZONA,P HOENIX,ARKANSAS,LITTLE ROCK

	56



	Thinking Games	3

	80 DATA CALIFORNIA,SACRAMENTO,COLORADO,DENVER,CONN ECTICUT,HARTFORD,DELAWARE 82 DATA DOVER 85 DATA FLORIDA,TALLAHASSEE,GEORGIA,ATLANTA,HAWAII ,HONOLULU,IDAHO,BOISE 90 DATA ILLINOIS,SPRINGFIELD,INDIANA,INDIANAPOLIS, IOWA,DES MOINES,KANSAS,TOPEKA 95 DATA KENTUCKY,FRANKFORT,LOUISIANA,BATON ROUGE,M AINE,AUGUSTA,MARYLAND 97 DATA ANNAPOLIS 100 DATA MASSACHUSETTS,BOSTON,MICHIGAN,LANSING,MIN NESOTA,SAINT PAUL,MISSISSPPI 102 DATA JACKSON 110 DATA MISSOURI,JEFFERSON CITY,MONTANA,HELENA,NE BRASKA,LINCOLN,NEVADA 112 DATA CARSON CITY 115 DATA NEW HAMPSHIRE,CONCORD,NEW JERSEY,TRENTON, NEW MEXICO,SANTA FE,NEW YORK 117 DATA ALBANY 120 DATA NORTH CAROLINA,RALEIGH,NORTH DAKOTA,BISMA RCK,OHIO,COLUMBU S 125 DATA OKLAHOMA,OKLAHOMA CITY,OREGON,SALEM,PENNS YLVANIA,HARRISBURG 130 DATA RHODE ISLAND,PROVIDENCE,SOUTH CAROLINA,CO LUMBIA,SOUTH DAKOTA,PIERRE 135 DATA TENNESSEE,NASHVILLE,TEXAS,AUSTIN,UTAH,SAL T LAKE CITY,VERMONT 137 DATA MONTPELIER 140 DATA VIRGINIA,RICHMOND,WASHINGTON,OLYMPIA,WEST VIRGINIA,CHARLESTON 142 DATA WISCONSIN,MADISON 145 DATA WYOMING,CHEYENNE

	57



	Mystery Spell Doug Hapeman 64 Version by Eric Brandon_________

	This spelling game features lively graphics and sprites. It's also a clever teaching aid for parents, teachers, and students in which spelling lessons can he reviewed and then practiced. If you've ever played Hangman, you won't have any trouble learning "Mystery Spell/' Although it's similar in concept, there's a twist. Instead of a gallows you see flying blackbirds. When the game begins, the letters of the alphabet appear near the bottom of the screen, and blank spaces representing the secret word appear near the top. When you select a letter, the bird moves to the selected letter if it's a correct choice. For each incorrect choice, a blackbird descends and lands on a perch. Too many blackbirds disallow any more guesses, and the word will be spelled correctly for you. The program has 53 preselected words. You can change the words or add to the word list simply by creating your own DATA statements beginning at line 2780. The only restriction is that the last DATA entry must be an asterisk (). Animation* The most interesting feature of Mystery Spell is the animated bird. The bird flies around the top of the screen, swooping down to pick up letters or to sit on its perch, depending on whether your guesses are right or wrong. As the bird moves around, it seems to flap its wings, creating an illusion of flight. This is achieved by rapidly displaying different poses. In films, this is done by passing many frames through a projector every second. To achieve the illusion of flapping wings, we too must create a few frames of a bird in motion. Using a sprite editor program, we first drew the bird you see in Figure 1. Then, using that sprite, we designed two more birds, one with the wing up (Figure 2) and one with the wing down

	58



	Thinking Games

	(Figure 3). Using those shapes, we designed three more birds identical to the first three, but without legs. This gave us three frames for the bird carrying a letter, and three frames for the bird flying freely. We then set up the DATA statements in the program as if we were going to display six different sprites. Immediately after the screen RAM are eight memory locations that tell the 64 where in memory to find the shapes of the eight sprites. Usually these locations are at 2040 to 2047 ($07F8 to $07FF). By rapidly POKEing 2040 with the pointer to each frame, the bird seems to flap its wings. To see how this is done, look at lines 2000-2060. This is the routine which flies the bird around the top of the screen until you press a key. Line 2050 steps through the frame numbers. The actual POKEing is done at the end of line 2000. Another interesting feature of the game is that when you guess correctly, the bird swoops down to pick up a letter, and then carries it up to the word. How is that letter incorporated into the bird sprite? In the character set ROM at 53248 ($D000), the shape of each character is contained in eight bytes. Each byte is one row, and each bit is a column within that row. Depending on whether the value of that bit is 0 or 1, the pixel will be clear or set inside the character. The sprite is 24 bits wide, which is as wide as three characters. This means that by putting character shape data into every third byte within a sprite, we can make character shapes inside sprites. This technique could be used in any program which moves letters or text around smoothly. To see how this is done, look at lines 2180-2260. Lines 2180 and 2190 make the character ROM available to be PEEKed. They also turn off the keyboard. Lines 2200 to 2240 take the character data and put it in the sprites. Finally, lines 2250 and 2260 cover up the character ROM and reenable the keyboard.

	59



	3	Thinking Games

	Figure 1. Sprite-Created Bird



	Figure 2. Bird with Wing Up fc pi.

	Figure 3. Bird with Wing Down BffiBf

	60



Mystery Spell

100 110 120 130 140 150 160 170		GOSUB 2660 X=RND(-TI) DIM W(20),W$(500) GOSUB 1190 :REM DRAW HOUSE PRINT"{HOME}{BLU}PLEASE WAIT... GOSUB 1380 :REM POKE IN SPRITES GOSUB 1970 :REM GET WORDS	SPRITES
100 110 120 130 140 150 160 170		GOSUB 690{2 SPACES}:REM SET UP	SPRITES
180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360 370 380 390 400 410 420 430 440 450 460	PRINT"{HOME}{14 SPACES}" W$=W$(RND(1)*N+1) GOSUB 650 L$=" ABCDEFGHIJKLMNOPQRSTUVWXYZ" PRINT"{HOME}{17 DOWN}{8 RIGHT}"; FOR 1=2 TO 14 PRINTMID?(L$,I,1)"{RIGHT}"; NEXT PRINT .-PRINT "{DOWN} {8 RIGHT}"; FOR 1=15TO 27 PRINTMID?(L$,I,1)"{RIGHT}"; NEXT PRINT"{HOME}{4 DOWN}"SPC(18-LEN(G$)); FOR I=1T0 LEN(G$) PRINTMID?(G§,I,1)"{RIGHT}"; NEXT IF COUNT<>LEN(W$) THEN420 POKE 198,0 FOR DL=1TO100:NEXTDL:CL=CL+1:IFCL=3THENCL=1 PRINTMID$("{BLK}{CYN}",CL,1); PRINT"{HOME}{14 SPACES}YOU WIN Ml!" GETA$:IFA$=""THEN 360 GOTO 2610 GOSUB 2000 GETA$:IFA$<"A"ORA$>"Z"ANDA$<>"VTHEN410 IF A$="<-"THEN 760 P=ASC(A§)-64 IF MID$(L$,P+1,1)<>" "THEN540
	PRINT"{HOME}{4 DOWN}{8 SPACES}LETTER			ALREADY C
470 480 490 500 510 520 530 540 550	HOSEN{10 SPACES}" FOR 1=1 TO 800:NEXTI PRINT"{HOME}{4 DOWN}{38 SPACES}" PRINT"{HOME}{4 DOWN}"SPC(18-LEN(G$)); FOR I=1T0 LEN(G$) PRINTMID?(G$,I,1)"{RIGHT}"; NEXT GOTO 420 L$=LEFT$ (L$ , P) + " "-HMID$ (L$ , P+2 ) RF=0 :REM FLAG FOR CORRECT GUESS			ALREADY C

61



	■i Thinking Games

	560 FOR 1=1 TO LEN(W?) 570 IF MID$(W$,I,1)<>A$ THEN 610 580 G$=LEFT$(G$,l)+MID$(W$,I,1)+MID$(05,1+2) 590 RF=RF+1 600 C0UNT=C0UNT+1 610 NEXT I 620 IF RF=0 THEN GOSUB 1030 630 IF RF THEN GOSUB 2070 640 GOTO 220 650 G$ = " " 660 FOR 1=1 TO LEN(W$):G$=G$+"-":W(l)=0:NEXT 670 RETURN 680 1=1+1:GOTO1980 690 REM SET UP SPRITES 700 V=53248 710 FOR 1=0 TO 15:POKE V+I,0:NEXT 720 POKE V+21,255 730 FOR I=V+39 TO V+46:POKE 1,0:NEXT 740 X=0:Y=60:S=251 7 50 RETURN 760 PRINT"{HOME}{BLU}ENTER YOUR GUESS: 770 POKE V+21,PEEK(V+21)AND254 780 FOR 1=1 TO LEN(WS):PRINT^Mi@a^M;:NEXT 790 PRINT"{HOME}{18 RIGHT}";GU$; 800 IF LEN(GU$)<LEN(W$)THENPRINT"£ + 5\|"; 810 IF LEN(GU$)<LEN(W$)-1 THEN FOR 1=2 TO LEN(W$)- LEN(GU?):PRINT^Mg@3"; 820 GET K$:IF K$=""THEN 820 830 IF K$=CHR$(20) AND LEN(GU$)>0 THEN GU$=LEFT$(G U$,LEN(GU$)-1):GOTO790 840 IF K$=CHR$(13) AND LEN(GU$)=LEN(W$) THEN 870 850 IF K$>="A" AND K$<="Z" AND LEN(GU$)<LEN(W$) TH EN GU$=GU$+K$ 860 GOTO 790 870 IF GU$<>W$ THEN 930 880 PRINT"{HOME}{38 SPACES}" 890 PRINT"{HOME}{4 DOWN}"SPC(18-LEN(" "+W?)); 900 FOR I=1T0 LEN(" "+W$) 910 PRINTMID$(" "+W$,1,1)"{RIGHT}"; 920 NEXT:GOTO350 930 PRINT"{HOME}{BLK}{13 SPACES}SORRY... YOU LOSE {5 SPACES}" 940 PRINT"{BLK}THE WORD WAS ..." 950 PRINT"{HOME}{4 DOWN}"SPC(18-LEN(" "+W§)); 960 FOR I=1T0 LEN(" "+W$) 970 PRINTMID$(" "+W$,I,1)"{RIGHT}"; 980 FOR D=l TO 200:NEXT 990 NEXT 1000 POKE 198,0

	62



	Thinking Games	3

	1010 GETA$:IFA$=""THEN1010 1020 GOTO 2610 1030 DB=DB+l:S=S-3 1040 DX=32DB+16:DY=225 1050 IF DB=8 THEN DB=0 1060 POKEV,XAND255:POKEV+16,PEEK(V+16)AND2540R-(X> 255):POKE V+l,Y:POKE2040,S 1070 IF X=0 THEN POKE V+21,PEEK(V+21)ORl 1080 FLAG=0 1090 IFABS(X-DX)>1THENX=X+3:FLAG=1:IFX>344THEN X=0 :POKEV+21,PEEK(V+21)AND254 1100 IF Y<DY THEN Y=Y+2:FLAG=1 1110 S=S+1:IFS=251THENS=248 1120 IF FLAG THEN 1060 1130 X=DX:Y=DY 1140 POKEV+2DB,XAND255:POKEV+16,PEEK(V+16)OR(2tDB )(-(X>255)) 1150 POKEV+2DB+1,Y:POKE2040+DB,254 1160 IF DB<>0 THEN POKE V+21,PEEK(V+21)AND254 1170 X=0:Y=60:IF DB=0 THEN 930 1180 RETURN 1190 POKE 53281,3:POKE 53280,4 1200 PRINT" {CYNHCLR} 1210 PRINT"{4 DOWN} 1220 PRINT _w _w 1230 PRINT"{5 SPACES}{GRN}{3 SPACES}{RVS} {2 SPACES}{OFF}{10 SPACES}{WHT}Ed3{UP}{RVS} Bb3{off}{down}{6 spaces}{grn} 1240 PRINT"{6 SPACES}{RVS}BK3{4 SPACES}{OFF} BJ\|{6 SPACES}{RVS}{YEL}£B3{BLK}{OFF} B2 G^{3 SPACES}{GRN} {RVSJEJ3 §L3{OFF} 1250 PRINT" {6 SPACES }{RVS}gJ3{4 SPACES} &L>\| {OFF}{5 SPACES}{RVS}{YEL}£{2 SPACES}B3 {OFF}{BLK}EG3{3 SPACES}{GRN} {RVS} {3 SPACES}{OFF} 1260 PRINT"{6 SPACES}{RVS}EG3{4 SPACES}EN3 {OFF}{4 SPACES}{RVS}{YEL}£{4 SPACES}£*§ {OFF}{GRN}{3 SPACES}{RVS}IJ§{3 SPACESJEU {OFF} 1270 PRINT"{6 SPACES}{RVS}{6 SPACES}{OFF} {4 SPACES}{RVS}{RED}{4 SPACES}g£3 {OFF} {GRN}{3 SPACES}{RVS}{5 SPACES}{OFF} 1280 PRINT"{6 SPACES}£53{2 SPACES}{RVS} {2 SPACES} {OFF} {6 SPACES } {RVS } {RED } g£>\| {4 SPACES}{OFF}{2 SPACES}{GRN}{3 SPACES}{RVS} isa {off} 1290 PRINT"{RVS}B63{8 SPACES}g53l2 SPACES} g63{6 SPACES}{RED}{2 SPACES}&l3&F§ g£iB68{5 SPACES}g53 §63{l2 SPACES}";

	63



	3	Thinking Games

	1300 PRINT" {8 SPACES } g53 { 2 SPACES }£65] {6 SPACES}{RED}{2 SPACES}{OFF} {RVS}£K3 [2 SPACES}£63{5 SPACES}B53 g6\| {12 SPACES}"; 1310 PRINT"B63{RVS}"; 1320 FOR 1=0 TO 8:PRINT"{40 SPACES}";:NEXT 1330 FOR 1=1 TO 8 : L=1024+2340+I4 :POKE L,114:P OKEL+54272,0:NEXT 1340 FOR 1=0 TO 39:POKE 1024+2440+1,160:POKE 5529 6+2440+1,13:NEXT 1350 PRINT"{HOME} 1360 PRINT"{BLK} 1370 RETURN 1380 1=15872:IFPEEK(l+l)=96THENFORI=lT0646+2:READ A:NEXT:RETURN 1390 READ A:IF A=256 THEN 1410 1400 POKE I,A:1=1+1:GOTO 1390 1410 FOR 1=0 TO 63:POKE 25464+1,PEEK(249*64+1):NE XT:RETURN 1420 DATA 0,96,0,0,113,224,0 1430 DATA 121,176,0,125,252,117,193 1440 DATA 192,127,255,192,113,255,128 1450 DATA 0,252,0,0,24,0,0 1460 DATA 24,0,0,102,0,0,102 1470 DATA 0,0,0,0,0,0,0 1480 DATA 0,0,0,0,0,0,0 1490 DATA 0,0,0,0,0,0,0 1500 DATA 0,0,0,0,0,0,0 1510 DATA 0,0,0,0,0,1,224 1520 DATA 0,1,176,0,127,252,117 1530 DATA 193,192,127,255,192,113,255 1540 DATA 128,0,252,0,0,24,0 1550 DATA 0,24,0,0,102,0,0 1560 DATA 102,0,0,0,0,0,0 1570 DATA 0,0,0,0,0,0,0 1580 DATA 0,0,0,0,0,0,0 1590 DATA 0,0,0,0,0,0,0 1600 DATA 0,0,0,0,0,0,1 1610 DATA 224,0,1,176,112,127,252 1620 DATA 127,221,192,115,185,192,1 1630 DATA 179,128,0,172,0,0,24 1640 DATA 0,0,24,0,0,102,0 1650 DATA 0,102,0,0,0,0,0 1660 DATA 0,0,0,0,0,0,0 1670 DATA 0,0,0,0,0,0,0 1680 DATA 0,0,0,0,0,0,0 1690 DATA 0,0,0,0,96,0,0 1700 DATA 113,224,0,121,176,0,125 1710 DATA 252,117,193,192,127,255,192

	64



Thinking Games			3

1720 1730 1740 1750 1760 1770 1780 1790 1800 1810 1820 1830 1840 1850 1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020 2030 2040 2050 2060 2070 >080 !090 100 110 120 .30 .40 50 60	DATA 113 DATA 0,0 DATA 0,0 DATA 0,0 DATA 0,0 DATA 0,0 DATA 0,0 DATA 0,1 DATA 127 DATA 192 DATA 0,0 DATA 0,0 DATA 0,0 DATA 0,0 DATA 0,0 DATA 0,0 DATA 0,0 DATA 112 DATA 185 DATA 0,0 DATA 0,0 DATA 0,0 DATA 0,0 DATA 0,0 DATA 0,0	255,128,0,252,0,0 0,0,0,0,0 0,0,0,0,0 0,0,0,0,0 0,0,0,0,0 0,0,0,0,0 0,0,0,0,0 224,0,1,176,0 252,117,193,192,127,255 113,255,128,0,252,0 0,0,0,0,0 0,0,0,0,0 0,0,0,0,0 0,0,0,0,0 0,0,0,0,0 0,0,0,0,0 1,224,0,1,176 127,252,127,221,192,115 192,1,179,128,0,172 112,0,0,0,0 0,0,0,0,0 0,0,0,0,0 0,0,0,0,0 0,0,0,0,0 0,0,0,0,0,256
	1=1 READ W$(l):IFW$(l)=^M"THENN=I-l:RETURN 1=1+1:GOTO1980 POKEV,XAND255:POKEV+16,PEEK(V+16)AND2540R-(X> 255):POKE V+l,Y:POKE2040,S IF X=0 THEN POKE V+21,PEEK(V+21)ORl X=X+3:IFX>344 THEN X=0:POKEV+21,PEEK(V+21)AND 254 Y=Y-1+RND(1)2:IFY>100THENY=99 IF Y<50 THEN Y=50 S=S+1:IFS=254THENS=251 RETURN DX=INT(P+13(P>13))16+24+40 DY=173+INT(P/14)*24:IF S>250 THEN S=S-3 POKEV,XAND255:POKEV+16,PEEK(V+16)AND2540R-(X> 255):POKEV+1,Y:POKE2040,S IF X=0 THEN POKE V+21,PEEK(V+21)ORl FLAG=0 IFABS(X-DX)>2THENX=X+3:FLAG=1:IFX>344THENX=0: POKEV+21,PEEK(V+21)AND254 IF Y<DY THEN Y=Y+2:FLAG=1 S=S+1:IFS=251THENS=248 IF FLAG THEN 2090 X=DX:Y=DY

65



	■I Thinking Games

	2170 POKEV,XAND255:POKEV+16,PEEK(V+16)AND2540R-(X> 255):POKEV+1,Y:POKE2040,249 2180 POKE 56334,PEEK(56334)AND254 2190 POKE 1,PEEK(1)AND251 2200 FOR 1=0 TO 7 2210 B=PEEK(53248+8P+I) 2220 FOR J=248 TO 250 2230 POKE J64+40+I3,B 2240 NEXT J,I 2250 POKE l,PEEK(l)OR4 2260 POKE 56334,PEEK(56334)ORl 2270 PRINT"{HOME}{17 DOWN}{8 RIGHT}"; 2280 FOR 1=2 TO 14 2290 PRINTMID$(L$,I,1)"{RIGHT}"; 2300 NEXT 2310 PRINT:PRINT"{DOWN}{8 RIGHT}"; 2320 FOR I=15TO 27 2330 PRINTMID$(L$,1,1)"{RIGHT}"; , 2340 NEXT 2350 DX=160-8LEN(G$):DY=69 2360 POKEV,XAND255:POKEV+16,PEEK(V+16)AND2540R-(X> 255):POKEV+1,Y:POKE2040,S 2370 IF X=0 THEN POKE V+21,PEEK(V+21)ORl 2380 FLAG=0 2390 IFABS(X-DX)>2THENX=X+3:FLAG=1:IFX>344THEN X=0 :POKEV+21,PEEK(V+21)AND254 2400 IF Y>DY THEN Y=Y-2:FLAG=1 2410 S=S+1:IFS=251THENS=248 2420 IF FLAG THEN 2360 2430 X=DX:Y=DY 2440 POKEV,XAND255:POKEV+16,PEEK(V+16)AND2540R-(X> 255):POKEV+1,Y:POKE2040,249 2450 PRINT"{HOME}{4 DOWN}"SPC(18-LEN(G$)); 2460 FOR I=1T0 LEN(G$) 2470 IF MID$(G$,I,1)=A$ THEN PRINT A$;:RF=RF~1:IFR F=0 THEN GOSUB 2560 2480 IF MID$(G$,I,1)<>A$ THEN PRINT"{RIGHT}"; 2490 PRINT"{RIGHT}"; 2500 IF RF=0 THEN 1=100:GOTO2540 2510 FOR J=0 TO 15:X=X+1:S=S+1:IFS=251THENS=248 2520 POKEV,XAND255:POKEV+16,PEEK(V+16)AND2540R-(X> 255):POKE2040,S 2530 NEXT J 2540 NEXT I 2550 RETURN 2560 FOR K=0 TO 7 2570 FOR J=248 TO 250 2580 POKE J64+40+K3,0 2590 NEXT J,K

	66



	Thinking Games	3

	2600 RETURN 2610 PRINT"{CLR}{7 DOWN}{BLK}DO YOU WISH TO PLAY A GAIN (Y/N) ?" 2615 POKE V+21,PEEK(V+21)AND254 2620 PRINT"{10 DOWNJYOU MISSED THIS MANY 2630 GETA$:IFA$<>^,,N"AND A$<>"Y"THEN2630 2640 IF A$="Y"THENPOKE V+21,0:RUN110 2650 END 2660 POKE 53281,0:POKE 53280,0 2670 PRINT" {CLRHYELH 13 SPACES} INSTRUCTIONS 2680 PRINT"{2 DOWN}{WHT}{4 SPACESJCHOOSE LETTERS T O GUESS THE WORD. 2690 PRINT"{DOWN}IF YOU CHOOSE A WRONG LETTER, THE BIRD 2700 PRINT"{DOWN}WILL LAND ON ITS PERCH. 2710 PRINT"{DOWN}{4 SPACESjWHEN ALL THE PERCHES AR E FULL, OR 2720 PRINT"{DOWN}YOU GUESSED THE WORD, THE GAME IS OVER 2730 PRINT"{2 DOWN}{4 SPACESjYOU CAN HIT THE "CHR$ (34)"<-"CHR$(34)" KEY ANYTIME TO 2740 PRINT"{DOWN}GUESS THE WORD. IF YOU GET IT WRO NG,{DOWN}{4 SPACESjYOU LOSE. 2750 PRINT"{3 DOWN}{9 RIGHT}{YEL}HIT A KEY TO BEGI N" 2760 GETA$:IFA$=""THEN2760 2770 RETURN 2780 DATA HAPPY,BRIDGE,FAMILY,CHILDREN 2790 DATA WINDOW,TRAIN,DWARF,BIRDS 2800 DATA SUPERMAN,CONCERT,PEOPLE,MAGIC 2810 DATA SPACE, SCIENCE, PLANETS, GALAXY, STARS 2820 DATA ROOMS, TEACHER, CHALK, BLACKBOARD 2830 DATA SCREEN,COMPUTER,KEYBOARD,PROGRAM 2840 DATA SPELLING,WORDS,COLORS,LETTERS 2850 DATA MARKET, STREETS, SQUARE, TRIANGLE 2860 DATA MOVIE, SPACESHIP, LASER, AIRPLANE, BOAT 2870 DATA STICK,ROCK,PAPER,WIN,PLACE,SHOW 2880 DATA CHANNEL,EXECUTIVE,MONEY,SHIRT 2890 DATA QUIET,LOUD,BILLBOARD,YACHT,MOTORCYCLE,*

	67



	Oil Tycoon Gordon F. Wheat 64 Translation by Chris Metcalf

	You are E J. Uing and you are about to make big money in the petroleum business, but drilling for oil is not as easy as it sounds. There are obstacles you must overcome in order to make a profit. There are shale formations that grind away your pipe. You can blast through them, but your dynamite is limited. Pockets of natural gas sometimes collect where you have previously pumped out the oil. Hit one of these and your oil rig goes up with a bang. There are also "devils" that live in the oil. They take a dim view of your draining their caverns. But you won't give up—because you are the Oil Tycoon. I designed "Oil Tycoon" to be as much fun for parents as it will be for children. Since the game is not based on reaction time but rather on strategy, it helps even the score for the arcade dropouts. Your strategy will slowly build, and before long you will be rolling in cash or attaining high scores, however you wish to look at it. Difficulty Levels The screen will display the high scores attained for each of the eight difficulty levels. The program will return to this screen after each game. Your score and the difficulty level of the game you have just completed are displayed at the top of the screen. At the bottom of the screen you will see "DIFF . LEVEL 12345678." Choose the difficulty level by moving the joystick left and right and pressing the fire button when the number of the difficulty level you want is blinking. Level one is primarily for small children. I would recommend that seasoned gamers begin with level two. The higher the difficulty level, the more difficult the game becomes. The various conditions for the eight difficulty levels are shown in the table.

	68


			Thinking Games
Difficulty Levels	Sticks of
	Dynamite per	Pieces	Invisible
Level	Oil Rig	of Shale	Shale
1	3	20	No
2	2	20	No
3	3	30	No
4	2	30	No
5	4	20	Yes
6	3	20	Yes
7	4	30	Yes
8	3	30	Yes

Playing Oil Tycoon

After you choose the level, the oil field is drawn on the screen. It will be different for each game; you should never see the same screen twice. For each game, you receive five oil rigs, each of which has 20 lengths of pipe and a number of sticks of dynamite, depending on the difficulty level you choose.

In the upper-left corner of the screen are the oil rigs you have remaining. In the upper-right corner is your score. Between these are the sticks of dynamite you have remaining for the oil rig now in play. The second line displays the unused lengths of pipe for the oil rig now in play. As you drill, this pipe will be used one length at a time and will be replaced as you withdraw your drill. The lower portion of the screen is the playing field. Yellow squares are dirt, black squares are oil, and the irregular squares are shale.

Move the joystick left and right to position your oil rig over the column you want to drill through. To drill, pull the joystick down. To withdraw the drill, push the joystick up. You cannot move the oil rig while there is drilling pipe in the ground. You cannot bore through shale, through devils, or off the bottom of the screen. If you try, your drill will be ground up, and you will lose that length of pipe for the oil rig in play. This becomes very important in difficulty levels above four, for the shale is invisible and looks like dirt. At these levels, it is very easy to lose most of your drilling pipe before you realize that you are trying to drill through shale. Also try to avoid drilling through empty spaces from which you have previously pumped oil. Natural gas can collect in these empty spaces and may cause an explosion when yrou try to drill through them again.



	■J Thinking Games Controlling the fire button takes some getting used to, because it does three things. As you bore, if the end of the drilling pipe is in oil or an empty space, pressing the fire button causes your oil rig to start pumping. If the end of the pipe is in dirt, pressing fire drops a stick of dynamite down the pipe. If you are not drilling, or if you have fully withdrawn the pipe, pressing fire replaces your current oil rig with one of your remaining rigs. Be careful—it is easy to lose valuable rigs. Replacing your oil rig with a new one is useful mainly when you have used up your allotted dynamite for the rig in play, or if you do not have enough pipe remaining to reach pools of oil near the bottom of the screen. Use your dynamite to blow up shale, devils, or dirt. When you drop dynamite down the pipe, it will continue to fall until it hits one of these three obstacles. This means that if there is oil or empty space directly below the tip of the drill, the dynamite will fall out of the bottom of the pipe and through this space until it hits shale, a devil, or dirt. Pumping Oil When you pump, all of the oil in adjacent spaces to the sides and above the level of the drill bit will be pumped out. In other words, all squares of oil connected to the one you are pumping will also be pumped out only if they lie directly above or to the sides of the oil being pumped. Any squares of oil below those which are being pumped out will remain where they are. If you uncover a devil while pumping, it will blow up your oil rig. If you try to pump a pool of oil which is at or below the level of an uncovered devil, and which is directly connected to the devil's space, it will also blow up your rig. The deeper the oil, the more it is worth when you pump it out. An extra oil rig is awarded for each $100,000 you acquire. In addition, if you pump out all the oil on the screen and then retract your pipe, you will be awarded an extra oil rig and a new screen is drawn. Oil Tycoon 100 PRINT"{CLR}g73":IFPEEK(14336)=2ANDPEEK(14805 )=24THEN195 105 POKE53280,6:POKE53281,6:POKE53270,8 110 PRINTTAB(14)"INSTRUCTIONS"SPC(28)"gl2 T3":PR INT"{DOWN}JOYSTICK:" 115 PRINT"{DOWN} RIGHT AND LEFT = MOVE RIG" 120 PRINT" DOWN = DRILL"xPRINT" UP = RETRACT PIPE"

	70



	Thinking Games	3

	125 PRINT"{2 DOWN}{2 SPACES}WHEN YOU PUSH THE FIRE BUTTON AND THE 130 PRINT"PIPE IS DOWN IN OIL OR IN SPACE, THE" 135 PRINT"PUMP IS TRIGGERED.{2 SPACESjlF THE PIPE {SPACE}IS DOWN" 140 PRINT"IN DIRT, DYNAMITE IS DROPPED. 145 PRINT"{2 DOWNJWATCH OUT FOR SHALE AND GAS IN E MPTY","SPACES AND DEVILS IN OIL. 150 PRINT"{2 DOWN}PLEASE {CYN}WAITg7§ FOR FURTHE R INSTRUCTIONS." 155 POKE52,56:POKE56,56:CLR:AD=14336 160 FORA=ADTOAD+207:READB:POKEA,B:NEXT:POKE56334,P EEK(56334)AND254:POKEl,51 165 FORA=AD+256TOAD+471:POKEA,PEEK(38912+A):NEXT:P 0KE1,55 170 POKE56334,PEEK(56334)ORl 175 PRINT"{UP}{2 SPACESjPRESS ANY KEY WHEN READY T O BEGIN. " , 180 IFPEEK(197)=64ANDPEEK(653)=0ANDPEEK(56320)=127 THEN180

	195 PRINT"{CLR}":POKE53280,6:POKE54296,15:DIMA%(40 ):W=1184:JS=56320 200 POKE53282,6:POKE53283,0:POKE53270,24:POKE54291 ,0:POKE54292,240 205 FORI=0TO2:POKE54276+I7,8:NEXT:POKE53281,3 210 POKE54284,0:POKE54285,240:POKE54277,0:POKE5427 8,240:IFZ > B%(T)THENB%(T)=Z 215 P0KE53272,21:PRINT"{CLRHD0WN}{RED}^m,T_/ " {2 SPACES}$"MID$(STR$(Z100),2)".00{BLU}" 220 PRINTTAB(8)"{DOWN} LEVEL{6 SPACES}HIGH SCORE {DOWN}" 225 F0RA=1T08:PRINT_#A_#"{2 SPACES}$"MID$(STR$(B%(A) *100),2)".00":PRINT:NEXT 230 PRINT"{DOWN} DIFFICULTY LEVEL? 12345678{GRN}": T=l 235 POKE56194+T,0:Tl=T:T=T+(PEEK(JS)AND4)/4-(PEEK( JS)AND8)/8:T=(7ANDT-1)+1 240 IFT<>T1THENP0KE56194+T1,6 245 POKE56194+T,l:L=3:IFT/2=INT(T/2)THENL=2 250 S=20:IFT=3ORT=4ORT>6THENS=30 >55 N=24:IFT>4THENN=25:L=L+1 !60 GETA$:IF(PEEK(56320)AND16)=16ANDA$<>CHR$(13)TH EN235 65 POKE53272_#31:PRINT"{CLR}":POKE53280,9:POKE5328 1,1:M=4:Z=0:K=0:GOSUB590 70 POKEW+X_/14:X=20:P=20:Y=L:R=1:GOSUB705:GOSUB645 :POKE198_#0

	71



	■^ Thinking Games

	275 : 280 : 285 REM MAIN LOOP OF PROGRAM 290 A=PEEK(JS):IF(AAND4)=0ANDR=1THENPOKEW+X,14:X=X +(X>0) 295 IF(AAND8)=0ANDR=1THENPOKEW+X,14:X=X-(X<39) 300 POKEW+X,2:IF(AAND2)=0ANDP>0THEN340 305 IF(AAND1)=0ANDR>1THEN400 310 IFR>1AND(AAND16)=0THEN435 315 IFR=1AND(AAND16)=0 THEN375 320 GOTO290 325 : 330 : 335 REM DRILLING AND GAS EXPLOSIONS 340 A=R40+W+X:C=PEEK(A):P=P-1:GOSUB675 345 IFC=NORC=3ORA>2023THENFORA=1TO3:GOSUB730:NEXT: GOTO290 350 IFRND(1)>.06ORC<>14THENFORB=1TO3:POKEA,C+B:GOS UB7 30:NEXT:R=R+1:GOTO290 355 FORB=lT02:POKEA,C+B:GOSUB730:NEXT:GOSUB735:B=0 360 R=R-1:POKE54296,4:IFR<1THENPOKE54296,15:POKEW+ X,23:GOSUB715:GOT0375 365 POKE54273,B:POKE54276,129:A=R40+W+X:C=PEEK(A) :PK=PEEK(A+54272):POKEA,C+l 370 POKEA+54272,15:FORD=0TO200:NEXT:POKEA_#C-3:POKE A+54272,PK:B=B+10:GOTO360 375 POKEW+X,14:X=20:M=M-1:P=20:Y=L:R=1:GOSUB705:IF M<0THEN205 380 GOSUB645:GOTO290 385 : 390 : 395 REM DRILLING UP 400 R=R-1:B=R40+W+X:C=PEEK(B):F0RA=1T03:POKEB,C-A :GOSUB730:NEXT 405 P=P+1:GOSUB675:IFR<>1THEN290 410 FORA=W+80TO2023:IFPEEK(A)=9THEN290 415 NEXT:M=M+1:FORC=lT03:GOSUB705:NEXT:GOSUB590:GO SUB645:GOTO290 420 : 425 : 430 REM DYNAMITE, GUSHERS, DEVILS 435 J=Z:Q=R-l:FORA=0TO21:A%(A)=0:NEXTzB=Q40+W+X:A =PEEK(B):IFA<>7THEN480 440 A=W+X:B=40:IFY<1THEN290 445 A=A+40:C=PEEK(A):POKEA,C+l:IFC=140RC=9THENPOKE A,C+4 450 POKE54273,B:POKE54276,33:FORD=0TO200:NEXT:D=PI EK(A+40) 455 IFD<>4ANDD<>NANDD<>3ANDA<1984THENB=B-2:POKEA,' :GOT0445

	72



	Thinking Games	3

	460 POKE54276,8:GOSUB735:POKEA+54312,15 465 IFC<>14ANDC<>9THENR=R-1 470 Y=Y-l2GOSUB665:GOTO290 475 : 480 A%(X)=1:POKE54273,40:POKE54276,129:POKE54296,4 :V=W+X-40 485 IFA=12THENPOKEB,17:Z=Z+Q:POKEV,0 490 E=0:F=38:D=l:G=l2l=l:GOSUB530 2POKEV_#l:E=39:F=l :D=-1:G=D:I=D:GOSUB530 495 E=0:F=39:D=1:G=-40:I=0:GOSUB530:POKEV,0:IFC<>6 THEN515 500 Z=J:POKEB,3:POKEB+54272,2zPOKEV,14 2 FORA=0TO40 2 POKE54280,88 2 POKE54283,17 505 POKE53283,14 2 POKE54296,6 2 F0RB=1T05 2NEXT 510 POKE54296,0 2 POKE53283,0 2 F0RB=1T05 2NEXTB,A2 POKE 54283,0 2 B=0 2 GOTO360 515 IFHTHENQ=Q-12 GOT04 90 520 POKEV,14 2 POKE54276 ,8:POKE54296,15 2POKE54283,2: GOSUB705 2 GOSUB645 2 GOTO290 525 2 530 IFC=6THENRETURN 535 H=0 2FORA=ETOFSTEPD2lFA%(A)=0THEN570 540 B=Q40+W+A+G2C=PEEK(B) 545 IFC=90RC=12THENPOKEB_/C+5 2H=12 Z=Z+Q+ABS(I)-l2A% (A+l)=l2GOT0565 550 IFC=14ORC=17THENA%(A+l)=l2H=l2GOTO570 555 IFC=3THENC=62 RETURN 560 A%(A+I)=0 2GOTO570 565 IFRND(1)<.02ANDC<>12THENC=6 2RETURN 570 NEXT 2 RETURN 575 2 580 2 585 REM INITIALIZE THE DISPLAY 590 PRINT"{HOME}{5 DOWN}§83";_:F0RA=1T099:PRINT^MD DDDDDDD";2 NEXT 2 PRINT"DDDDDDD"; 595 POKE2023,4:POKE56295,15 2 B=400 2 C=1264 2 F0RA=1T02 2FORD=1TO40 600 E=INT(RND(0)B/2)2+C2lFPEEK(E)=9ORPEEK(E+l)=9 THEN600 505 POKEE,9 2 POKEE+1,9 2 NEXT 2 B=360 2 C=1665 2 NEXT 2 FORA= 1TOS S10 B=INT(RND(1)340)*2 + 1264 2 C=PEEK(B)2IFC=90RC=NT HEN610 .15 POKEB,N2POKEB+54272,10 2NEXT2FORA=0TO1992POKE55 296+A,0 2NEXT 2 FORA=0TO39 20 POKE55376+A,3 2POKE1104+A,20 2NEXT 25 FORA=0TO3 2 POKE55337+A,2 2NEXT2 RETURN 30 2 35 2

	73



	■C Thinking Games

	640 REM UPDATE SCREEN INFORMATION 645 PRINT"{HOME}{GRN}"SPC(23)"$"MID$(STR$(Z*100),2 )" .00" 650 A=INT(Z/1000):IFA=K+1THENK=K+1:GOSUB705:GOSUB7 05:M=M+1 655 IFM<1THENPOKE1024,14:POKE55296,14:GOTO665 660 FORA=1024TO1023+M:POKEA,2:POKEA+54272,0:NEXT:P OKEA,14:POKEA+54272,0 665 IFY=0THENPOKE1031,14:POKE55303,0:GOT0675 670 FORA=1031TO1030+Y:POKEA,19:POKEA+54272,0:NEXT: POKEA,14:POKEA+54272 , 0 675 IFP<1THENPOKE1064,14:POKE55336,0:RETURN 680 FORB=1064TO1063+P:POKEB,17:POKEB+54272,0:NEXT: POKEB,14:POKEB+54272,0 685 RETURN 690 : 695 : 700 REM MUSIC AND OTHER SUBROUTINES 705 POKE54276,17:FORA=15TO0STEP-1:POKE54296,A:POKE 54273,86:FORB=lT025:NEXTB,A 710 POKE54276,8:POKE54296,15:RETURN 715 POKE54276,8:POKE54276,129:POKE54273,91:FORD=15 TO0STEP-1:POKE54296, D 720 POKE53281,1:POKE53280,2:FORE=1TO70:NEXT:POKE53 280,6:NEXT 725 POKE54276,8:POKE54296,15:POKE53280,9:RETURN 730 POKE54287,20:POKE54290,8:POKE54290,129:POKE542 90,128:RETURN 735 POKEA,21:POKEA+40,22:GOSUB715:POKEA,14:POKEA+4 0,14:RETURN 740 : 745 : 750 REM CHARACTER DATA 755 DATA2,138,164,73,74,52,20,8,64,81,37,146,82,44 ,40,16,24,24,36 760 DATA60,90,102,231,153,20,42,42,20,62,73,20,20, 136,34,136,34,136,34,136,34 765 DATA148,22,148,34,136,34,136,34,148,22,148,22, 148,34,136,34,148,22,148 770 DATA22,148,22,148,22,136,62,188,62,188,62,188, 22,170,170,170,170,170 775 DATA170,170,170,150,150,150,170,170,170,170,17 0,150,150,150,150,150,170,170 780 DATA170,150,150,150,150,150,150,150,150,150,IS 0,190,190,190,190,190,150,0,0 785 DATA0,0,0,0,0,0,20,20,20,0,0,0,0,0,20,20,20,21 ,20,0,0,0,20,20,20,20,20,20 790 DATA20,20,20,60,60,60,60,60,60,20,0,60,60,60,- 0,60, 60,0., 0,0, 0,255, 255, 0,0,0

	74



	Thinking Games	3

	795 DATA218,118,181,153,110,93,197,65,65,82,150,85 ,121,181,150,173,2,106,129,20 800 DATA64,162,129,2,169,128,141,19,145,169,0,133, 136,34,136,34,136,34,136,34

	75



	Mosaic Puzzle Bruce Jordan 64 Translation by Chris Metcalf_________

	77ns adaptation of an old favorite will challenge your reasoning powers. "Mosaic Puzzle" is a computer version of those sliding-squares puzzles that used to drive people nuts before the advent of Rubik's Cube. The object of the game is to arrange the 15 squares into some predetermined order by sliding them around in their frame. The first few moves are easy, but as the game progresses, it gets a lot more complicated. You'll find yourself rearranging everything just to get the last few squares in place. The game has a timer for up to 23 hours, 59 minutes, 59 seconds, and a chicken switch. It also automatically checks for the winning order and allows you to go back to the puzzle the way you left it or reset it to the beginning arrangement. When you start the game, you're asked if you wish to set a time limit. If you answer Y for yes, enter the time limit in one line with no spaces or punctuation between the values. For example, for a 1-hour, 23-minute limit, enter 012300. Next, enter the goal order. This will be the order that you will try to match to win the game. When this is done, the upper half of the screen will clear, and the puzzle will appear. Either the RETURN key or the fire button allows you to pause momentarily before resuming the game, restarting the program, or stopping play entirely. Breaking off and resuming has no effect on the time clock (displayed at the top of the screen along with the time limit). As an aid to the user, various keys for up, down, right, and left can be selected at the beginning of the game. A joystick can also be used, as long as it is plugged into control port two. The time limit is an option in this version; if no time limit is selected, the screen will display elapsed time and TIME LIMIT: NONE. If you succeed in getting the squares in the goal order, the message YOU WIN! appears on the screen, accompanied by a short tune and the elapsed time. If the time runs out before you are finished, you'll hear an unpleasant sound.

	76



	Thinking Games	3

	Mosaic Puzzle 100 POKE53280,14:POKE53281,6:POKE55,176:POKE56_/29: CLR:POKE54276,8:POKE54283 , 8 110 POKE54277,0:POKE54278,255:POKE54284,0:POKE5428 5,255:POKE54296,15 120 S=1355:SC=S+54272:DIMA$(16) 130 PRINT"{CLR}":G=1632:X=0:DX=1:P=55904:S1=54276: S2=54283:AD=1232:R=14 140 PRINT"{CLR}{DOWN}"TAB(11)" MOSAIC PUZZLE"TAB(5 0)"§17 Y5){DOWN}" 150 : 160 : 170 REM FIND TIME LIMIT, MOVE KEYS 180 PRINT"i73 DO YOU WANT A TIME LIMIT? ";:GOSUB 270 190 IFIN$<>"Y"THEN240 200 H=l:INPUT"{HOME}{6 DOWN} HOURS MINS SECS (6 DI GITS)";T$:IFLEN(T$)<> 6THEN200 210 IFLEFT$(T$,2)>"23"ORLEFT$(T$,2)<"0"THEN200 220 IFMID$(T$,3,2)>"59"ORMID$(T$,3,2)<"0"THEN200 230 IFRIGHT$(T$,2)>"59"ORRIGHT$(T$,2)<"0"THEN200 240 PRINT"{DOWN} KEY FOR UP: ";:GOSUB270:U$=IN$:PR INT"{DOWN} FOR DOWN: ";:GOSUB270:D$=IN$ 250 PRINT"{DOWN} FOR LEFT: ";:GOSUB270:L$=IN$:PRIN T"{DOWN} FOR RIGHT: ";:GOSUB270:R$=IN$ 260 GOTO310 270 PRINT"g+3";:WAIT198,255:GETIN$:PRINT"{LEFT}" ;:POKE216,1:PRINTIN?:RETURN 280 : 290 : 300 REM FIND GOAL ORDER 310 PRINT"{CLR}"TAB(43)"ENTER GOAL SETUP" 320 PRINT"{DOWN}{3 SPACES}1 2 3 4 5 6 7 8 9"SPC(23 )"A B C D E F {RVS}SPACE" 330 PRINTTAB(5)"{D0WN}IN ANY ORDER":PRINTTAB(248)" GOAL 340 FORK=0TO3:POKE1592+K,100:POKE1792+K,99:POKE558 64+K,R:POKE56064+K,R 50 POKE1631+K40,103:POKE1636+K40,101:POKE55903+ K40,R:POKE55908+K40,R:NEXT 160 F0RI=1T016:POKEG+X,63:POKEP+X,1 70 WAIT198,255:GETA$(I):FORL=I-1TO0STEP-1:IFA$(I) =A$(L)THEN370 80 NEXT:IFA$(I)=" "THENFORK=0TO4:POKE55471+K,15:N EXT:B2=32:GOTO420 90 IF(A$(I)<"l"ORA$(I)>"F")OR(A$(I)>"9"ANDA$(I)<^,, A")THEN370 50 B=VAL(A$(I)) :B2=B+48:IFBTHENPOKE55417-f2B,15:G OTO420

	77



	■i Thinking Games

	410 B=ASC(A?(l))-64:B2=B:POKE55457+2B,15 420 POKEG+X,B2:X=X+DX:IFX=4THENG=G+40:P=P+40:X=0 430 NEXT 440 : 450 : 460 REM SET UP WORK AREA 470 PRINT"{HOME}":FORI=0TO64:PRINT"{4 SPACES}";:NE XT:PRINT"{HOME}"TAB(127)"PUZZLE" 480 FORK=0TO3:POKE1192+K,100:POKE55464+K,R:POKE139 2+K,99:POKE55664+K,R 490 POKE1231+K40,103:POKE55503+K40,R:POKE1236+K 40,101:POKE55508+K*40,R:NEXT 500 READA,B,C:IFA>=0THENPOKEAD+A,B?POKE55504+A,C:G OTO500 510 FORI=1TO500:NEXT:POKES1-3,80:POKES1,33:PRINT" {HOME}"TAB(28)"{10 DOWN}{RED}{WHT}IGO!§73" 520 FORT=1TO300:NEXT:PRINT"{HOME}"TAB(28)" {10 DOWN}{4 SPACES}":POKESl,8:TI?="000000" 530 PRINT"{HOME}"TAB(25)"LIMIT:{CYN}";:IFT$=""THEN PRINT"NONE":GOTO580 540 PRINTLEFT?(T?,2)":"MID?(T$,3,2)":"RIGHT?(T?,2) "g7i" 550 : 560 : 570 REM LOOP MAIN CONTROL 580 PRINT"{HOME}TIME ELAPSED:{WHT}"LEFT?(TI?,2)":" MID?(TI?,3,2)":"RIGHT?(TI?,2)"g 7 3" 590 IFH=1ANDT?<=TI?THEN750 600 GETB?:J=31-PEEK(56320)AND31:IFB?=""ANDJ=0THEN5 80 610 IFB?=CHR?(13)ORJ=16THENWN=0:GOTO780 620 IFB?=D?OR(JAND2)THENDR=~40:CK=100:GOTO660 630 IFB?=L?OR(JAND4)THENDR=1:CK=101:GOTO660 640 IFB?=R?OR(JAND8)THENDR=-1:CK=103:GOTO660 650 DR=40:CK=99:IFB? < >U?AND(JAND1)=0THEN580 660 IFPEEK(S+DR)=CKTHEN580 670 POKES,PEEK(S+DR)^OKESC,PEEK(SC+DR):POKES+DR,3 2:S=S+DR:SC=SC+DR 680 FORM=0TO120STEP40:FORN=0TO3:W=PEEK(AD+M+N)AND1 27:IFW< > PEEK(1632+M+N)THEN580 690 NEXT:NEXT:PRINT"{HOME}"TAB(24)"{5 DOWN}{CYN} {RVS}YOU WINi g7i":POKES1-3,0:POKES1,33:WN=1 700 READN1,N2,D:IFN1=-1THENP0KES1,8:GOTO780 710 POKES1-4, Nl: POKES1-3 , N2 : FORT=lTOD: NEXT: GOTO70I2 720 : 730 : 740 REM END OF GAME 750 PRINT"{HOME}"TAB(23)"{5 DOWN}{WHT}{RVS}1 YOU L SElg73":POKESl-3_f10:POKES1_#17:WN=1

	78



	Thinking Games

	760 POKES2-3,60:POKES2,129:FORT=1TO300:NEXT:P0KES2 ,8:P0KES1,8 770 : 780 TM$=TI$:PRINT"{HOME}"TAB(21)"{9 D0WN}(1) RESET 790 PRINTTAB(21)"{DOWN}(2) QUIT":IFWN=0THENPRINTTA B(21)"{DOWN}(3) AS YOU LEFT IT" 800 GETV$:IFV$ <"1"ORV$ >"3"THEN800 810 IFV$="1"THENRUN 820 IFV$="2"THENEND 830 IFWNTHEN800 840 PRINT"{HOME}{8 DOWN}":FORI=1T06:PRINTTAB(21)" {18 SPACES}":NEXT 850 TI$=TM$:GOTO580 860 : 870 : 880 REM SETUP AND MUSIC DATA 890 DATA0,49,1,1,178,3,2,51,1,3,180,3 900 DATA40,53,1,41,182,3,42,55,1,43 910 DATA184,3,80,57,1,81,129,3,82,2,1 920 DATA83,131,3,120,4,1,121,133,3,122 930 DATA6,1,123,32,3,-1,-1,-1 940 DATA 96,22,150,0,0,50,96,22,75,0,0,50,96,22,75 ,49,28,175,96,22,115,49,28 950 DATA175,135,33,250,0,0,0,-1,-1,-1

	79



	4 Blockhead_______ Matt Giwer 64 Version by Gregg Peele______________________________

	Here is a challenging game for the whole family. See how many balloons the blockhead can pop in the allotted time. Requires game paddles. "Blockhead" is a colorful game similar to some of the early arcade games. It is simple to play, and will especially appeal to young children, who will like the clever use of sound and color in the game. The program makes good use of the Commodore 64's graphic capabilities, for it utilizes the eight available sprites and even includes a machine language routine. This interrupt-driven routine provides optimal motion in the game, as well as monitors the position of the sprites. Once you have the program typed in, SAVEd, and LOADed, you can see that the machine language routine still operates, even if the BASIC part of the program does not. LOAD and RUN Blockhead, then press RUN-STOE This breaks the BASIC program, but the blockhead can still be moved with the paddle control. Blockhead uses the collision register to detect when one sprite touches another. Since the collision register is changed only temporarily when sprites collide, the contents representing the collision must be saved until an event occurs which may again make the sprite collide. The register is then cleared, and the sprite is ready for collision. Collision detection between the blockhead and balloons is handled through BASIC. The game is played with a set of paddles, which must be plugged into Control Port 1. Since Blockhead is a one-player game, only one paddle will work. The paddle moves the blockhead's home base from side to side, with the blockhead standing on it. You use the fire button on the paddle to make the blockhead leap. The original version of this game is written to be used with Atari-style paddles. If you have Commodore paddles, you must change lines 1070 and 1080 to read as follows: 1070 DATA 216,24,173,164,194,105,28,141 1080 DATA 161,194,56,173,164,194,233,217

	83



	This alteration leaves a slight glitch in the paddle movement around the seam but provides for optimal range for movement around the screen. Playing the Game This game works using a timer. The object of the game is to pop the balloons as they float across the sky. The more balloons you pop in the time limit of two minutes, the more points you'll receive. Not only must you pop the balloons, but you must also catch the blockhead before he falls below his home base. If you miss catching him, points are deducted until you bring him to the surface by pressing the fire button. He'll then leap back into the air. For each balloon that you pop, you receive 10 points. Each time you drop the blockhead, your score is reduced by 15 points. When you LOAD and RUN the program for Blockhead, a tune plays and the screen sets up. This takes a few moments, so be patient. Finally, the blockhead appears, and the balloons begin to float across the sky At first, they are close to the ground and easy to pop. Simply press the fire button and the blockhead leaps into the air. If he touches a balloon, it disappears, and you'll hear a soft popping sound. You've just received ten points. The balloons will continue to float at this level until all six of them are popped by the blockhead. As soon as the first level of balloons has been popped, the tune plays again, then another level, slightly higher, appears from the left side of the screen. There are six levels of balloons altogether. If you pop all the balloons, 36 in all, the game stops, even if there is time remaining. At this point, you're asked if you want to play another game. Of course, popping the balloons is only half the fun. You also have to catch the blockhead as he drops to the ground. If you miss him with the paddle-controlled base, he will vanish. To make him reappear, you need to press the fire button to make him leap back up. Going for the High Score After playing Blockhead a few times, you'll notice some things that can increase your score, or reduce the time it takes you to pop all the balloons. If you time the blockhead's leap, you can pop two balloons at once. This must be precise. The blockhead has his hands out-

	84



	Dexterity

	stretched, and if both come in contact with a balloon at the same time, the balloon on either side will pop. Sometimes this works, and other times it doesn't. You can also receive points if the blockhead comes very close to a balloon. The balloon won't pop, but you'll hear the popping sound, and another ten points will be added to your score. Just as with trying to pop two balloons at once, this will not work all the time. If you keep the blockhead's home base stationary, most of the time he will fall back to it. Not always, so you have to keep your eye on him. Remember that the blockhead is not able to pop a balloon on the way down, only on the way up. Blockhead 100 POKE49152,0 110 DIM HA(12),HB(12)_/HC(12),LA(12),LB(12),LC(12) 120 F0RQ=1T011:READHA(Q),LA(Q),HB(Q),LB(Q),HC(Q),L C(Q):NEXT 130 S=54272:FORE=STOS+28:POKEE,0:NEXT 140 POKE54296,15 :POKE54277,56 :POKE54278,212 150 POKE54284,56 -.POKE54286 , 212 160 POKE54291,56 :POKE54292,212 170 POKE S+4,17:POKES+16,17:POKES+18,17 180 F0RD=1T011 190 POKES+l,HA(D):P0KES,LA(D):POKES+8,HB(D) 200 POKES+9,LB(D):POKES+15,HC(D):P0KES+14,LC(D) 210 FORT=1TO100:NEXT 220 IFHC(D) =7THENFORT=1TO100:NEXT 230 NEXT 240 F0RT=1T0 450 :NEXT:FORE=ST0S+28:POKEE,0:NEXT 250 IFPEEK(49152)=173ANDTH=1THENRETURN 260 DATA33,135,21,31,8,97,31,165,21,31,8,225,29,22 3,22,96,9,104 270 DATA 28 ,49,22,96,9,247,26,156,21,31,10,143 280 DATA28,49,21,31,9,247,29,223,22,96,9,104,31,16 5,22,96,8,225 290 DATA33,135,21,31,8,97,25,30,22,96,7,233,33,135 ,21,31,8,97 300 GOTO330 310 S=54272 320 POKES+24,15:POKE54276,65:POKE54275,10:POKE5427 4,10:POKES+24,0:RETURN 330 POKE53281,7:HI=134:GOSUB930 340 DATA1,255,0,7,255,192,15,239,224,31,1,240,63,1 09,248,63,111,248,63,1,248,63

	85



	350 DATA237,248,63,109,248,31,1,240,31,239,240,15, 239,224,15,255,224,7,255,192,3 360 DATA255,128,1,255,0,0,254,0,0,124,0,0,56,0,0,1 6,0,0,56,0 370 V=53248 380 FOR J=960TO1022:READ WQ:POKE J,WQ:NEXT 390 POKEV+21,0 400 POKEV+41,6:POKEV+42,0:POKEV+43,1:POKEV+44,2:PO KEV+4,70 410 POKE53264,0 420 POKEV+45,4:POKEV+46,8 430 FORT=2042TO2047:POKET,15:NEXT:POKEV+21,255 440 IFPEEK(V+2)<50AND(PEEK(V+16)AND2)=0THENPOKEV+2 ,254 450 DATA0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,255,255,255,255,255 460 DATA255,255,255,255,255,255,255,255,255,255,25 5,255,255,255,255,255,255,255 470 DATA255,255,255,255,255,255,255,255,255,255 480 V=53248 490 FORI=832T0894:READJ:POKEI,J:NEXT 500 FORK=834+64T0892+66:READL:POKEK,L:NEXT:POKE204 l,14:POKEV+40,6 510 POKE2040,13:POKEV+39,2:POKEV,150:POKEV+1,200 520 IFPEEK(49152)<>173THENGOSUB1050 530 POKEV+3,191 540 IFHK70THENHI = 59 550 TH=1:GOSUB130 560 POKEV+2,PEEK(V):POKEV+21,255 570 FORG=V+5TO V+15STEP2:POKEG,HI:NEXT 580 SYS49658 590 DATA0 600 DATA0,0,0,0,0,0,3,255,240,3,63,48,3,51,48,3,24 3,240,3,63,48,3,204,240,3,243 610 DATA240,3,255,240,0,127,128,127,243,255,127,25 5,255,255,255,255,128,115 620 DATA128,0,127,128,0,127,128,0,251,192,1,241,22 4,3,224,240,7,192,120 630 IF(PEEK(56321)AND4)<>0THEN790 640 X2=0:POKE49829,0 650 FORT=(PEEK(V+3))TO50STEP-4:POKEV+3,T 660 IFPEEK(V+30)>3THENPOKEV+21,(PEEK(V+21)ANDNOT(P EEK(V+30))):SC=SC+10:GOSUB310 670 POKE(V+21),(PEEK(V+21)OR3) 680 NEXT:GOTO700 690 GOTO790 700 POKE49829,0 710 FORJ=(PEEK(V+3))T0255STEP20:POKEV+3,J:IFPEEK(4 9829)=3THENX2=1:GOTO790

	86



	Dexterity	4

	720 PI=INT(RND(0)20)-10:IF(PEEK(53250)+Pl)<60AND( PEEK(53264)AND2)=0THENPI=0 730 IF(PEEK(V+2)+Pl)<50AND(PEEK(V+16)AND2)=0ORPEEK (V+2)>254THENPI=0 740 IF(PEEK(53264)AND2)<>0AND(PEEK(53250)+Pl)>20TH ENPI=0 750 IF PEEK(53250)+PK245AND PEEK( 53250 )+PI>10THEN* POKE53250,PEEK(53250)+PI 760 IFPEEK(V+3)<201THEN780 770 PRINT"{HOME}{3 DOWN}{7 RIGHT}{BLK}OOPSl":SC=SC -5:FORT=1TO100:NEXT:PRINT"{HOME}{7 RIGHT} {3 DOWN}{5 SPACES}" 780 NEXT 790 IF PEEK(V+21)=3THEN:HI=HI-15:POKEV+3,190:GOTO5 30 800 IFX2=lANDPEEK(V+3)>180THENPOKEV+3,190 810 P=INT(RND(0)*20)-10:IFPEEK(53250)+P<15THENP=0 820 PRINT"{HOME}{15 RIGHT}{BLK}SCORE";"{5 SPACES}" 830 PRINT"{HOME}{15 RIGHT}{BLK}SCORE";SC 840 IFVAL(TI$)>5900THENTI$="000000" 850 IFTI$>="000200"THEN870 860 PRINT"{HOME}{DOWN}{3 RIGHT}TIME ";RIGHT?(TI$,4 );"{HOME}{DOWN}{3 RIGHT}TIME ";:GOTO630 870 PRINT"{HOME}{15 RIGHT}{8 DOWN}GAME OVER":POKEl 98,0 880 PRINT"{HOME}{DOWN}{3 RIGHT}TIME ";RIGHT$(TI$,4 );"{HOME}{DOWN}{3 RIGHTjTIME "; 890 PRINT"{HOME}{10 RIGHT}{10 DOWNjPLAY AGAIN? Y O R N " 900 IFPEEK(197)=25THENCLR:RESTORE:GOTO110 910 IFPEEK(197)=39THENSYS2048 920 GOTO890 930 PRINT"{CLR}";:FORBO=1024TO1984STEP40:POKEBO,22 4:POKEBO+39,224 940 POKEBO+54272,2:POKEBO+54311,2 950 POKEBO+l,224:POKEBO+38,224 960 POKEBO+1+54272,4:POKEBO+54310,4 970 POKEBO+2,224:POKEBO+37,224 980 POKEBO+2+54272,15:POKEBO+54309,15 990 NEXT 1000 FORFL=1864TO2023:POKEFL,224:POKEFL+54272,8:NE XT 1010 TI$="235952" 1020 FORTE=1025TO1062:POKETE,224:POKETE+54272,3:NE XT 1030 POKE53280,1 1040 RETURN

	87



1050 1051 1052 1060 1070 1080 1090 1100 1110 1120 1130 1140 1150 1160 1170 1180 1190 1200 1210 1220 1230 1240 1250 1260 1270 1280 1290 1300 1310 1320 1330 1340 1350 1360 1370 1380 1390 1400 1410 1420 1430 1440 1450 1460 1470 1480 1490	POKEV+21,0:F0RV1=4915 2T0496 7 3:READJ2:P0KEV1,J 2:CK=CK+J2:NEXT IF CKO65960 THEN PRINT "DATA ERROR IN LINES {SPACE}1060-1710":STOP RETURN DATA 173, 25, 212, 73, 255, 141, 164, 194
	DATA 216, 24, 173 DATA 161, 194, 56	164, 194, 105, 40, 141 173, 164, 194, 233, 215
	DATA 141, 162, 194, 173, 164, 194, 201, 216
	DATA 176, 17, 173 DATA 173, 16, 208 DATA 76, 65, 192, DATA 141, 16, 208 DATA 194, 173, 16 DATA 30, 208, 141 DATA 165, 194, 17 DATA 23, 169, 190 DATA 208, 173, 16 DATA 202, 10, 13, DATA 173, 16, 202 DATA 202, 173, 16 DATA 18, 202, 173 DATA 17, 173, 16, DATA 208, 173, 18	161, 194, 141, 163, 194 41, 254, 141, 16, 208 173, 16, 208, 9, 1 173, 162, 194, 141, 163 , 194, 141, 0, 208, 173 160, 194, 240, 3, 141 , 160, 194, 41, 1, 240 173, 163, 194, 141, 2 208, 41, 1, 141, 6 6, 202, 141, 16, 208 56, 233, 210, 141, 17 202, 24, 105, 45, 141 16, 202, 201, 210, 176 208, 41, 251, 141, 16 202, 141, 4, 208, 76
	DATA 168, 192, 173, 16, 208, 9, 4, 141
	DATA 16, 208, 173 DATA 173, 19, 202 DATA 202, 173, 19 DATA 21, 202, 173 DATA 17, 173, 16, DATA 208, 173, 21	17, 202, 141, 4, 208 56, 233, 210, 141, 20 202, 24, 105, 45, 141 19, 202, 201, 210, 176 208, 41, 247, 141, 16 202, 141, 6, 208, 76
	DATA 224, 192, 173, 16, 208, 9, 8, 141
	DATA 16, 208, 173 DATA 173, 22, 202 DATA 202, 173, 22 DATA 24, 202, 173 DATA 17, 173, 16, DATA 208, 173, 24 DATA 24, 193, 173 DATA 16, 208, 173 DATA 173, 25, 202 DATA 202, 173, 25 DATA 27, 202, 173 DATA 17, 173, 16, DATA 208, 173, 27 DATA 80, 193, 173 DATA 16, 208, 173 DATA 173, 28, 202 DATA 202, 173, 28	20, 202, 141, 6, 208 56, 233, 210, 141, 23 202, 24, 105, 45, 141 22, 202, 201, 210, 176 208, 41, 239, 141, 16 202, 141, 8, 208, 76 16, 208, 9, 16, 141 23, 202, 141, 8, 208 56, 233, 210, 141, 26 202, 24, 105, 45, 141 25, 202, 201, 210, 176 208, 41, 223, 141, 16 202, 141, 10, 208, 76 16, 208, 9, 32, 141 26, 202, 141, 10, 208 56, 233, 210, 141, 29 202, 24, 105, 45, 141

Dexterity


1500	DATA	30,	202,	173,	28,	202,	201,	210	, 176
1510	DATA	17,	173,	16,	208,	41,	191,	141,	16
1520	DATA	208,	173,	30,	202,	141	, 12,	208	p 76
1530	DATA	136,	193	173	, 16	208	, 9,	64, .	L41
1540	DATA	16,	208,	173,	29,	202,	141	p 12,	208
1550	DATA	173	31,	202,	56,	233,	210	141	r 32
1560	DATA	202,	173	p 31,	202	, 24,	105	p 45,	141
1570	DATA	33,	202,	173,	31,	202,	201	, 210	, 176
1580	DATA	17,	173,	16,	208,	41,	127,	141,	16
1590	DATA	208	, 173	p 33,	202	p 141	, 14	, 208	, 76
1600	DATA	192	, 193	, 173	, 16	, 208	, 9,	128,	141
1610	DATA	16,	208,	173,	32,	202,	141	p 14,	208
1620	DATA	238	r 16,	202,	238	, 16,	202	p 24,	173
1630	DATA	16,	202,	105,	43,	141,	19,	202,	173
1640	DATA	19,	202,	105,	43,	141,	22,	202,	173
1650	DATA	22,	202,	105,	43,	141,	25,	202,	173
1660	DATA	25,	202,	105,	43,	141,	28,	202,	173
1670	DATA	28,	202,	105,	43,	141,	31,	202,	173
1680	DATA	30,	208,	240,	3,	L41,	160,	194,	76
1690	DATA	49,	234,	120,	169	, 0,	141,	20,	3
1700	DATA	169	, 192	r 141	, 21	, 3,	88, <	56, 0
1710	DATA	255	, 255	, 0,	0, 255, 255, (			3, 0



	Diamond Drop

	Matt Giwer 64 Version by Eric Brandon

	Catch the falling diamonds—if you can. This fast-action game is easy to play. "Diamond Drop" is a game that requires good judgment and quick reflexes. It's fast and easy to play. To insure fast action, it is written predominantly in machine language. BASIC is used only to print instructions, set up the display, select the skill level, and initiate the drop. The game display starts with six rows of objects at the top of the screen and a stack of six catching trays at the bottom. As the objects begin to drop, you must use the L and; keys to maneuver the trays and catch the objects. To make play more challenging, one tray disappears whenever the last ball drops from a row. Thus, you have only one tray with which to catch objects from the last row. When all the objects have dropped, you start again with six rows of objects and six trays. Play continues until a total of five objects hit the ground. Since the DATA statements comprise the machine language program for the game, it is essential that they be typed correctly Be sure to SAVE a copy of the program before you attempt to RUN it, since an error in typing may cause your computer to lock up, forcing you to turn the power off to recover. If Diamond Drop fails to RUN properly, the problem will most likely be a mistyped number somewhere in the DATA statements, so check carefully. Diamond Drop 5 POKE 53280,12:POKE53281,0 7 IF PEEK(49152)<>120THENGOSUB49000 9 SYS 49745 10 PRINT"{CLRHwHT}"TAB(13)"DIAMOND DROP" 20 PRINT"{5 D0WN}{YEL}{5 SPACES}CATCH THE DIAMONDS BEFORE THEY 30 PRINT"{DOWN}{5 SPACES}TOUCH THE GROUND. YOU HAV E FIVE 40 PRINT"{DOWN}{5 SPACES}CHANCES.

	90



	Dexterity

	45 PRINT"{2 DOWN}{WHT}{13 SPACES}L - MOVE LEFT 46 PRINT"{13 SPACES}; - MOVE RIGHT{YEL}" 50 PRINT"{5 DOWN}g63{9 SPACES}{RVS}HIT ANY KEY T 0 BEGIN" 60 GETA$:IFA§=""THEN60 65 GOSUB 1000 70 PRINT" {CLRHWHT} SCORE 00000{4 SPACES } CHANCES : Q QQQ " 71 SPEED = 53241 72 PADDLES=124096+4095 73 FLAG=124096+4094 : POKE FLAG,0 74 WIDTH = 124096+15256+1516+11 75 POKE PADDLES,6 : POKE WIDTH,W : POKE SPEED,10-S 78 ROW(6)=81:ROW(5)=81:ROW(4)=207:ROW(3)=207:ROW(2 )=90:ROW(1)=90 80 PRINT" {YELHRVS}"; : F0RI = 1T038 : PRINT"Z" ; :NEXT:P RINT"{OFF} "; 85 PRINT" {YEL}{RVS}"; : F0RI=1T038 .-PRINT"Z" ; :NEXT:P RINT"{OFF} "; 90 PRINT" {CYN}{RVS}";:FORI=lT038:PRINT"P";:NEXT:P RINT"{OFF} "; 95 PRINT" {CYN}{RVS}";:F0RI=1T038:PRINT"P";:NEXT:P RINT"{OFF} "; 100 PRINT" {OFF}&73";:F0RI=1T038:PRINT"W";:NEXT: PRINT" "; 102 PRINT" {OFF}g7>T;:F0RI=1T038:PRINT"W";:NEXT: PRINT" "; 105 PRINT"{WHT}"; 109 REM 40 SPACES IN NEXT LINE 110 FORI=1TO17:PRINT"{40 SPACES}";:NEXT 120 PRINT"{HOME}"; 130 FOR 1=1984 TO 2023 : POKE I,248:POKE 1+54272,1 0:NEXT 140 IF PEEK(789)<>1216THENSYS 124096 150 FOR ROW = 6 TO 1STEP-1.-FOR CHAR=1 TO 38 155 FOR K=l TO 600-CHAR10+(6-ROW)20-50(9-PEEK(S PEED)):NEXT 157 IF PEEK(FLAG) THEN 2000 160 P=RND(1)38+1 170 IF PEEK(1024+ROW40+P)=32THEN160 180 POKE 1024+ROW*40+P,ROW(ROW) 190 NEXTCHAR 191 SYS 49745 192 FORQ=1TO2:POKE54296,05 :POKE5427 7,5:POKE54278, 218 193 POKE 54273,150 :POKE54272,139:POKE54276,17 194 FORT=1TO50:NEXT:POKE54276,16:FORT=1TO10:NEXT 195 NEXTQ 197 IF ROW >1 THENSYS 49691

	91



	200 NEXTROW 201 FOR K=l TO 300:NEXTK 205 POKE PADDLE,6 206 IF PEEK(SPEED)=2 AND PEEK(WIDTH)>1 THEN POKE W IDTH,PEEK(WIDTH)-l 207 IF PEEK(SPEED)>2 THEN POKE SPEED,PEEK(SPEED)-1 210 PRINT"{HOME}{DOWN}"; 220 GOTO 80 999 END 1000 PRINT"{CLR}{7 SPACES}DIFFICULTY{4 SPACES} {5 DOWN}" 1010 INPUT"{WHT}SPEED (1-9){YEL}{3 RIGHT}5{3 LEFT} ";S 1015 IF S>9 OR S<1 THEN 1010 1020 INPUT"{3 DOWN}{WHT}WIDTH OF PADDLES (1-9) {YEL}{3 RIGHT}4{3 LEFT}";W 1030 IF W>9 OR W<1 THEN 1020 1040 RETURN 2000 PRINT"{HOME}{10 DOWN}{2 SPACES}{YEL}GAME OVER - HIT SPACE TO CONTINUE" 2010 POKE 198,0 2020 GETA$:IFA$<>" "THEN2020 2030 RUN 65 49000 PRINT" {WHT}{CLR}{2 DOWNLOADING MACHINE LANG UAGE...{3 DOWN}":TI$="000000" 49005 1=49152 49007 PRINT"READY IN"STR$(31-VAL(TI$))" SECONDS {UP}" 49010 READ A:CK=CK+A:IF A=256 THEN 49030 49020 POKE I,A:I=I+l:GOTO 49007 49030 IFCK<>89323 THEN PRINT "ERROR IN LINES 49152 TO 49840" .-STOP 49040 RETURN 49152 DATA 120,169,192,141,21,3,169 49160 DATA 29,141,20,3,88,169,18 49168 DATA 141,253,207,169,0,141,250 49176 DATA 207,141,247,207,141,248,207 49184 DATA 96,173,255,207,141,252,207 49192 DATA 172,253,207,169,32,153,151 49200 DATA 7,200,169,160,174,251,207 49208 DATA 153,151,7,200,202,208,249 49216 DATA 169,32,153,151,7,206,252 49224 DATA 207,208,3,76,3,193,172 49232 DATA 253,207,169,32,153,71,7 49240 DATA 200,169,160,174,251,207,153 49248 DATA 71,7,200,202,208,249,169 49256 DATA 32,153,71,7,200,206,252 49264 DATA 207,208,3,76,3,193,172 49272 DATA 253,207,169,32,153,247,6

	92



	49280 DATA 200,169,160,174,251,207,153 49288 DATA 247,6,200,202,208,249,169 49296 DATA 32,153,247,6,200,206,252 49304 DATA 207,240,123,172,253,207,169 49312 DATA 32,153,167,6,200,169,160 49320 DATA 174,251,207,153,167,6,200 49328 DATA 202,208,249,169,32,153,167 49336 DATA 6,200,206,252,207,240,91 49344 DATA 172,253,207,169,32,153,87 49352 DATA 6,200,169,160,174,251,207 49360 DATA 153,87,6,200,202,208,249 49368 DATA 169,32,153,87,6,200,206 49376 DATA 252,207,240,59,172,253,207 49384 DATA 169,32,153,7,6,200,169 49392 DATA 160,174,251,207,153,7,6 49400 DATA 200,202,208,249,169,32,153 49408 DATA 7,6,200,206,252,207,240 49416 DATA 27,172,253,207,169,32,153 49424 DATA 183,5,200,169,160,174,251 49432 DATA 207,153,183,5,200,202,208 49440 DATA 249,169,32,153,183,5,200 49448 DATA 165,197,201,42,208,13,173 49456 DATA 253,207,201,1,240,24,206 49464 DATA 253,207,76,40,193,201,50 49472 DATA 208,14,173,253,207,24,109 49480 DATA 251,207,201,39,240,3,238 49488 DATA 253,207,238,250,207,173,250 49496 DATA 207,205,249,207,240,3,76 49504 DATA 49,234,169,0,141,250,207 49512 DATA 169,112,133,251,169,7,133 49520 DATA 252,160,0,185,152,7,41 49528 DATA 127,201,32,208,74,200,192 49536 DATA 39,208,242,160,0,177,251 49544 DATA 201,81,240,37,201,207,240 49552 DATA 33,201,90,240,29,200,192 49560 DATA 40,208,237,56,165,251,233 49568 DATA 40,133,251,176,2,198,252 49576 DATA 166,251,208,220,166,252,224 49584 DATA 4,208,214,76,49,234,170 49592 DATA 152,24,105,40,168,138,145 49600 DATA 251,152,56,233,40,168,169 49608 DATA 32,145,251,32,251,193,76 49616 DATA 99,193,169,32,153,152,7 49624 DATA 32,81,194,169,15,141,24 49632 DATA 212,169,17,141,5,212,169 49640 DATA 213,141,6,212,169,2,141 49648 DATA 3,212,169,100,141,2,212 49656 DATA 169,5,141,1,212,169,135 49664 DATA 141,0,212,169,65,141,4



	49672 DATA 212,160,0,162,0,142,32 49680 DATA 208,232,208,250,200,208,247 49688 DATA 169,12,141,32,208,169,64 49696 DATA 141,4,212,160,39,185,0 49704 DATA 4,201,81,240,11,136,208 49712 DATA 246,169,1,141,254,207,76 49720 DATA 49,234,169,32,153,0,4 49728 DATA 76,49,234,152,72,160,10 49736 DATA 185,0,4,201,57,208,9 49744 DATA 169,48,153,0,4,136,76 49752 DATA 255,193,185,0,4,24,105 49760 DATA 1,153,0,4,104,168,96 49768 DATA 174,255,207,202,142,255,207 49776 DATA 232,169,152,133,251,169,7 49784 DATA 133,252,56,165,251,233,80 49792 DATA 133,251,176,2,198,252,202 49800 DATA 208,242,160,0,177,251,201 49808 DATA 160,240,4,200,76,59,194 49816 DATA 174,251,207,169,32,145,251 49824 DATA 200,202,208,250,96,160,0 49832 DATA 152,153,0,212,200,192,9 49840 DATA 208,248,96,256

	94



	4 Laser Bounce Frank L. Broadnax

	Don't let the ball get by you. The longer you can chip away at the bricks, the higher your score. "Laser Bounce" is a game of movement and trajectory similar to some of the earlier videogames. Using only the character set provided with the Commodore 64, it displays a spaceship, the laser balls which rebound from the ship, and the walls of energy you are trying to break through. Played with a joystick plugged into Control Port 2, the game begins with a simple title screen and a short musical introduction. At that point you're asked if you want to read the instructions before the game. If this is your first game, you would press Y, and the instructions appear. Once you've played the game, however, you can press N and go directly to the screen setup. The screen sets up quickly, with the present and high scores displayed at the top, your spaceship in the middle, and the six colored energy walls below. The number of spaceships remaining is indicated by the small circles near the top-right-hand corner of the display. As soon as the screen is completed, the game begins. Your spaceship fires its laser, and the ball appears. The ball will travel in one of four directions to start the game. It will move up and to the right, up and to the left, down and to the right, or down and to the left. Be especially watchful for the ball to move up, toward your spaceship, for you won't have much time to intercept it. Intercepting the laser ball makes it rebound and move toward the energy walls or the side of the screen. It will bounce off both, but you'll receive points only if it hits the wall and eliminates a brick. Ten points are awarded for each gap created. Although it doesn't matter which part of the ship the ball touches, it's best to use its center. Sometimes you may think you're in the right position, but the ball misses one wing of the ship and gets by you. Unlike other games of trajectory, the ball will not bounce at a different angle depending on where it strikes

	95



	the ship. No matter where the ball touches the spaceship, it will simply rebound. The ship moves rather slowly, so it's a good idea to keep track of the ball, especially when it gets trapped in the wall and is busy eliminating bricks. You should be able to tell when the ball will escape from the wall and head back toward you. Anticipating it is important: if your spaceship is out of position, it will be hard to recover in time to intercept. Because the spaceship moves three columns at a time, its movement is sometimes jerky, and can make it seem like the spaceship is changing position faster than it actually is. The laser ball is also hard to keep track of at times. Because it is drawn and erased each time it moves, it blinks off and on. However, when it erases bricks from the energy wall, it seems to disappear for a moment. If it is eliminating bricks rapidly, the best way to keep track of it is to watch the pattern of erasing bricks. Plotting where it will return toward your ship, you can move to that position. If you miss intercepting the ball, and it gets by you, your spaceship will reappear in the middle of the screen, fire its laser, and another round begins. You have a total of five spaceships during a game, the number remaining indicated by the display. If you erase all five energy walls, the game isn't over. Another five walls are drawn when you reach 4800 points, the total you should have after eliminating all the bricks. Each time all five walls are erased, another five appear to take their place. You receive no additional spaceships, however. As the game ends, a message appears asking if you want to play another game. Pressing Y sets up another screen after you've indicated whether you need to read the instructions again. The score will return to 0, but the previous high score remains as long as the computer is left on. The high score only prints once a ball is missed. You can quit playing simply by entering N when the prompt appears at the end of a game. Laser Bounce Variations It's easy to create several variations of this game simply by altering a few of the program lines. An interesting variation can be created by changing line 400. Instead of the value DY = - DY, insert DX = - DX. This will make the laser ball wind its way down through the energy walls, reappearing and moving toward the spaceship only after it's erased its way free.

	96



Dexterity		4

Another change can be made in lines 460 and 470. Insert GOTO 310 instead of GOTO 320. After a ball is missed, the energy screens will be redrawn, in effect making you start over. Your score will not return to 0, however. Changing the value of DX in line 335 will also create another variation of Laser Bounce. DX = 2 will alter the angle at which the ball rebounds. This can make the ball difficult to intercept, especially as the game begins and the ball moves up and to one side. You'll have to be fast to intercept it before it gets by you. Programmer's Notes It may be useful to outline some of the major subroutines of this game program so you can see how it all fits together.

Lines 5-170	Function Set up the title screen and send the program to the subroutine which plays the opening music. Begin the setup of the game instructions, and send the program to the subroutine at 35000, which contains the rest of the game description. Set variables and the screen. Ball movement loop begins. This is the main loop of the program. Ball starts from the end of the laser. Alter the direction of the ball each time it appears. Check to see if the ball touches a brick in the energy wall. Check to see if the ball is in contact with the spaceship. Subroutine to create the firing laser using only standard graphic characters. POKE in the graphic character and colors to create the energy walls. The reversed space with screen code value of 160 was used to make the walls. Create the spaceship using the graphic characters with screen code values of 73, 81, and 83, and two characters with the value of 67. Subroutine to move the spaceship. The ship moves three columns at a time by erasing its previous position and POKEing in the new location. The value is read from the joystick (PEEK 56320). This subroutine also keeps the spaceship on the screen. Scoring subroutine which starts in line 400, then moves to this section of the program. The score is printed to the screen, changing by 10 each time a brick is erased. Lines 25011 to 25019 redraw the bricks once the screen is cleared, depending on the score displayed.
180-220
230-335 330 335 336-337 400 420-450 10100 12000-12130
15000-15160
20000-20080
25000-25020

97



	27000-27040 Sound subroutine for the effect as the ball hits and erases the bricks. Values are POKEd into sound memory locations for attack (A), waveform (W), high sound register (HF), and low sound register (LO). The sound variables are set in line 260, at the opening of the program. 30000-30070 Subroutine to handle a missed ball and the high score. The spare spaceships are controlled here as well. Line 30030 increases PL by 1 each time a ball is missed. If PL exceeds 1098, then the game ends; otherwise, line 30070 POKEs a value of 102 in location PL, erasing one spare spaceship. 35000-35100 Remainder of the screen and game instructions. 40000-40240 Set values and the DATA statements for the music which plays at the opening of the game 45000-45030 Subroutine which asks the player whether another game is wanted. Laser Bounce 5 PRINT"{CLR}" 10 PRINT 20 PRINT 30 PRINT 40 PRINT 50 PRINTSPC(8)"**********************" 60 PRINTSPC(8)"{21 SPACES}" 70 PRINTSPC(8)"{4 SPACES}LASER{2 SPACES}BOUNCE {4 SPACES}" 80 PRINTSPC(8)"{21 SPACES}" 160 PRINTSPC(8) ^,,**********************^M170 GOSUB40010 180 PRINTTABU28) "DO YOU WISH INSTRUCTIONS" 190 PRINTTAB(96)"Y OR N" 200 GETA$:IFA$=""THEN200 210 IFA$="Y^UTHENPRINT^M{CLR}":GOSUB35010 220 IFA$<>"Y"THEN230 230 PRINT"{CLR}":POKE53280_/11:POKE53281,0 240 P1=1094:SC=0:CO=54272 250 FORR=54272T054296:POKER,0:NEXT 260 L=54296:W=54276:A=54277:HF=54273:LF=54272 270 POKEL,15 302 FORU1=1024TO1063 rPOKEUl,160:POKEU1+CO,11:NEXT 304 FORU2=1064TO1103:POKEU2,102:POKEU2+CO,11:NEXT 306 FORU3=1095TO1098:POKEU3,87:POKEU3+CO,1:NEXT 307 PRINTTAB(6)"{UP}{WHT}SCORE=" 308 PRINTSPC(23)"{3 UP}{WHT}HI=" 310 GOSUB12010



	Dexterity	4

	320 GOSUB15010 325 C=1161:V=1162:B=1163:N=1164:M=1165 330 REM BALL 335 X=19:Y=9:DX=1:DY=1 336 IFRND(1)<.5THENDY=-DY 337 IFRND(1)<.5THENDX=-DX 340 POKE1024+X+40Y,81:POKE55296+X+40Y,1 370 POKE1024+X+40Y,32 380 X=X+DX:IFX=0ORX=39THENDX=-DX 390 Y=Y+DY:IFY=24THENDY=-DY 395 BL=1024+X+40Y:C1=160 400 IFPEEK(BL)=C1THENDY=-DY:SC=SC+10:G0SUB25010:GO SUB27010 420 IFPEEK(BL)=67THENDY=-DY:GOTO390 430 IFPEEK(BL)=81THENDY=-DY:GOTO390 440 IFPEEK(BL)=85THENDY=-DY:GOTO390 450 1FPEEK(BL)=7 3THENDY=-DY:GOTO390 460 IFPEEK(BL)=102THENGOSUB30010:GOTO320 470 IFPEEK(BL)=87THENGOSUB30010:GOTO320 480 GOSUB20020:GOTO340 10000 REM LASER DELAY 10100 FORT=1TO100:NEXT:RETURN 12000 REM DRAW BRICKS 12010 FORQ1=1504TO1583:POKEQ1,160:POKEQ1+CO,7:NEXT 12030 FORQ2=1584TO1663:POKEQ2,160:POKEQ2+CO,6:NEXT 12050 FORQ3=1664TO1743:POKEQ3,160:POKEQ3+CO,8:NEXT 12070 FORQ4=1744TO182 3:POKEQ4,160:POKEQ4+CO,5:NEXT 12090 FORQ5=1824TO1903:POKEQ5,160:POKEQ5+CO,2:NEXT 12110 FORQ6=1904TO1983:POKEQ6,160:POKEQ6+CO,4:NEXT 12130 RETURN 15000 REM LASER SHIP & LASER FIRE 15010 FORZ=1144T01183:POKEZ,32:NEXT 15020 POKE1161,85:POKEl162,67:POKE1163,81:POKE1164 ,67:POKE1165,73 15030 FORZl=55416T055455:POKEZ1,1:NEXT 15040 POKE1203,66:POKE55475,2:GOSUB10100 15050 POKE1243,66:POKE55515,2:GOSUB10100 15060 POKEl283,66:POKE55555,2:GOSUB10100 15070 POKE1323,66:POKE55595,2:GOSUB10100 15080 POKE1363,66:POKE55635,2:GOSUB10100 15090 POKE1403_/81:POKE55675_/1:GOSUB10100 15100 POKE1203_/32:GOSUB10100 15110 POKE1243,32:GOSUB10100 15120 POKE1283_/32:GOSUB10100 15130 POKE1323_/32:GOSUB10100 15140 POKE1363_/32:GOSUB10100 15150 POKE1403_#32:GOSUB10100 15160 RETURN 20000 REM SHIP MOVEMENT

	99



	20020 IFPEEK(56320)oll9THEN 20030 20025 POKEC,32:POKEV,32:POKEB,32:M=M+3:N=N+3:B=B+3 :V=V+3:C=C+3 20030 IFPEEK(1183)=73THENM=1183:N=1182:B=1181:V=11 80:C=1179 20040 POKEM,73:POKEN,67:POKEB,81:POKEV,67:POKEC,85 20050 IFPEEK(56320)<>123THEN 20060 20055 POKEM,32:POKEN,32:POKEB,32:C=C-3:V=V-3:B=B-3 :N=N-3:M=M-3 20060 IFPEEK(1144)=67THENC=1143:V=1144:B=1145:N=11 46:M=1147 20070 POKEC,85:POKEV,67:POKEB,81:POKEN,67:POKEM,73 20080 RETURN 25000 REM PRINT SCORE 25010 PRINTTAB(12)"{UP}{WHT}"SC 25011 IFSC=4800THENGOSUB12010 25012 IFSC=9590THENGOSUB12010 25013 IFSC=14380THENGOSUB12010 25014 IFSC=19170THENGOSUB12010 25015 IFSC=23960THENGOSUB12010 25016 IFSC=28750THENGOSUB12010 25017 IFSC=33540THENGOSUB12010 25018 IFSC=38330THENGOSUB12010 25019 IFSC=43120THENGOSUB12010 25020 RETURN 27000 REM SOUND 27010 POKEA,9:POKEW,17:POKEHF,67:POKELF,15 27030 POKEW,0 27040 RETURN 30000 REM MISSED BALL & HI SCORE 30010 IFSOHITHENHI=SC 30020 PRINTSPC(26)"{3 UP}{WHT}^MHI 30030 P1=P1+1:IFP1>1098THENPRINTTAB(254)"{WHTjGAME {3 SPACES}OVER":GOTO45000 30070 POKEP1,102:POKEPl+CO,11:RETURN 35000 REM INSTRUCTIONS 35010 PRINTTAB(88)"WELCOME TO LASER BOUNCE" 35020 PRINTTAB(40)"THE OBJECT OF LASER BOUNCE IS T O REFLECT" 35030 PRINT"THE BALL BACK TO THE BRICKS WITH YOUR" 35040 PRINTTAB(40)"SPACE SHIP." 35050 PRINTTAB(40)"TO MOVE YOUR SHIP USE A JOY STI CK" 35060 PRINTTAB(40)"PLUGGED INTO CONTROL PORT #2." 35070 PRINTTAB(126)"PRESS SPACE BAR TO PROCEED" 35080 GETP$:IFP$=""THEN35080 35090 IFP$<>CHR$(32)THEN35080 35100 IFP$=CHR$(32)THENRETURN 40000 REM SONG AT BEGINING

	100



	Dexterity £^

	40010 SO=54272 40020 FORL=SOTOSO+24:POKEL,0 40030 POKESO+5,9:POKESO+6,40 40040 POKESO+24,15 40050 READHF,LF,DR 40060 IFHF<0THENRETURN 40070 P0KES0+1,HF:P0KES0,LF 40080 POKESO+4,33 40090 F0RT=1T0DR:NEXT 40100 POKESO+4,32:FORT=1TO50:NEXT 40110 GOTO40050 40120 DATA14,24,250,11,48,125,12,143,125,14,24,125 40130 DATA11,48,125,12,143,125,14,24,125,15,210,25 0 40140 DATA12,143,125,14,24,125,15,210,125,12,143,1 25 40150 DATA14,24,125,15,210,125,16,195,250,18,209,2 50 40160 DATA14,24,125,15,210,125,11,48,125,12,143,12 5 40170 DATA14,24,250,12,143,125,11,48,125,16,195,25 0 40180 DATA16,195,250,14,24,250,11,48,125,12,143,12 5 40190 DATA14,24,125,11,48,125,12,143,125,14,24,125 40200 DATA15,210,250,12,143,125,14,24,125,15,210,1 25 40210 DATA12,143,125,14,24,125,15,210,125,16,195,2 50 40220 DATA18,209,250,14,24,125,15,210,125,11,48,12 5 40230 DATA12,143,125,14,24,125,16,195,125,14,24,12 5 40240 DATA12,143,125,11,48,500,-1,-1,-1 45000 PRINTTAB(44)^M{WHT}D0 YOU WISH ANOTHER GAME Y OR *N" 45010 GETA$:IFA$=^HMTHEN45010 45020 IFA$^MY^MTHENPRINT^M{CLR}**^m:GOTO180 45030 IFA$=^MN^MTHENPRINT^H{CLR}":END

	101







	I



			Chapter

		Arcade-Style Games



	5 The Hawkmen of Dindrin Esteban V. Aguilar, Jr. 64 Version by Charles Brannon_________________

	Fly down through the dangerous skies of the planet Dindrin to collect stones. Retrieve enough of them and win the game, hut beware of the floaters and lizards. Several special techniques are used in this game, including animation, multicolor sprites, and sound effects, each of which is explained in the article. There's a strange planet named Dindrin where multicolor floaters and a giant sky skimmer drift through the daytime skies. On the surface of the planet, vicious land hunters come up from the ground and set polished golden stones in the sun. It's a form of worship too obscure, too alien to describe. Suddenly a strange-looking hawk-like creature dives down and snatches a stone. You are the hawkman. Your objective is to pick up the golden stones. Several special programming tricks went into this game. When you have the game running, watch the screen carefully. A patrol snake sweeps across the bottom of the screen. Airborne floaters pop up all over the screen. The hawkman's wings flap. The luminous stones at the bottom of the screen are protected by menacing lizards whose tongues wiggle venomously at you. To play the game, use a joystick plugged into the first port. Maneuvering is accomplished by pulling left on the joystick to go backward. Whenever you want to dive or fly upward, you must pull down or up (respectively) on the stick. One thing to keep in mind when ascending or descending is that you will move diagonally rather than straight up or down. The joystick response will be strange and difficult to master, but predictable. Once in a while, an obstacle such as a floater will get in your way; press the fire button to safely bump into the obstacle (and get points for it). There are a couple of things to consider before playing the

	105



	■^ Arcade-Style Games_______________________________ game. As time passes, you will lose energy. If your energy runs out, you will lose a life. Second, when you're flying, don't run into anything or you'll lose one of your lives. When all your lives are lost, the game is over. How It's Done Multicolored characters are used for the stones and the lizards. The patrol snake is a multicolored sprite. The animation (wing flapping, tongue wiggling) is done by switching between two custom character sets. Every object to be animated has two alternate views. The same image is copied into both character sets for shapes that should not move, such as the stones or the score line. A machine language routine is used for smooth, even horizontal motion for the patrol snake. Instead of being called when needed by BASIC, the machine language routine runs continuously in the background. The machine language routine also flips the character set. Interrupting the Commodore 64 We used the hardware interrupt request (IRQ). To place a machine language routine so that it automatically executes every 1/60 second, you change the IRQ vector at $0314 (it normally points to the ROM interrupt routines) to point to your machine language routine. After your routine executes, it exits with a JMP to the normal ROM routine. The setup is a little tricky. While you're storing the new IRQ value, you have to use SEI (SEt Interrupt disable bit) to prevent any interrupts from happening. If you don't, an interrupt could occur after you had stored the first byte of the vector value but before you changed the second. The interrupt would then vector through a "half-baked" value, and end up in limbo. After you've changed the IRQ vector, you clear the interrupt disable bit (CLI) and return with RTS to BASIC. The machine language routine will then be running continuously in the background, flipping the character set and moving the sprite. Multicolor Multicolor graphics are important for good arcade effects. A few years ago, graphic objects (such as a tank or plane) were always a single color. But increasing realism has been a feature of arcade graphics, and multicolored objects are an important aspect of this realism.

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	Arcade-Style Games	5

	Normally, when you define a custom character set, you create eight rows of pixels (picture elements, dots). Each row is eight dots (orbits) wide. With multicolor, each row is divided up into four two-bit pairs. Each pair of bits can hold a number from 0-3: 00, 01,10,11. You use a different number for each color. This reduces the resolution to four multicolor pixels per row, so the lizards and stones are composed of two characters each. You also have to tell the VIC-II chip that you are using multicolor. Do this with: POKE 53270, PEEK (53270) OR 16 Disable multicolor with: POKE 53270, PEEK (53270) AND 239 Here is a sample multicolor shape: rrrr r = red (arbitrary colors) rbbb b = blue ^rbgg g = green rbgg Let's say the binary codes for red, green, and blue are (respectively) 01,10, and 11. Substituting gives: 01 01 01 01 01010101 01 10 10 10 01101010 01 10 11 11 01101111 01 10 11 11 01101111 You can change the colors according to this key: 00 Background #0 color register - 53281 01 Background #1 color register - 53282 10 Background #2 color register - 53283 11 Color in lower 3 bits in color memory. That last line needs explaining. You know that to get variously colored characters, you POKE a number from 0-15 into the corresponding color memory location. However, colors 8-15 (accessed by the Commodore key) are really multicolors. Multicolor characters always are displayed with a color from 8-15. You won't get the eight alternate colors (such as gray), but the normal color on the key (15 = yellow). Just add eight to the normal color number. So, a bit value of 11 will take on the value in color memory. The other colors will come from the color registers (00 is transparent). 107



	■% Arcade-Style Games___________________________________ Multicolored sprites are similar. Instead of the normal 24-bit resolution, the bits are grouped into 12-bit pairs. The colors come from: 00 - Transparent, screen color 01 - Sprite multicolor register #0 53285 10 - Normal sprite color register 11 - Sprite multicolor register #1 53286 You tell the VIC-II chip that you are using a multicolored sprite by: POKE 53276, PEEK (53276) OR (2 T X) X is the sprite number, from 0 to 7. You can mix multicolored and regular sprites on the same screen. But all multicolored sprites will share the same two multicolor registers. Simple SID Chip Sound The "thrumming" noise is made by playing a low-pitched tone through the SID using the variable pulse wave and a fairly long (one-second) decay. Another sound effect (I can't really describe it) is made with white noise and a medium decay. The high byte of the pitch is changed as the note is played. There is also another sound effect created by the sawtooth waveform affecting the low byte of the pitch. Hawkmen of Dindrin 100 REM HAWKMEN OF DINDRIN 110 REM COMMODORE 64 VERSION 120 P0KE52,48:POKE56,48:CLR:GOSUB500:EN=500:GOT016 0 130 PRINT"{HOME}{RVS}{RED}";TAB(9)"{LEFT}"7EN;" {BLU}"7TAB(26-LEN(STR$(SC)))7SC7 140 IF EN<=0THEN410 150 RETURN 160 IF(PEEK(56321)AND15)<>15THENJS=PEEK(56321)AND1 *5 170 IFRND(1)>.9THENQ=LLRND(1)+(15RND(1)+2)LL:P0 KET+Q,FOOL:POKEC+Q,6 RND(1)+2 180 IFRND(1)<.7THEN200 190 Q=920+INT(20RND(1))2:Z=33-2(RND(1)>.7):POKE T+Q,Z:POKET+Q+1,Z+l 200 IFPEEK(V+31)THEN410 210 Q=PX+LLPY:POKET+Q,PC:POKEC+Q,6:EN=EN-l-9(1-( PEEK(56321)AND16)/16) 215 PRINT"{H0MEHrVS}{RED}"TAB(9)7"{LEFT}"7-EN(EN* >0)7"{LEFT} "7:IFEN<=0THEN410

	108



	Arcade-Style Games	5

	220 NX=PX+1+2(JS=11):NY=PY+(NX<0)-(NX>39):NX=-NX (NX<40)-40(NX<0) 230 NY=NY-(JS=13)+(JS=14):IFNY<20RNY>23THENJS=27-J S:NY=PY 240 WHATSIT=PEEK(T+NX+LLNY) 250 IF NY>22 THEN 300 260 IFWHATSIT=32THENPOKET+PX+LLPY,32:PX=NX:PY=NY: GOTO160 270 IFPEEK(56321)AND16THEN410 280 POKET+PX+LLPY,32:POKES+24,15:POKES+5,9:POKES+ 6,0:POKES+1,10 281 FORI=0TO10:POKES,120:POKES+4,32:POKES+4,33:NE XT:POKES+24_f0 290 WHATSIT=32:SC=SC+10:EN=EN-50:GOSUB130:GOTO250 300 JS=27-JS:IFWHATSIT<33ORWHATSIT>34THEN330 305 Q=(NXAND254)+LLNY:POKET+Q,32:POKET+Q+1,32:EN= EN+50 310 GOTO320 320 POKET+PX+LLPY,32:PX=NX:SC=SC+50:GOSUB130:GOTO 160 330 IFWH=32THEN160 340 REM GRABEM AND EAT 'EM UP 1 350 POKET+PX+LLPY,32:Q=LLNY+(NXAND254):POKET+Q,3 7:POKET+Q+1, 38:POKET+Q-LL,42 360 POKET+Q-LL+1, 36:POKEC+Q-LL,13:POKEC+Q-LL+1,13 370 POKES+24,15:POKES+1,0:POKES,255:POKES+3,8:POKE S+2,0:POKES+5,12:POKES+6,0 375 POKES+4,64:POKES+4,65:F0RW=1T01500:NEXT:POKES+ 4,64:FORL=STOS+24:POKEL,0:NEXT 380 POKE T+Q,33:POKET+Q+1,34:POKET+Q-LL,32:POKET+Q -LL+1,32 390 GOTO 430 400 REM PLAYER MEETS HIS DEMISE 410 POKES+24,15:POKES+5,9:POKES+6,0:POKES,200 420 FORI=0TO90STEP6:Q=PX+LLPY:POKET+Q,44+1/30:POK EC+Q,8RND(1) 425 POKE53280,16RND(1):POKES+1,1:POKES+4,128:POKE S+4,129:NEXT 427 FORL=STOS+24:POKEL,0:NEXT 430 POKE53280, 0 : IFLK3THENPOKET+35+LI2 , 32 440 POKET+PX+LL*PY,32:Z=PEEK(V+31):LI=LI+1:IFLI<4T HENEN=500:GOSUB720:GOTO160 450 SYS52992:REM TURN OFF ML 460 PRINT"{HOME}{3 DOWN}{RVS}";TAB(15);"{BLK}G {RED}A{CYN}MtPUR}E{RIGHT}{GRN}o{BLU}V{YEL}E {red}r{blu}^m470 printtab(7)"{down}{rvs}press {red}fire{blu} to play again" 480 if(peek(56321)and16)then480

	109





	Arcade-Style Games

	490 RUN 500 REM INITIALIZATION 510 POKE53280_/0:POKE53281,1 515 T=1024:C=55296:S=542 72:LL=40 520 CHSET=12288:IFPEEK(CHSET+264)=2 THEN 570 530 PRINT"{CLR}":C$="{BLK}{RED}{CYN}{PUR}{CRN} {YEL}{BLU}":FORI=1T07:PRINT"{HOME}{DOWN}";MID$ (C$,1,1);:GOSUB2000:NEXT 550 PRINTTAB(10)ⁿ{3 DOWN}{2 RIGHT}{BLK}READY IN {RED}22{BLK} SECONDS"; 560 GOSUB750:GOSUB 840 570 PRINT"{CLR}";:FOOL=41 575 FORL=STOS+24:POKEL,0:NEXT 580 PC=43:POKE53282,10:POKE53283,2 590 POKE 53272,(PEEK(53272)AND240)OR12:REM ENABLE {SPACE}NEW CHARACTER SET 600 POKE 53270,PEEK(53270)OR16 :REM SET MULTICOLOR MODE 610 PRINT"{HOME}{RED}{RVS}{2 SPACES}ENERGY 500 {2 SPACES}{BLU}{2 SPACES}SCORE{4 SPACES}0 {GRN}{2 SPACESJLIVES {OFF}{PUR}+ + +" 630 FORI=0TO39STEP2:Q=24LL+I:POKET+Q,39:POKET+Q+1 ,40:POKEC+Q,7:POKEC+Q+1,7:NEXT 640 FORI=0TO39STEP2 : Q=23LL+I: POKET-I-Q, 33 : POKET+Q+1 ,34:POKEC+Q,13:POKEC+Q+1,13:NEXT 650 Q=10+23LL:POKET+Q,35:POKET+Q+1,36 660 V=53248:REM START OF VIC-II CHIP REGISTERS 670 POKEV,220:POKEV+1,194:POKEV+21,1:POKEV+39,7:PO KE2040,13 680 POKEV+23,1:POKEV+29,1:POKE53285,3:POKE53286,4: POKE53276,PEEK(53276)ORl 681 FORI=0TO63:POKE832+I,0:NEXT:RESTORE 685 FORI=0TO18:READA:POKE832+8+I,A:NEXT 690 DATA192,0,3,240,0,15,124,85,95,255,0,12,8,0,3, 0,0,0,240 700 F0RI=1T05 : Q=40RND( 1) + (10RND (1) +3 ) LL: POKET+Q ,FOOL:POKEC+Q,6RND(1)+2:NEXT 710 SYS52992:REM START ML ROUTINE 720 PX=5:PY=5:PC=43:POKET+PX+LLPY,PC:POKEC+PX+LL PY,6 730 IF(PEEK(56321)AND15)=15THEN730 740 RETURN 750 RESTORE:FORI=0TO18:READA:NEXT:FORI=0TO96:READA :POKE52992 + I, A: NEXT .-RETURN 760 DATA 120,173,21,3,201,234,208,19 770 DATA 169,39,141,20,3,169,207,141 780 DATA 21,3,169,0,133,251,133,252 790 DATA 76,37,207,169,49,141,20,3 802 DATA 169,234,141,21,3,88,96,165

	110



	Arcade-Style Games	5

	804 DATA 251,141,0,208,173,16,208,41 806 DATA 254,5,252,141,16,208,24,165 808 DATA 251,105,4,133,251,165,252,105 810 DATA 0,133,252,240,12,165,251,201 812 DATA 91,144,6,169,0,133,251,133 814 DATA 252,165,162,74,144,8,173,24 816 DATA 208,73,2,141,24,208,76,49 818 DATA 234 840 POKE56334,PEEK(56334)AND254:POKEl,PEEK(1)AND251 841 FORI=0TO511POKE13312+I,PEEK(54272+I):POKE1536 0+I,PEEK(54272+l):NEXT 842 POKEl,PEEK(1)OR4:POKE56334,PEEK(56334)ORl 860 READA:IFA=-1THENRETURN 870 FORJ=0TO7:READB:POKECHSET+A8+J,B:NEXTJ:GOTO860 880 DATA 32,0,0,0,0,0,0,0,0 890 DATA 33,2,9,9,9,9,9,2,0 900 DATA 34,160,88,88,88,88,88,160,0 910 DATA 35,12,3,16,196,195,63,3,3 920 DATA 36,0,192,252,236,252,240,192,192 930 DATA 37,3,35,131,139,139,171,35,3 940 DATA 38,192,192,224,232,202,194,194,200 950 DATA 39,64,80,84,85,85,85,85,85 960 DATA 40,1,5,21,85,85,85,85,85 970 DATA 41,0,102,219,36,126,137,66,60 980 DATA 42,0,15,0,51,63,15,15,3 990 DATA{2 SPACES}288,0,0,0,0,0,0,0,0 1000 DATA 289,2,9,9,9,9,9,2,0 1010 DATA 290,160,88,88,88,88,88,160,0 1020 DATA 291,12,3,0,192,195,63,3,3 1030 DATA 292,0,192,252,204,252,240,192,192 1040 DATA 293,3,3,35,171,139,139,131,35 1050 DATA 294,192,200,194,194,202,232,224,192 1060 DATA 295,64,80,84,85,85,85,85,85 1070 DATA 296,1,5,21,85,85,85,85,85 1080 DATA 297,129,102,90,36,126,82,36,24 1090 DATA 298,0,15,0,48,63,3,15,15 1100 DATA 43,153,219,231,255,90,24,36,66 1110 DATA 299,24,90,231,255,219,153,36,66 1120 DATA 44,217,219,231,75,2,24,36,66 1130 DATA 45,216,225,235,69,7,2,40,66 1140 DATA 46,192,192,145,3,67,1,72,130 1150 DATA 47,192,128,8,1,1,0,16,128 1160 DATA 300,217,219,247,99,22,24,36,68 1170 DATA 301,216,225,227,71,23,130,32,66 1180 DATA 302,192,200,129,3,131,1,64,130 1190 DATA 303,192,144,0,1,1,0,8,128 1200 DATA -1

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5	Arcade-Style Games

2000 PRINT" {RVS} {2 RIGHT} {2 RIGHT}{2 SPACES} {2 RIGHT} {3 RIGHT} {RIGHT} {2 RIGHT} {RIGHT} {3 RIGHT} {RIGHT}{3 SPACES}{RIGHT} {3 RIGHT} ii 2010 PRINT" {RVS} {2 RIGHT} {RIGHT} {2 RIGHT} {RIGHT} {3 RIGHT} {RIGHT} {RIGHT} {2 RIGHT} {2 SPACES}{RIGHT}{2 SPACES}{RIGHT} {3 RIGHT} {2 SPACES}{2 RIGHT} " 2020 PRINT" {RVS}{4 SPACES}{RIGHT}{4 SPACES} {RIGHT} {RIGHT} {RIGHT} {RIGHT}{2 SPACES} {3 RIGHT} {RIGHT} {RIGHT} {RIGHT}{2 SPACES} [2 RIGHT} {RIGHT} {RIGHT} " 2030 PRINT" {RVS} {2 RIGHT} {RIGHT} {2 RIGHT} {RIGHT} {RIGHT} {RIGHT} {RIGHT} {RIGHT} {2 RIGHT} {3 RIGHT} {RIGHT} {3 RIGHT} {2 RIGHT}{2 SPACES}" 2040 PRINT" {RVS} {2 RIGHT} {RIGHT} {2 RIGHT} {2 RIGHT} {RIGHT} {2 RIGHT} {2 RIGHT} {RIGHT} {3 RIGHT} {RIGHT}{3 SPACES}{RIGHT} {3 RIGHT} {3 DOWN}"

2060 PRINTSPC(15) {3 SPACES}" 2070 PRINTSPC(15);"{RVS} 2080 PRINTSPC(15);"{RVS} {3 SPACES}"			£{2 SPACES}E*§{2 RIGHT}
			{2 {2	RIGHT} RIGHT}	{2 RIGHT} {2 RIGHT}

2090 2100 2110		PRINTSPC(15);"{RVS}	{2 RIGHT} {2 RIGHT} "
2090 2100 2110		PRINTSPC(15);^MB*i{RVS}{2 SPACES}{OFF}£ {2 SPACES}{RVS} {2 DOWN}" PRINT"{3 SPACES}{RVS}{3 SPACES}{2 RIGHT} {3 SPACES}{RIGHT} {3 RIGHT} {RIGHT}{3 SPACES} {2 RIGHT}{3 SPACES}{2 RIGHT}{3 SPACES}{RIGHT} {3 RIGHT} " PRINT"{3 SPACES}{RVS} {2 RIGHT} {2 RIGHT} {2 RIGHT}{2 SPACES}{2 RIGHT} {RIGHT} {2 RIGHT} {RIGHT} {2 RIGHT} {2 RIGHT} {2 RIGHT}{2 SPACES}{2 RIGHT} " PRINT"{3 SPACES}{RVS} {2 RIGHT} {2 RIGHT} {2 RIGHT} {RIGHT} {RIGHT} {RIGHT} {2 RIGHT} {RIGHT}{3 SPACES}{3 RIGHT} {2 RIGHT} {RIGHT} {SPACE}{RIGHT} " PRINT"{3 SPACES}{RVS} {2 RIGHT} {2 RIGHT} {2 RIGHT} {2 RIGHT}{2 SPACES}{RIGHT} {2 RIGHT} {RIGHT} {2 RIGHT} {2 RIGHT} {2 RIGHT} {2 RIGHT}{2 SPACES}" PRINT"{3 SPACES}{RVS}{3 SPACES}{2 RIGHT} {3 SPACES}{RIGHT} {3 RIGHT} {RIGHT}{3 SPACES} {2 RIGHT} {2 RIGHT} {RIGHT}{3 SPACES}{RIGHT} {SPACE}{3 RIGHT} " RETURN
2120
2130
2140
2150
2160



	5 Minefield Sean Igo 64 Translation by Gregg Peele

	Your job is to get your trucks in quickly, defuse the bombs (especially the flashing ones which are about to go off), and get out as fast as you can. This game has four skill levels. In this game, you drive a truck around to gather and defuse time bombs before they explode—all the while avoiding mines and bomb craters. Playing the Game You find yourself in the center of a small minefield with several bombs, represented by circles, and a generous number of mines, shown as X's. Your truck is a diamond. To defuse the bombs, just run over them with the truck. When the bombs first appear, they are innocent-looking little circles. After a short time—the rate varies from bomb to bomb— they turn reverse-field. This means watch it. Soon they begin to blink, and you have only a few blinks to defuse them before they explode. Any mines (or heroic defusing teams) caught in the explosion will be instantly lost. Bombs caught in the explosion will explode, whether they were ready to or not. Your truck can move in only four directions. It can wrap around all four edges of the screen. Don't run it into the mines or the craters () left by the bombs or your truck will be destroyed. Once you begin moving, your truck cannot stop until it is blown up or until the current minefield is cleared of bombs. Skill Levels and Scoring* "Minefield" has four skill levels. Skill levels differ only in the number of trucks you get. Level 0, the easiest, has four trucks. Level 1 has three. Level 2 has two, and level 3 has one. Scoring: 10 points for a normal bomb 20 points for a reverse-field bomb 30 points for a blinking bomb -10 points at the end of an explosion for every bomb that went off. This is incentive to defuse more than one or two bombs in the later explosions.

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	5	Arcade-Style Games

	Minefield 30 REM MINEFIELD FOR C-64 45 POKE53280,0:POKE53281,0 50 GOSUB 1130 60 REM ---INITIALIZE VARIABLES--- 70 DIM BT(37),B3(37),B4(37),BP(37),BS(37),XM(4),YM (4),BC(25) 80 DEF FNY(X)=INT((X-1024)/40) 90 DEF FNX(X)=(X-40FNY(X))-1024 100 DEF FNS(X)=1024+PX+40PY 110 DEF FNP(X)=1307+INT(34RND(1))+40INT(15RND(1 )) 120 DEF FNN(X)=PEEK(FNS(X)) 130 FORJ=l TO 4:READ XM(J),YM(J):NEXT 140 DATA* *0,-1,0,1,-1,0,1,0* 150 SC=0:BT=1680:NB=4:NW=0:D=54272 160 PRINT"{CLR}";:POKE 53272,21 170 PRINT"{RVS}{WHT}MINE**_z SCORE: 0" 180 PRINT"{RVS}{WHt}****-{RIGHT}HI SCORE:";HS 190 PRINT"{RVS}(wHT}FIELD-{RIGHT}WAVE: 1" 200 PRINT"{RVS}{WHT}{8 SPACES}-{RIGHT}";:IF NL<>1 {SPACE}THEN FORJ=l TO NL-1:PRINT"Z";:NEXT 210 FORJ=1024 TO 1183:IFPEEK(J)=32 THEN POKE J,160 :POKEJ+D,l 220 NEXT 230 xp$="{red}u-l{down}{4 left}uu-ii{down}{6 left} uuu-iii{downT{7 left}*****{down} [7 left}jjj-kkk" 235 xp$=xp$+"iredj idown}{6 left}jj-kk{down} {4 LEFT}J-K" 240 S$="{HOMETT24 DOWN}" 250 Q$="{WHT}{40 RIGHT}" 260 XR$="{WHT}{3 SPACES}{DOWN}{4 LEFT}{5 SPACES} {DOWN}{6 LEFT}{7 SPACES}{DOWN}{7 LEFT} {3 SPACES}{3 SPACES}{DOWN}{7 LEFT}{7 SPACES}" 265 XR$=XR$+"{DOWN}{6 LEFT}{5 SPACES}{DOWN} {4 LEFT}{3 SPACES}" 270 REM ---SET UP NEXT WAVE--- 280 BG=0:NW=NW+1:IF NW>11 THEN 310 290 NB=NB+1.5:IF NW=1 THEN 330 300 IF NW<6 THEN BT=BT-180 310 PRINT"{HOME}{2 DOWN}{RVS}";TAB(15);NW 320 POKE FNS(l),32:FORJ=l TO NB:POKEBP(J),32:NEXT 325 FORJ=l TO 25:POKE BC(J),32:NEXT 3 30 BN=INT(NB):FORJ=l TO NB:BS(J)=1:NEXT 340 FORJ=l TO NB 350 BT(J)=(.4+INT(61RND(l))/l00)BT 360 B3(J)=BT(J)+.5BT(J):B4(J)=B3(J)+.25BT(J) 3 70 NEXT

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	Arcade-Style Games

	380 PX=19:PY=15:POKE FNS(1),90:POKEFNS(1)+D,1 390 FORJ=l TO NB 400 BP(J)=FNP(1):IF PEEK(BP(J))<>32 THEN 400 410 POKE BP(J),87:POKEBP(J)+D,8:NEXT:NN=0 415 FORJ=l TO 25 416 BC(J)=FNP(1):IF PEEK(BC(J))<>32 THEN 416 417 IF PEEK(BC(J)+1)=87 THEN 416 419 POKEBC(J),86:P0KEBC(J)+D,5:NEXT 420 GET R$:IF R$<>"" THEN 420 430 DR=0:TX=TI 440 REM ---GET COMMANDS--- 450 R=(15-(PEEK(56321)AND15))*2 460 IFR<>0THENDR=LOG(R)/LOG(2){41 SPACES} 470 IFR=0THEN490 480 REM ---MOVE TRUCK--- 490 IF DR=0 THEN 600 500 POKE FNS(l),32:PX=PX+XM(DR):PY=PY+YM(DR) 510 IF PX<0 THEN PX=39 520 IF PX>39 THEN PX=0 530 IF PY<4 THEN PY=24 540 IF PY>24 THEN PY=4 550 X=FNN(1) 560 IF X=32 THEN POKE FNS(1),90:POKEFNS(1)+D,1:GOT O 600 570 IF X=42 OR X=86 THEN 960 580 GOTO 890 590 REM ---UPDATE BOMBS--- 600 NN=NN+1:IF NN>INT(NB)THEN NN=1 610 IF BS(NN)=0 THEN 600 620 TG=TI-TX 630 IF TG>B4(NN) THEN Nl=NN:GOTO 720 640 IF BS(NN)>2 THEN 690 650 IF TG>BT(NN) THEN BS(NN)=2 660 IF TG>B3(NN) THEN BS(NN)=3 670 IF BS(NN)=1 THEN 450 680 IF BS(NN)=2 THEN POKE BP(NN),215:POKEBP(NN)+D, lzGOTO 450 690 IF BS(NN)=3 THEN POKE BP(NN),87:POKEBP(NN)+D,1 :BS(NN)=4:GOTO 450 700 IF BS(NN)=4 THEN POKE BP(NN),215:POKEBP(NN)+D, l:BS(NN)=3:GOTO 450 710 REM ---BOMB EXPLODES--- 720 TQ=TI:PD=0 725 X$="{OFF}"+LEFT$(S$,FNY(BP(Nl))-2)+LEFT$(Q$,FN X(BP(N1))-1) 730 BS(N1)=0:N2=0:PRINTX$;XP$; 740 FORJ=l TO NB:X=PEEK(BP(J)):IF BS(J)=0 THEN 760 750 IF X<>87 AND X<>215 AND X<>218 THEN N2=J 760 NEXT:IF FNN(1)<>90 AND FNN(1)<>218 THEN PD=1

	115



	5	Arcade-Style Games

	770 PRINTX$;XR$;:GR=129{4 SPACES}:GOSUB2000 780 F0RJ=1T0NB:IF PEEK(BP(J))=32 AND BS(J)<>0 THEN POKE BP(J),87-128(BS(J)>1) 790 NEXT:BN=BN-1 800 IF PD=1 THEN 960 810 IF BN=0 THEN 840 820 IF N2=0 THEN TX=TX+(TI-TQ):GOTO 450 830 Nl=N2:GOTO 725 840 PRINT"{HOME}{2 DOWN}{RVS}";TAB(20); 850 FORJ=l TO 20:PRINT"{RVS}COMPLETED{9 LEFT}";:FO RK=1 TO 100 .-NEXT 860 PRINT"{RVS}{9 SPACES}{9 LEFT}";:FORK=l TO 100: NEXT:NEXT 870 SC=SC-10(INT(NB)-BG):IF SC<0 THEN SC=0 880 PRINT"{4 LEFT}{3 UP}{10 SPACES}{10 LEFT}";SC:G OTO 280 885 REM ---BOMB GATHERED--- 890 BG=BG+l:TQ=TI:POKE FNS(1),218 895 FORJ=l TO NB:IF PEEK(BP(J))=218 THEN AJ=BS(J): BS(J)=0 900 NEXT 910 IF AJ=4 THEN AJ=3 920 SC=SC+10AJ:PRINT^M{HOME}{RVS}";TAB(16);SC 930 GR=33:GOSUB2000:BN=BN-1:IF BN=0 THEN 840 940 TX=TX+(TI-TQ):GOTO 450 950 REM ---PLAYER DESTROYED--- 960 GR=129:GOSUB2000 961 TQ=TI:FORJ=l TO 20:POKE FNS(1),42:FORK=l TO 25 :NEXT:POKE FNS(1),170 970 FORK=l TO 25:NEXT:NEXT:POKE FNS(1),32:NL=NL-1 {19 SPACES} 980 POKE 1153+NL,160:DR=0:PX=19:PY=15 990 IF NL=0 THEN 1045 1000 IF BN=0 THEN 840 1010 GET R$:IF R$<>"" THEN 1010 1020 FORJ=lTONB:IF PEEK(BP(J))=32 AND BS(J)<>0 THE N POKE BP(J),87-128(BS(J)>1) 1030 NEXT 1040 POKE FNS(1),90:TX=TX+(TI-TQ):GOTO 450 1045 IF SOHS THEN HS=SC: PRINT" {HOME} {DOWN} {RVS }" ; TAB(19);HS 1050 FORJ=l TO 1500:NEXT:PRINT"{HOME}{WHT}{2 DOWN} {RVS}";TAB(20);^,,GAME OVERlDOWN} {WHT} {9 LEFT}P LAY AGAIN?"; 1060 PRINT"(Y/N){4 LEFT}"; 1080 PRINT"{RVS}Y/{OFF}N{3 LEFT}"; 1081 FORJ=l TO 99:NEXT 1082 PRINT"{OFF}Y{RVS}/N{3 LEFT}"; 1083 FORJ=l TO 99:NEXT

	116



	Arcade-Style Games	5

	1084 GET R$:IF R$="Y" THEN 1110 1090 IF R$<>"N" THEN 1080 1100 PRINT"{CLR}{WHT}LATER ONI":END 1110 GOSUB 1130:GOTO 150 1120 REM ---INSTRUCTIONS--- 1130 PRINT" {CLR} {RVS} {WHT}m{ SHIFT-SPACE}l. {SHIFT-SPACE}N{SHIFT-SPACE}E{SHIFT-SPACE}F { SHIFT-SPACE }.l{ SHIFT-SPACE } E { SHIFT-SPACE } L {SHIFT-SPACE}D":POKE 53272,23 1140 PRINT"{WHT}DO YOU NEED INSTRUCTIONS (Y/N)" 1150 GET R$:IF R$="N" THEN 1410 1160 IF R$<>"Y" THEN 1150 1180 PRINT"{CLR}{WHT}{DOWN}THE OBJECT OF THIS GAME IS TO PICK UP" 1190 PRINT"{WHT}AS MANY BOMBS AS YOU CAN BEFORE TH EY" 1200 PRINT"{WHT}EXPLODE. TO PICK UP A BOMB, JUST R UN" 1210 PRINT"{WHT}OVER IT WITH YOUR TRUCK." 1220 PRINT"{WHT}BOMBS WILL EXPLODE AFTER A SHORT T I ME." 1230 PRINT" {WHT}l.F A BOMB TURNS REVERSE-FIELD, BE {SPACE}CARE-" 1240 PRINT" {WHT}FUL WITH IT. I.F IT STARTS TO BLINK , IT" 1250 PRINT"{WHT}WILL VERY SHORTLY EXPLODE-WATCH OU Til" 1260 PRINT"{WHT}BOMBS WILL CHAIN-REACT; ONE BOMB C AUGHT" 1270 PRINT"{WHT}IN ANOTHER'S EXPLOSION WILL ALSO B LOW" 1280 PRINT"{WHT}UP. IF YOU ARE CAUGHT IN A BOMB'S {SPACE}" 1290 PRINT"{WHT}EXPLOSION, YOU WILL BE BLOWN UP." 1300 PRINT"{WHT}ALSO, DO NOT RUN INTO BOMB CRATERS ()" 1310 PRINT"{WHTjOR MINES (X) OR YOU'LL BE TOTALLED ii 1320 PRINT"{WHT}THE CONTOLS ARE: 1 TO GO UP" 1330 PRINT"{WHT}Tl7 SPACES}CTRL TO GO LEFT" 1340 PRINT"{WHT}{17 SPACES}2 TO GO RIGHT" 1350 PRINT"{WHT}{17 SPACES} TO GO DOWN" 1355 PRINT"{WHT}OR YOU CAN USE A JOYSTICK IN PORT {SPACE}1." 1360 PRINT"{WHT}YOUR TRUCK CANNOT STOP ONCE YOU BE GIN" 1370 PRINT"{WHT}MOVING. IT CAN WRAP-AROUND BOTH TH E" 1380 PRINT"IWHT}THE TOP AND SIDES OF THE SCREEN."

	117



	^% Arcade-Style Games

	1390 PRINT"{DOWN}{WHT}P{WHT}RESS RETURN TO CONTINU E"; 1400 GET R$:IF R$<>CHR$(13) THEN 1400 1410 PRINT"{CLR}^{WHT}ELECT SKILL SETTING (0-3)" 1420 GET R$:IF R$<"0" OR R$>"3" THEN 1420 1430 NL=4-VAL(R$):RETURN 1900 END 2000 REM SOUND OF EXPLOSION 2010 QW=54272 2020 FORS=QWTOQW+24:POKES,0:NEXT 2025 POKEQW+24,47 2030 POKEQW+5,64+7 :POKEQW+6,240 2050 POKEQW+4,GR :POKEQW+l,36:POKEQW,85 2060 FORT=1TO250:NEXT 2070 FORT=15TO0STEP-1 :POKEQW+24_/INT(T):NEXT 2080 RETURN



	118



	5 Cylon Zap_______ Mark Dudley 64 Translation by Gregg Peele__________________________ Quick reflexes are what you'll need for this fast-action game. "Cylon Zap" is an arcade-style game. A space station in the center of the screen, which you must defend at all costs, is attacked continually by Cylon ships. You must shoot them before they dive (kamikaze style) into the space station. To defend against the Cylons, you have two weapons. First, the joystick is moved up, down, right, or left to fire lasers in any of these four directions. Second, the fire button detonates a smart bomb, which immediately clears the screen of all visible attackers. Smart bombs should be used sparingly, for only three are available at the beginning of play. The score and the number of remaining bombs are continually updated at the upper-left corner of the screen. When the score reaches 30, the flank attackers begin to increase speed. When your score reaches 50, the attackers from the top and bottom increase their speed. If your score exceeds 60, you win bonus smart bombs. If your point total is a high score since the program was first loaded, you enter your initials with the joystick. Moving the stick right or left lets you step through the alphabet forward or backward. When you find the correct letter, select it with the fire button. Be sure not to hold the fire button down too long when selecting your initials, or you may inadvertently choose the wrong letters. Cylon Zap 100 POKE52,48:POKE56,48:CLR 125 DATA28,149,100,25,30,100,33,135,100,37,162,50, 50,60,50 130 DATA42,62,100,37,162,50,50,60,50,42,62,100,33, 135,100 140 DATA28,49,100,25,30,100 145 F0RX=1T036:READRT:NEXT 150 PRINT"{CLR}":POKE53281,0:POKE53280,0:PRINTCHR$ (14)

	119



	5	Arcade-Style Games

	160 GOSUB590 170 PRINT"{3 DOWN}{11 SPACES}{RVS}LOADING {SHIFT-SPACE}CHARACTERS" 180 POKE56334,(PEEK(56334)AND254):POKE1,PEEK(1)AND 251 190 FORA=0TO2047:POKE(A+12288),PEEK(A+53248):NEXT 200 FORA=12552T012672 210 READD 220 IFD<>-1THENP0KEA,D:NEXT 230 FORA=12288T014335: READD: IFDO-1THENPOKEA, PEEK ( A):NEXT 240 FORA=12504TO12527:READD:POKEA,D:NEXT 250 P0KE1,55 260 POKE56334,PEEK(56334)ORl 270 GOSUB750:PRINT"{UP}{10 SPACES}INSTRUCTIONS {OFF} {RVS}Y{OFF} OR {RVS}n{OFF} " 280 GETA?:IFA$=""THENPOKE56079,INT(RND(1)7+l):POK E56084,INT(RND(1)7+1):GOTO280 290 IFA$="Y"THENPOKE53272_/(PEEK(53272)AND240)+12:G OSUB380 300 GOTO1000 310 DATA24,24,60,126,24,24,126,255,1,19,51,255,255 ,51,19,1,128 315 DATA200,204,255,255,204,200 320 DATA128,255,126,24,24,126,60,24,24,24,24,60,24 ,60,126,219,195 325 DATA3,7,44,254,254,44,7,3 330 DATA192,224,52,127,127,52,224,192,195,219,126, 60,24,60 335 DATA24,24,16,8,16,8,16,8,16_/8 340 DATA145,74,44,113,142,52,82,137,0,0,0,170,85,0 ,0,0,-1 350 DATA0,0,0,119,68,116,20,119,0,0,0,119,85,87,86 ,117,0,0,0,112,64,96,64,112 360 DATA0,0,0,206,170,206,170,202,0,0,0,238,136,23 6,40,238,0,0,0 365 DATA224,128,224,32,224,-1 370 DATA0,0,0,206,170,202,170,206,0,0,0,139,218,17 1,138,139,0,0,0 375 DATA56,160,56,136,56 380 PRINT"{CLR}{RED}WELCOME TO CYLON ZAP" 390 PRINT"YOU HAVE A BASE NAMED ALPHA"{10 SPACES}: PRINT 400 PRINT"{CYN}YOUR MISSION IS TO{2 SPACES}PROTECT THE":PRINT"NUCLEAR REACTOR" 410 PRINT"{PUR}FROM THE KAMIKAZE STAR ":PRINT" FIG HTERS" 420 PRINT"{DOWN}{GRN}YOU HAVE 4 LASERS{2 SPACES}CO NTROLLED BY THE{4 SPACES}JOYSTICK"

	120



	Arcade-Style Games

	430 PRINT"{BLU}YOU ALSO HAVE SMART BOMBS LAUNCHED {SPACE}BY THE FIRE BUTTON" 440 PRINT"{DOWN}{YEL}ALL YOU DO IS POINT THE GUN A ND THE{6 SPACES}LASER FIRES AUTOMATICALLY" 450 GOSUB500 460 PRINT"{CLR}{PUR}{DOWN}THE FIGHTERS WILL FLY FA STER THE MORE{3 SPACES}OF THEM YOU DESTROY " 470 PRINT"{DOWN}{YEL}BONUS BASE AND BOMB AT 60 POI NTS" 480 PRINT"{BLU}{DOWN}{9 SPACES}{RVS}GOOD LUCK":GOS UB500:RETURN 500 A$="{RVS}" 510 FORL=1TO1000 520 PRINT"{HOME}" 530 PRINTTAB(2)A$;"{CYN}{20 DOWN}HIT RETURN TO CON 540 GETR$:IFR$=CHR$(13)THENRETURN 550 F0RI=1T033 3:NEXT 560 IFA$="{RVS}"THENA$="{OFF}":GOTO580 570 IFA$="{OFF}"THENA$="{RVS}":GOTO580 580 NEXTL 590 A$="{RED}*** {3 SPACES} {4 SPACES}** {2 SPACES}{2 SPACES}":X=LEN(A$):Z$="{DOWN}": GOSUB710 600 A$="{4 SPACES} {2 SPACES}{4 SPACES}* * {2 SPACES}** ":X=LEN(A?):Z$="{2 DOWN}":GOSUB7 10 610 A$="{5 SPACES}{3 SPACES}{4 SPACES}* * {2 SPACES}* *":X=LEN(A$):Z?="{3 DOWN}":GOSUB7 10 611 A$="{5 SPACES}{3 SPACES}{4 SPACES}* * {2 SPACES}* ":X=LEN(A$):Z$="{4 DOWN}":GOSUB7 10 620 A$="{3 SPACES}{3 SPACES}*{2 SPACES}* {2 SPACES}{2 SPACES} ":X=LEN(A$):Z$=" {5 DOWN}":GOSUB710 630 A$="{YEL}{2 SPACES}*{2 SPACES}{2 SPACES} *{2 SPACES} {2 SPACES}":X=LEN(A$):Z$=" {8 DOWN}":GOSUB710 640 A$="{4 SPACES}{2 SPACES}* {2 SPACES} * {2 SPACES}* {3 SPACES}":X=LEN(A$):Z$=" {9 DOWN}":GOSUB710 650 A$="{3 SPACES}{3 SPACES}*{2 SPACES}* {2 SPACES}* {3 SPACES}":X=LEN(A$):Z$=" {10 DOWN}":GOSUB710 660 A$="{2 SPACES}{4 SPACES}* {2 SPACES} {10 SPACES}^M:X=LEN(A$):Z$="{11 DOWN}":GOSUB710

	121



	^^ Arcade-Style Games

	670 A$="{2 SPACES}**{2 SPACES} {2 SPACES} {4 SPACES}* {2 SPACES}":X=LEN(A$):Z$=" {12 DOWN}":GOSUB710 680* PRINT:PRINT 700 GOTO170 710 S=54272 711 POKE54296,15 :POKE54277,18:POKE54278,240 712 POKE 54276,33 720 FORI=lTOLEN(A$):POKE54273,1+40 721 PRINT"{HOME}{DOWN}{8 RIGHT}"Z$;SPC(X)LEFT$(A?, I):POKE54272,(l*2)+180 730 X=X-1:NEXT:FORG=l5TO0STEP-1:POKE54296,G:NEXT:P OKES+4,16 7 35 FORE=STOS+28:POKEE,0:NEXT:RETURN 750 FORA=49152T049453 760 READD 770 POKEA,D 780 NEXT 790 RETURN 800 DATA169,12,141,33,208,169,147,32,210,255,162,8 ,160,16,32,240,255,169,18,32 810 DATA210,255,169 820 DATA169,32,210,255,169,127,32,210,255,169,146, 32,210,25 5,169,32,32,210 825 DATA 255,169,18,32 830 DATA210,255,169,169,32,210,255,169,127,32,210, 255,24,162,9,160,15,32 835 DATA 240,255,169,169 840 DATA32,210,255,169,160,162,5,32,210,255,202,22 4,0,208,248,169,127 845 DATA 32,210,255,24 850 DATA162,10,160,15,32,240,255,169,146,32,210,25 5,169,127,32,210,255 855 DATA 169,18,32,210,255 860 DATA169,160,162,5,32,210,255,202,224,0,208,248 ,169,146,32,210,255 865 DATA 169,169,32,210,255 870 DATA24,162,11,160,15,32,240,255,169,32,32,210, 255,169,18,32,210 875 DATA255,169,160,162,5,32 880 DATA210,2 55,202,224,0,208,248,169,146,32,210,2 5 5,169,32,3 2,210,255,24 885 DATA 24,162,11,160,7 890 DATA32,240,255,169,18,32,210,255,24,162,12,160 ,15,32,240,255,169,169 895 DATA 32,210,255,169 900 DATA160,162,5,32,210,2 55,202,224,0,208,248,169 ,127,32,210,255,24 905 DATA 162,13,160,15,32,240

	122



	Arcade-Style Games

	910 DATA255,169,146,32,210,255,169,127,32,210,255, 169,18,32,210,255 915 DATA 169,160,162,5,32,210 920 DATA255,202,224,0,208,248,169,146,32,210,255,1 69,169,32,210,255,24 925 DATA 169,146,32,210 930 DATA255,24,162,14,160,16,32,240,255,169,127,32 ,210,255,169,169,32 935 DATA 210,255,169,32,32 940 DATA210,255,169,127,32,210,255,169,169,32,210, 255,24,96 1000 RESTORE:CLR 1060 DEFFNA(A)=INT(RND(1)X+A):TT=1482 1070 POKE53272,(PEEK(53272)AND240)+12 1080 N1=1042:N2=1922:N3=1464:N4=1502:V1=36876 1090 CS=53281:C=54272:W1=30:W2=20:W3=10:W4=5:W5=1 1100 A1$="D..":A2$=^HU.. ":A3$="D.. ":A4$="C.. ":A5$=" O. ." 1110 POKECS,l:PRINT"{CLR}":GOTO2190 1120 BASE=3:Sl=l:S2=l:S3=l:S4=l:BOM=3:SC=0 1130 POKECS,12:X=15:Y=1:I=40 1140 PRINT"{CLR}{WHT)":POKECS,8 1150 GOSUB1450 1160 PRINT"{HOME}{WHT}SCORE"SC:PRINT"{HOME}{DOWN}B ASES"BA:PRINT"{WHT}BOMBS"BO 1170 J0=15-(PEEK(56321)AND15) 1180 G=42:FB=(PEEK(56321)AND16) 1190 POKETT,102 1200 POKETT+C,INT(RND(l)7+l) 1210 IFJ0=1 THEN1510 1220 IFJ0=2 THEN1570 1230 IFJ0=4 THEN1630 1240 IFJ0=8 THEN1690 1250 IFFB=0ANDBOM>0THEN2590 1260 A1=FNA(1) 1270 A2=FNA(2) 1280 A3=FNA(3) 1290 A4=FNA(4) 1300 IFA1 = 1ANDSK>0THENS1=0: GOSUB2680 1310 IFA2=2ANDS2<>0THENS2=0: GOSUB2680 1320 IFA3=3ANDS3<>0THENS3=0: GOSUB2680 1330 IFA4=4ANDS4<>0THENS4=0: GOSUB2680 1340 IFSl=0ANDPEEK(Nl+40)<>102THENNl=Nl+I:POKEN1+C ,4:POKEN1,40:POKEN1-I,32 1350 IFPEEK(N1+40)=102THENGOSUB2050 1360 IFS2=0ANDPEEK(N2-40)<>102THENN2=N2-I:POKEN2+C ,3:POKEN2,37:POKEN2+I,32 1370 IFPEEK(N2-40)=102THENGOSUB2050 1380 IFS3=0ANDPEEK(N3+1)<>102THENN3=N3+Y:POKEN3+C, 5:POKEN3,39:POKEN3-Y,32

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	5	Arcade-Style Games

	1390 IFPEEK(N3+1)=102THENGOSUB2050 1400 IFS4=0ANDPEEK(N4-1)<>102THENN4=N4-Y:POKEN4+C, 6:P0KEN4,38:P0KEN4+Y,32 1410 IFPEEK(N4-1)=102THENGOSUB2050 1420 IFBASE=0THENGOTO2130 1430 IFSO50THENX=4 1440 GOTO1160 1450 PRINT"{RED}":SYS49152:POKECS_/11 1460 POKE1362+C,1:POKE1362,33:POKE1602+C_/1:POKE160 2,36:POKE1479+C,1:POKE1479,34 1470 POKE1485+C,l:POKE1485,35 1480 POKETT-1,102:POKETT+1,102:POKETT-40,102:POKET T+40,102 1490 POKETT-1+C,1:POKETT+1+C,1:POKETT-40+C,1:POKET T+40+C1 1500 RETURN 1510 POKE54296,15:POKE54273,33:POKE54272,133:POKE5 4277,50:POKE54278,120 1520 POKE54276,129 1530 FORF=1362TO1042STEP-40 1540 IFPEEK(F-40)< >40THENPOKEF+C,1:POKEF,41:FORT=l TO5:NEXT:POKEF,3 2:NEXT 1550 IFPEEK(F-40)=40THENPOKEN1+C,2:POKEN1,42:GOSUB 1830:POKEN1,32:N1=1042:Sl=l 1560 POKE54296,0:POKE1362,33:GOTO1260 1570 POKE54296,15:POKE54273,33:POKE54272,133:POKE5 4277,50:POKE54278,120 1580 POKE54276,129 1590 FORF=1602TO1944STEP40 1600 IFPEEK(F+40)<>37THENPOKEF+C,1:POKEF,41:FORT=l T05:NEXT:POKEF,32:NEXT 1610 IFPEEK(F+40)=37THENPOKE2+C,2:POKEN2,42:GOSUB1 830:POKEN2,32:N2=1922:S2=l-40 1620 POKE54296,0:POKE1602,36:GOTO1260 1630 POKE54296,15:POKE54273,33:POKE54272,133:POKE5 4277,50:POKE54278,120 1640 POKE54276,129 1650 FORF=1479T01464STEP-l 1660 IFPEEK(F-l)< > 39THENPOKEF+C,1:POKEF,43:F0RT=1T 05:NEXT:POKEF,3 2:NEXT 1670 IFPEEK(F-l)=39THENPOKEN3+C,2:P0KEN3,42:G0SUB1 830:POKEN3,32:N3=1464:S3=l 1680 POKE54296,0:POKE1479,34:G0T01260 1690 POKE54296,15:POKE54273,33:POKE54272,133:P0KE5 4277,50:POKE54278,120 1700 POKE54276_#129 1710 FORF=1485TO1502 1720 IFPEEK(F+l)<>38THENPOKEF+C,1:POKEF,43:F0RT=1T 05:NEXT:POKEF,32:NEXT

	124



	Arcade-Style Games	5

	1730 IFPEEK(F+l)=38THENPOKEN4+C,2:P0KEN4,42:G0SUB1 830:POKEN4,32:N4=l502:S4=l 1740 POKE54296,0:POKE1485,35:GOTO1260 1745 FORS0=54272TO54272+28:POKES0,0:NEXT 1750 POKE54296_/15:POKE54277,53:POKE54278,69:POKE54 276,33 1770 RESTORE:F0RGB=1T012:READHA,LA,DU:POKE54273,HA :POKE54272,LA 1780 FORT=lTODU:NEXTT 1790 NEXTGB:FORS0=54272TO54272+28:POKES0,0:NEXT 1800 RETURN 1810 DATA217,200,213,200,223,200,227,100,234,100,2 30,200 1820 DATA227,100,234,100,230,200,223,200,227,200,2 17,200,213,300,-1 1830 POKE54296,15:POKE54277,53:POKE54278,67:POKE54 276,129 1840 POKE54272,200:POKE54273,33 1850 FORL=15TO0STEP-1 1860 POKE54296,L 1870 NEXT:POKE54276,0 1880 SC=SC+1 1890 IFSC=30THENX=INT(X/2):Y=2 1900 IFSC=50THENX=4:1=80:BOM=BOM+l 1910 IFSC=60ORSC=110ORSC=150THENGOTO1930 1920 RETURN 1930 PRINT"{CLR}{10 DOWN}{10 SPACES}BONUS"; 1940 PRINT" BASE - BOMB":L=0 1950 POKE54296,15:POKE54277,50:POKE54278,167:POKE5 4276,17 1960 FORT=1TO10 1970 POKE54272,230:POKE54273,33 1980 NEXT 1990 FORT=1TO10 2000 POKE54272,180:POKE54273,28 2010 NEXT 2020 IFL<6THENL=L+1:GOTO1950 2030 FORD=54272T054272+28:POKED,0:NEXT 2040 BOM=BOM+l:BA=BA+1:SC=SC+5:PRINT"{CLR}":GOSUBl 450:GOTO1890 2050 POKE54296,14:Ql=1482:Q2=1484:Q3=1522:Q4=1524: K=0:Q5=Q1-41:Q6=Q3+41:Q7=Ql+39 2060 Q8=1526:POKE54277,44:POKE54278,56:POKE54276,1 29 2070 POKE54272,200:POKE54273,34:KK=8 2080 FORZ=15TO0STEP-2 2090 POKE54296,Z:GOSUB2260:NEXT:POKECS,8:POKE54276 ,0

	125



	^% Arcade-Style Games

	2100 N1=1042:S1=1:N2=1922:S2=1:N3=1464:S3=1:N4=150 2:S4=1:PRINT"{CLR}" 2110 BASE=BASE-1:IFBASE<>0THENGOSUB1450 2120 RETURN 2130 PRINT"{CLR}" 2140 IFSC=>W1THENA5$=A4$:A4$=A3$:A3$=A2$ 2150 IFSC=>W1THENA2$=A1$:W5=W4:W4=W3:W3=W2:W2=W1:W 1=SC:GOTO2730 2154 REM LINE 2155 MUST BE ENTERED USING KEYWORD A BBREVIATIONS 2155 IFSC>=W2ANDSC<W1THENA5$=A4$:A4$=A3$:A3$=A2$:W 5=W4:W4=W3:W3=W2:W2=SC:GOT02 740 2160 IFSC=>W3ANDSC<W2THENA5$=A4$:A4$=A3$:W5=W4:W4= W3:W3=SC:GOTO2750 2170 IFSC=>W4ANDSC<W3THENA5$=A4?:W5=W4:W4=SC:GOT02 760 2180 IFSC=>W5ANDSC<W4THENW5=SC:GOTO2770 2190 GOSUB2510:PRINT" {HOMEHbLK} {21 DOWN} {12 SPACESjTO PLAY HIT {RVS}{BLK}Y" 2200 GETZ$:IFZ$=""THENFORCC=55312T055315:POKECC,IN T(RND(1)7+1):NEXT 2210 POKE56165,INT(RND(l)7+l) 2220 IFZ$=""THEN2200 2230 IFZ$="Y"THEN1120 2240 IFZ$="N"THENPRINT"tCLR}iBLU}":POKECS,27:END 2250 GOTO2190 2260 K=K+1:M=41:N=40:0=39:R=INT(RND(1)7+l) 2270 IFK>3ANDK<110THENPOKECS,KK:KK=KK+31 2280 P0KEQ1,G:P0KEQ2,G:P0KEQ3,G:P0KEQ4 _#G:P0KEQ5,G: P0KEQ6,G:P0KEQ7,G:P0KEQ8,G 2290 P0KEQ1+C,R:P0KEQ2+C, INT ( RND (1 ) 7+l ) .-P0KEQ3+C, R:P0KEQ4+C,INT(RND(1)* 7 + 1) 2300 POKEQ5+C,R:POKEQ6+C,INT(RND(l)7+l):P0KEQ7+C, R:P0KEQ8+C,INT(RND(1)7+l) 2310 FORT=1TO10:NEXT 2320 IFK>3THENG=46:PRINT"{CLR}" 2330 IFK<8THENQ1=Q1-0:Q2=Q2-M:Q3=Q3+0:Q4=Q4+M:Q5=Q 5-N:Q6=Q6+N:Q7=Q7-l:Q8=Q8+1 2 340 RETURN 2350 PRINT"{CLR}":RETURN 2360 PRINT"{3 DOWN}":CH=1160:E=l 2370 J0=15-(PEEK(56321)AND15) 2380 FB=PEEK(56321)AND16 2390 IFJ0=8THENE=E+1 2400 IFJ0=4THENE=E-1 2410 IFE=0THENE=26 2420 IFE=27THENE=1 2430 P0KECH,E:P0KECH+C_#7 2440 FORT=1TO100:NEXT

	126



	Arcade-Style Games	5

	2450 P0KECH+C,1 2460 IFFB=0 ANDCH=1160THENNl$=CHR$(E+64):CH=CH+1:E =1:GOTO2370 2470 IFFB=0ANDCH=1161THENN2$=CHR$(E+64) :CH=CH+1:E= 1:GOTO2 3 70 2480 IFFB=0 ANDCH=1162THENN3?=CHR$(E+64):CH=CH+1:E =32:GOTO2370 2490 IFCH=1163THENN5$=N1$+N2$+N3$:RETURN 2500 GOTO2370 2510 POKE53281,l 2 515 REM THE NEXT LINE MUST BE ENTERED USING KEYWO RD ABBREVIATIONS 2520 PRINT"{CLR}{2 SPACES}{BLR}{9 SPACESjCYLON ZAP HEROS":PRINT:PRINT"{RED}{12 SPACES}BEST 5 SC ORES{OFF}" 2530 PRINT"{HOME}{DOWN}{BLK}{4 D0WN}{14 SPACES}"Al $"..."Wl 2540 PRINT"{BLU}{2 D0WN}{14 SPACES}"A2$"..."W2 2550 PRINT"{GRN}{2 D0WN}{14 SPACES}"A3$"..."W3 2560 PRINT"{PUR}{2 DOWN}{14 SPACES}"A4?"..."W4 2570 PRINT"{RED}{2 DOWN}{14 SPACES}"A5$"..."W5 2 580 RETURN 2 590 POKE54296, 15 :POKE5427 7,43:POKE542 78,7 3:POKE54 276,129 2600 FORCO=127T08STEP-17 2610 POKECS,CO 2620 FORT=1TO100:NEXT:NEXTCO:POKECS,11 2630 IFS1=0THENSC=SC+1:GOSUB1890:POKEN1,32:N1=1042 :S1 = 1 2640 IFS2=0THENSC=SC+1:GOSUB1890:POKEN2,32:N2=1922 :S2 = 1 2650 IFS3=0THENSC=SC+1:GOSUB1890:POKEN3,32:N3=1464 :S3 = 1 2660 IFS4=0THENSC=SC+1:GOSUB1890:POKEN4,32:N4=1502 :S4=1 2670 FORS0=54272TO5427 2+28:POKES0_#0:NEXT:BOM=BOM-1 :GOTO1260 2680 S=5427 2:FORE=STOS + 28:POKEE,0:NEXT 2690 POKE54296, 15 :POKE54277, 51 :POKE54278, 84 2700 POKE 54276, 17 :FORJ=1TO40STEP4:POKE 54273,J: POKE54272,255-J-25:NEXT 2710 FORT=lTO 100 :NEXT:POKE54276, 32:F0RT=1T0 50: NEXT 2 720 FORE=STOS+28:POKEE,0:NEXT:RETURN 2730 PRINT"{HOMEjNUMBER 1 ENTER YOUR INITIALS":GOS UB1745:GOSUB2 360:A1$=N5$:GOTO2190 2740 PRINT"{HOME}NUMBER 2 ENTER YOUR INITIALS":GOS UB1745:GOSUB2 360:A2$=N5$:GOTO2190

	127





	5	Arcade-Style Games

	2750 PRINT"{HOME}NUMBER 3 ENTER YOUR INITIALS":GOS UB1745:GOSUB2 360:A3$=N5$:GOTO2190 2760 PRINT"{HOME}NUMBER 4 ENTER YOUR INITIALS":GOS UB1745:GOSUB2360:A4$=N5$:GOTO2190 2770 PRINT"{HOME}NUMBER 5 ENTER YOUR INITIALS":GOS UB1745:GOSUB2 360:A5$=N5$:GOTO2190

	128



	5 Laser Gunner Gary R. Lecompte 64 Translation by Philip I. Nelson____________________

	This arcade-style game achieves an impressive graphics animation without the use of any machine language. "Laser Gunner" is an arcade-type action game. The player controls a laser gun which moves up and down on the left of the screen behind a force field and fires at invading enemy spaceships. The invaders also fire lasers and attempt to open holes in the force field. Every hit weakens the force field until an entire hole is made. A hit through a hole ends the game. Laser Gunner is an example of animation accomplished without the use of machine language routines. The drawback of this type of programming is obvious. Only one string may be animated at a time with any speed. However, by working your game format around this limitation, you can still make action games fast and challenging. The animation of the laser gun and the position of laser fire, as well as the location of the invaders, are controlled by the location routines. The row and column values are POKEd into memory locations 214 and 211. A PRINT statement following these routines will print that string beginning at the location determined by the row and column values. Changing the row and column values and printing the same string again accomplishes animation. The force field changes are made by PEEKing the location of the hit, determining the character at that location, and POKEing the value of the next character to that location. Invader explosions are done by coding cursor movements and printing characters from the invader string. Sound routines are intermixed with laser and explosion routines. This assures that animation and sound will blend. Invader ship location and laser fire are determined by randomizing routines. Skill level is provided by giving the player a minimum preset delay. Actual time before invader laser blasts is always unpredictable.

	129



	"^ Arcade-Style Games Stars are created with simple POKE statements to predetermined locations. All routines are placed in order of importance, with those used most at the beginning. This allows for the fastest program execution possible to increase animation speed. REM statements should be deleted for best effect. The key to speed is simplicity. The shorter the program statements, the greater the speed. Changing the Shapes It is possible to change the shape of the ships. Lines 85 and 86 contain the statements which produce the shape. To make your own ships, you can use any graphic symbols from the front of the 64 keyboard. Pick the characters you want, and substitute them for the shifted characters within the quotes for IN$, Gl$ and G2$ in lines 85 and 86. Remember, you get the left-side graphic character by holding down the Commodore key rather than SHIFT. Laser Gunner 5 POKE53280,0:P0KE53281,0:GOSUB190:PRINT"{CLR}":GO T085 10 POKEROW,X:POKECOL,Y:PRINT^M{UP}^M;:RETURN 11 POKEROW,A:POKECOL,B:PRINT"{UP}";:RETURN 12 POKEROW,Z:POKECOL,B:PRINT"{UP}";:RETURN 13 GOSUB10:PRINTG1$; 14 GOT038 16 TT=TT+1:R=1+INT(RND(1)10):IFTT>TDTHENIFR=10GOT 043 18 IFPEEK(197)=6THEN29 19 IFPEEK(197)=5THEN23 20 IFPEEK(197)=3THEN26 21 G0T016 23 X=X-1:IFX<1THENX=1 24 GOSUB10:PRINTG1$;:GOTOl6 26 X=X+1:IFX>21THENX=21 27 GOSUB10:PRINTG2$;:G0T016 29 GOSUB180 30 X=X+1:Y=3:GOSUB10:F0RI=1T0185STEP5:PRINT"{PUR}> ";:NEXT::GOSUB10 31 F0RI=1T037:PRINT" ";:NEXT:X=X-1:Y=0 33 IFX+1=ATHEN60 34 IFX+1=A+1THEN60 35 IFX+1=A+2THEN60 36 G0T016 38 A=1+INT(RND(1)21):IFA<3THENA=3 39 IFA>19THENA=19 41 G0SUB11:PRINTIN$:G0T016

	130



	Arcade-Style Games	5

	43 GOSUB170:Z=A+1:B=B-1:GOSUB12:FORI=1TO72STEP2:PR INT" {RED}<-{2 LEFT}";: NEXT 45 PRINT"{RIGHT}{UP}N{2 DOWN}{LEFT}M":GOSUBl2:FORI =1T036:PRINT" {2 LEFT}";:NEXT:PRINT"{RIGHT}{UP} {2 DOWN}{LEFT} ":B=B+1 47 HT=SR+((Z-l)40):RD=PEEK(HT) 48 IFRD=160THENRN=1:GOTO57 49 IFRD=231THENRN=2:GOT057 50 IFRD=234THENRN=3:GOT057 51 IFRD=246THENRN=4:GOT057 52 IFRD=97THENRN=5:GOT057 53 IFRD=117THENRN=6:GOT057 54 IFRD=116THENRN=7:GOT057 55 IFRD=101THENRN=8:GOTO57 56 IFRD=32THENRN=8:GOT068 57 FORI=lTORN:READFE:NEXT:POKEHT,FE:RESTORE:GOT016 58 DATA 231,234,246,97,117,116,101,32 60 gosubll:print"{red}{2 left}«{up}{yel}+{2 down} {3 left}{down}{2 left}&3{down}{rvs}£" 61 fori=1to20:next:gosub11:print"{2 left} {up} {2 down}{3 left}{down}{2 left} {down} " 62 gosubll:print"{2 up}{left}£{2 down}{3 left} {red}m{yel}t{2 down} {3 left} {yel}<-{down} {left} {downT{left}" 63 fori=1to20:next:gosub11:print"{2 up}{left} {2 down}{3 left}{2 spaces}{2 down}{3 left} {down}{left}{down}{left}":gosub160 64 fori=1to20:next 65 gosub11:print" {left}{down} {left}{down} {left} {down}":gosub77 67 sc=sc+1:tt=0:goto38 68 fori=1to500:next 70 print"{clr}{wht}{3 down}{10 spaces}you hit";sc; "invaders":gosub170:gosub170:gosub160 71 gosub160:gosub160:gosub160:print"{3 down} {14 spaces}try again?{3 spaces}" 72 gosub170:gosub160:getc$:ifc$=""then72 73 IFC$<>"Y"ANDC$o"N"THEN72 74 IFC$="N"THENPRINT"{CLR}":END 75 SC=0:GOTO123 76 REM-----GENERATE STARS----------- 77 SR=SR-2:P=46 78 POKESR+15,P:POKESR+28,P:POKESR+127,P:POKESR+158 ,P:POKESR+17 5,P:POKESR+2 26,P 79 POKESR+330,P:POKESR+460,P:POKESR+474,P:POKESR+3 90,P:POKESR+5 7 5,P 80 POKESR+605,P:POKESR+628,P:POKESR+703,P:POKESR+7 15,P:POKESR+730,P

	131



	5	Arcade-Style Games

	81 pokesr+806,p:pokesr+819,p:pokesr+83 7,p:pokesr+8 68,p:pokesr+883,p 82 pokesr+904,p:pokesr+928,p:pokesr+947,p:pokesr+9 64, p:pokesr+992,p 83 sr=sr+2:return 84 rem-------set variables------------ 85 row=214:col=211:x=5:y=.:in$ = "{yel}{rvs}£{down} {left}{rvs}{off}{down}{left}g3{wht}^m:b=39: Gl$="{CYN}{RVS}V{OFF}{DOWN}{LEFT}+{D0WN}{LEFT} {RVS}V{OFF}{DOWN}{LEFT} " 86 G2$=^MTCYN}{UP} {DOWN}{LEFT}{RVS}v{OFF}{DOWN} {LEFT}+{DOWN}{LEFT}{RVS}V{OFF}^M:SR=1026:M=21:I= RND(-Tl) 87 GOSUB77:GOT091 88 REM--------LOCATION ROUTINE-------- 89 POKEROW,M:POKECOL,Y:PRINT"{UP}";:RETURN 90 REM-------TITLES TO 118----------- 91 M=M-l:GOSUB89:PRINTGl$; 92 IFM>7THEN91 93 FORI=1TO200:NEXT:GOSUB89 94 PRINT"{DOWN}{2 RIGHT}";:FORI=1TO110STEP10:PRINT "{GRN}>";:NEXT:PRINT"{RVS} LASER GUNNER {OFF}"; 95 GOSUB180:FORI=1TO120STEP10:PRINT">";:NEXT 96 GOSUB89:PRINT"{DOWN}{2 RIGHT}";:F0RI=1T011:PRIN T" ";:NEXT:PRINT"{14 RIGHT}"; 97 F0RI=1T012:PRINT" ";:NEXT:GOSUB160 98 GOSUB89:M=M+1:PRINT"{DOWN}"G2$; 99 IFM<12THEN98 100 GOSUB89:PRINT"{DOWN}{2 RIGHT}";:FORI=1TO200:NE XT 101 FORI=1TO170STEP10:PRINT"{RED}>";:NEXT:GOSUB170 :PRINT"{PUR}AN"; 102 FORI=1TO170STEP10:PRINT"{RED}>";:NEXT:GOSUB170 103 GOSUB89:PRINT"{DOWN}{2 RIGHT}";:F0RI=1T017:PRI NT" ";:NEXT:PRINT"{2 RIGHT}";:F0RI=1T017 104 PRINT" ";:NEXT 105 GOSUB89:M==M+l: PRINT "{DOWN} "G2$; 106 IFM<16THEN105 107 GOSUB89:PRINT"{DOWN}{2 RIGHT}";:FORI=1TO200:NE XT 108 FORI=lTOl12STEP10:PRINT"{PUR}>";:NEXT:GOSUBl70 :PRINT"{YEL}ACTION GAME"; 109 F0RI=1T0110STEP10:PRINT"{PUR}>";:NEXT:GOSUBl70 110 GOSUB89:PRINT"{DOWN}{2 RIGHT}";:F0RI=1T012:PRI NT" "; .-NEXT : PRINT "{11 RIGHT}"; 111 F0RI=1T013:PRINT" ";:NEXT 112 GOSUB89:M=M+1:PRINT"{DOWN}"G2$; 113 IFM<22THEN112 114 GOSUB89:PRINT"{DOWN}{2 RIGHT}";:FORI=1TO200:NE XT

	132



Arcade-Style Games				5

115 116 117 118 119 120 121 122 123	FORI=1TO90STEP10:PRINT"{RED)>";:NEXT:GOSUB180: PRINT"{CYN}{RVS} WANT INSTRUCTIONS?{OFF}"; FORI=1TO100STEP10:PRINT"{RED}>";:NEXT:GOSUB160 GOSUB89:PRINT"{DOWN}{2 RIGHT}";:F0RI=1T09:PRIN T" ";:NEXT:PRINT"{19 RIGHT}"; FORI=1TO10:PRINT" ";:NEXT REM-----WANT INSTRUCTIONS------- GETC$:IFC$=""THENGOSUB170:GOSUB170:GOSUB170:GO SUB160:GOTO114 IFC$="Y"THEN134 REM------PICK SKILL LEVEL--------- PRINT"{CLR}{YEL}{6 DOWN}{5 SPACES}{RVS} {2 SPACES}PICK SKILL LEVEL{5 SPACES}(1-3) {OFF}" GOSUB170:GETC:IFC=0THEN124 IF03THEN124 PRINT"{CLR}{YEL}{6 DOWN}{8 SPACES}{RVS} PRESS {SPACE}[SPACE] TO BEGIN {OFF}" GOSUB160:GETC$:IFC$=""THEN127 IFC=1THENTD=15 IFC=2THENTD=8 IFC=3THENTD=0 REM-----BUILD FORCE FIELD--------- PRINT"{CLR}":GOSUB77:PRINT"{HOME}";:FORI=0TO23 :PRINTTAB(2)"{RVS}{GRN} {OFF}":NEXT:GOT013 REM--------INSTRUCTIONS----------
124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 141 142 143 144 145 146 147 148
	PRINT" {SPACE PRINT" ADERS" PRINT" INTO" PRINT" OY" PRINT" PRINT" FORCE PRINT" D" PRINT" PRINT"	CLR}{DOWN}{2 SPACES}{RVS}{CYN} YOU ARE LASER GUNNER ON A STARSHIP " DOWN} YOU ARE UNDER ATTACK BY ALIEN INV DOWN}{5 SPACES}YOU MUST MOVE YOUR LASER 4 SPACES}POSITION, AND FIRE IT TO DESTR 11 SPACES}THE ALIEN SHIP" 2 DOWN}{3 SPACES}YOU ARE PROTECTED BY A FIELD" 4 SPACES}BUT THE FORCE FIELD IS WEAKENE
		5 SPACES}WITH EVERY HIT BY AN INVADER" 2 DOWN}{5 SPACESjA HIT IN A HOLE ENDS T
	HE GAME"
	PRINT'	2 DOWN}{7 SPACESjTO MOVE UP----HIT
	{RVS} F3 {OFF} KEY" PRINT"{7 SPACES}TO FIRE-{OFF} KEY"		-HIT {RVS} F5
	PRINT"	7 SPACES}TO MOVE DOWN—HIT {RVS} F7
	{OFF} KEY"
	PRINT" NTINUE	2 DOWN}{8 SPACES}{RVS}PRESS SPACE TO CO OFF}"

133



	5	Arcade-Style Games

	149 GETC$:IFC$=^MHTHEN149 150 GOT0123 155 REM--------SOUND SUBROUTINES------- 160 POKEWl,21:POKEW2,129:FORZ=20TOlSTEP-2:POKEHl,Z :POKEL1,Z 161 *POKEH2,INT(RND(1)70)+3:POKEL2,Z:NEXT:POKEWl,0 :POKEW2,0:RETURN 170 POKEWl,17:POKEW2_/129:FORZ=35TO0STEP-7:POKEHl,Z :POKEL1,Z:POKEL2,Z 171 POKEH2,INT(RND(1)70 ) :NEXT:POKEWl,0:POKEW2,0:R* ETURN 180 POKEWl,21:FORZ=1TO3:FORZX=0TO100STEP15:POKEHl, ZX:POKEL1,ZX:NEXT:NEXT 181 POKEWl,0:RETURN 190 POKE54296,15:POKE54277,15:POKE54291,65 :W1=542 76:W2=54290:H1=54273:L1=54272 191 H2=54287:L2=54286:RETURN

	134



	•

		Machine Language Games



	6 Using the Machine Language Editor: MLX

	Charles Brannon

	Three of the games in this chapter are written completely in machine language. The "Machine Language Editor" will make typing a perfect copy of those games a snap. Remember the last time you typed in a long machine language program? You typed in hundreds of DATA statements, numbers, and commas. Even then, you couldn't be sure if you'd typed it in right. So you went back, proofread, tried to run the program, crashed, went back and proofread again, corrected a few typing errors, ran again, crashed, rechecked your typing .... Frustrating, wasn't it? Until now, though, that has been the best way to enter machine language into your machine. Unless you happen to own an assembler and are willing to wrangle with machine language on the assembly level, it is much easier to enter a BASIC program that reads the DATA statements and POKEs the numbers into memory. Some of these BASIC loaders will use a checksum to see if you've typed the numbers correctly. The simplest checksum is just the sum of all the numbers in the DATA statements. If you make an error, your checksum will not match up. Some programmers have made your task easier by creating checksums every ten lines, so you can zero in on your errors. But MLX comes to the rescue! The "Machine Language Editor" (MLX) is a great way to enter all those long machine language programs with a mininum of fuss. MLX lets you enter the numbers from a special list that looks similar to BASIC DATA statements. It checks your typing on a line-by-line basis. It won't

	137



	J% Machine Language Games let you enter illegal characters when you should be typing numbers. It won't let you enter numbers greater than 255. It will prevent you from entering the wrong numbers on the wrong line. In short, MLX will make proofreading obsolete. Boot Disks In addition, MLX will generate a ready-to-use tape or disk file. You can then use the LOAD command to read the program into the computer, just like any other program. Specifically, you enter: LOAD "program", 1,1 (for tape) or LOAD "program", 8,1 (for disk) To start the program, you need to enter a SYS command that transfers control from BASIC to machine language. The starting SYS will always be given in the appropriate article. Using MLX Type in and save MLX (you'll want to use it in the future). When you're ready to type in the machine language program, RUN MLX. The program will ask you for two numbers: the starting address and the ending address. Below is a table that lists this information for each of the games that use MLX. Starting and Ending Addresses Game Start address End address Command to Run Munchmaze 12288 13956 SYS 12311 Richthofen's 2049 5817 RUN or SYS 2063 Revenge ZuiderZee 49152 52040 Once you have entered the starting and ending addresses, you'll get a prompt to start entering the data. The prompt is the current line you are entering from the listing. Each line is six numbers plus a checksum. If you enter any of the six numbers wrong, or enter the checksum wrong, the 64 will ring the buzzer and prompt you to reenter the line. If you enter it correctly, a pleasant bell tone will sound, and you go on and enter the next line. A Special Editor You are not using the normal Commodore 64 editor with MLX. For example, MLX will accept only numbers as input. If you need to make a correction, press the <INST/DEL> key; the entire

	138



	Machine Language Games	6

	number is deleted. You can press it as many times as necessary to get back to the start of the line. If you enter three-digit numbers as listed, the computer will automatically print the comma and go on to accept the next number. If you enter less than three digits, you can press either the comma, space bar, or RETURN key to advance to the next number. The checksum will automatically appear in inverse video; don't worry—it's highlighted for emphasis. When testing it, I've found it to be extremely easy to enter long listings. With the audio cues provided, you don't even have to look at the screen if you're a touch-typist. When you get through typing, assuming you type it all in one session, you can then save the completed and bug-free program to tape or disk. Follow the screen instructions. If you get any errors while writing, you probably have a bad disk, or the disk was full, or you made a typo when entering the MLX program. (Sorry, it can't check itself.) Command Control What if you don't want to enter the whole program in one sitting? MLX lets you enter as much as you want, save the whole schmeer, and then reLOAD the file from tape or disk when you want to continue. MLX recognizes these few commands: SHIFT-S: Save SHIFT-L: Load SHIFT-N: New Address SHIFT-D: Display Hold down SHIFT while you press the appropriate key. You will jump out of the line you've been typing, so I recommend you do it at a new prompt. Use the Save command to save what you've been working on. It will write the tape or disk file as if you've finished, but the tape or disk won't work, of course, until you finish the typing. Remember what address you stop on. The next time you RUN MLX, answer all the prompts as you did before, then insert the disk or tape. When you get to the entry prompt, press SHIFT-L to reLOAD the file into memory. You'll then use the New Address command to resume typing. New Address and Display After you press SHIFT-N, enter the address where you previously stopped. The prompt will change, and you can then continue typing. Always enter a New Address that matches up with one of the line numbers in the special listing, or else the checksum won't

	139



	y% Machine Language Games match up. You can use the Display command to display a section of your typing. After you press SHIFT-D, enter two addresses within the line number range of the listing. You can abort the listing by pressing any key. Tricky Stuff The special commands may seem a little confusing, but as you work with MLX, they will become valuable. For example, what if you forgot where you stopped typing? Use the Display command to scan memory from the beginning to the end of the program. When you see a bunch of 170s, stop the listing (press a key) and continue typing where the 170s start. Some programs contain many sections of 170s. To avoid typing them, you can use the New Address command to skip over the blocks of 170s. Be careful, though; you don't want to skip over anything you should type. You can use the Save and Load commands to make copies of the completed game. Use the Load command to reLOAD the tape or disk, then insert a new tape or disk and use the Save command to create a new copy One quirk about tapes made with the Save command: when you load them, the message "FOUND program" may appear twice. The tape will load just fine, however. Programmers will find MLX an interesting program, in protecting the user from mistakes. There is also some screen formatting. Most interesting is the use of ROM Kernal routines for LOADing and SAVEing blocks of memory. Just POKE the starting address (low byte/high byte) into 251 and 252, and POKE the ending address into 254 and 255. Any error code can be found in location 253 (an error would be a code less than ten). I hope you will find MLX to be a true labor-saving program. Since it has been tested by entering actual programs, you can count on it as an aid for generating bug-free machine language. MLX 100 PRINT"{CLR}{RED}";CHR$(142);CHR$(8);:POKE53281 ,1:POKE53280,1 101 POKE 788,52:REM DISABLE RUN/STOP 110 PRINT^m{RVS}{40 SPACES}"; *120 PRINT"{RVS}{15 SPACES}{RIGHT}{OFF}B3£{RVS} {RIGHT} {RIGHT}{2 SPACES}&§{OFF}l%£ {RVS}£{RVS}{13 SPACES}"; 140**



	Machine Language Games	6

	130 PRINT"{RVS}{15 SPACES}{RIGHT} £g3{RIGHT} *{2 RIGHT} {OFF}£{RVS}£i3{OFF}B3{RVS}* {13 SPACES}"; 140 PRINT"{RVS}{40 SPACES}" 150 V=53248:POKE2040,13:POKE2041,13:FORI=832TO894: POKEI,255:NEXT:POKEV+27,3 160 POKEV+21,3:POKEV+39,2:POKEV+40,2:POKEV,144:POK EV+1,54:POKEV+2, 192:POKEV+3,54 170 POKEV+29,3 180 FORI=0TO23:READA:POKE679+1,A:POKEV+39,A:POKEV+ 40,A:NEXT 185 DATA169,251,166,254,164,255,32,216,255,133,253 ,96 187 DATA169,0,166,251,164,252,32,213,255,133,253,9 6 190 POKEV+39,7:POKEV+40,7 200 PRINT"{2 DOWN}{PUR}{BLK}{3 SPACES}A FAILSAFE M ACHINE LANGUAGE EDITOR{5 DOWN}" 210 PRINT"g53{2 UPjSTARTING ADDRESS?{8 SPACES} *{9 LEFT}";:INPUTS:F=1-F:C$=CHR$(31+119F) 220 IFS<256OR(S>40960ANDS<49152)ORS>53247THENGOSUB 3000 2GOTO210 225 PRINT:PRINT:PRINT 230 PRINT"i53{2 UPjENDING ADDRESS?{8 SPACES} {9 LEFT}";:INPUTE:F=1-F:C$=CHR$(31+119F) 240 IFE<256OR(E>40960ANDE<49152)ORE>53247THENGOSUB* 3000:GOTO230 250 IFE<STHENPRINTC$;"{RVS}ENDING < START {2 SPACES}":GOSUBl000:GOTO 230 260 PRINT:PRINT:PRINT 300 PRINT"{CLR}";CHR$(14):AD=S:POKEV+21,0 310 PRINTRIGHT?("0000"+MID$(STR$(AD),2),5);":";:FO RJ=1T06 320 GOSUB570:IFN=-1THENJ=J+N:GOTO320 390 IFN=-211THEN 710 400 IFN=-204THEN 790 410 IFN=-206THENPRINT:INPUT"{DOWN}ENTER NEW ADDRES S";ZZ 415 IFN=-206THENIFZZ<SORZZ>ETHENPRINT"{RVS}OUT OF *{SPACE}RANGE":GOSUB1000:GOTO410 417 IFN=-206THENADZZ:PRINT:GOTO310 420 IF NO-196 THEN 480 430 PRINT:INPUT"DISPLAY:FROM";F:PRINT,"TO";:INPUTT 440 IFF<SORF>EORT<SORT>ETHENPRINT"AT LEAST";S;" {LEFT}, NOT MORE THAN";E:GOTO430 450 FORI=FTOTSTEP6:PRINT:PRINTRIGHT$("0000"+MID$(S TR$(I),2),5);":"; 451 FORK=0TO5:N«PEEK(l+K)xPRINTRIGHT$("00"+MID$(ST R$(N),2),3);",";**

	141



	f% Machine Language Games

	460 GETA$:IFA$ >""THENPRINT:PRINT:G0T0310 470 NEXTK:PRINTCHR$(20);:NEXTI:PRINT:PRINT:G0T0310 480 IFN<0 THEN PRINT:GOTO310 490 A(J)=N:NEXTJ *500 CKSUM=AD-INT(AD/256)256:F0RI=1T06:CKSUM=(CKSU M+A(I))AND255:NEXT 510 PRINTCHR$(18);:GOSUB570:PRINTCHR?(20) 515 IFN=CKSUMTHEN530 520 PRINT:PRINT"LINE ENTERED WRONG 2 RE-ENTER"2PRI NT2GOSUB1000 2GOTO310 530 GOSUB2000 540 F0RI=1T06 2 POKEAD+I-1,A(I)xNEXT 2 POKE54272,01POK E54273,0 550 AD=AD+6 2lF AD<E THEN 310 560 GOTO 710 570 N=0 2Z=0 580 PRINT "E-h3"; 581 GETA$2lFA$=""THEN581 585 PRINTCHR?(20);2A=ASC(A$)2IFA=130RA=440RA=32THE N670 590 IFA>128THENN=-A2 RETURN 600 IFA<>20 THEN 630 610 GOSUB690 2lFI=lANDT=44THENN==-l2PRINT"{LEFT} {LEFT}";2GOTO690 620 GOTO570 630 IFA<48ORA>57THEN580 640 PRINTA$;2N=N10+A-48* 650 IFN>255 THEN A=20 2GOSUB10002GOTO600 660 Z=Z+l2lFZ<3THEN580 670 IFZ=0THENGOSUB1000 2GOTO570 680 PRINT",";2 RETURN 690 *S%=PEEK(209)+256PEEK(210)+PEEK(211) 691 F0RI=1T03 2T=PEEK(S%-I) 695 IFT<>44ANDT<>58THENPOKES%-I,32:NEXT 700 PRINTLEFT$("{3 LEFT}",I-1);2 RETURN 710 PRINT"{CLRJlRVS}* SAVE {3 DOWN}"* 720 INPUT"{DOWN} FILENAME";F$ 730 PRINT 2 PRINT"{2 DOWN}{RVS}T{OFF}APE OR {RVSjD *{0FF}ISK2 (T/D)" 740 GETA$ 2IFA$ < >"T"ANDA$ < >"D"THEN740 750 DV=l-7(A$="D")2lFDV=8THENF$="0 2"+F$ 760 OPEN l,DV,l,F$2POKE252,S/256:POKE251,S-PEEK(25 2)256 765 POKE255,E/256_:POKE254_/E-PEEK(255)256 770 POKE253_#10 2SYS 679:CLOSE1:IFPEEK(253)>90RPEEK( 253)=0THENPRINT"{DOWN}DONE."2END 780 PRINT "{DOWN} ERROR ON j>AVE.{2 SPACES} TRY AGAIN. ^M2lFDV=lTHEN720**



	Machine Language Games	6

	781 OPENl5,8,15:INPUT #15,DS,DS $:PRINTDS;DS $:CLOSEl 5:GOTO720 790 PRINT" {CLRHRVS}* LOAD *{2 DOWN}" 800 INPUT"{2 DOWN} FILENAME";F$ 810 PRINT:PRINT"{2 DOWN}{RVS}T{OFF}APE OR {RVS}D *{OFFjlSK: (T/D)" 820 GETA$:IFA$<>"T"ANDA$O"D"THEN820 830 DV=1-7(A$="D"):IFDV=8THENF$="0:"+F$ 840 OPEN 1,DV,0,F$:POKE252,S/256:POKE251,S-PEEK(25 2)256 850 POKE253,10:SYS 691:CLOSEl 860 IFPEEK(253)>9 OR PEEK(253)=0 THEN PRINT:PRINT:* GOTO310 870 PRINT"{DOWN}ERROR ON LOAD.{2 SPACES}TRY AGAIN. {DOWN}":IFDV=1THEN800 880 OPEN15,8,15:INPUT#15,DS,DS$:PRINTDS;DS$:CLOSEl 5:GOTO800 1000 REM BUZZER 1001 POKE54296,15:POKE54277_f45:POKE54278,165 1002 POKE54276,33:POKE 54273,6:POKE54272,5 1003 FORT=1TO200:NEXT:POKE54276,32:POKE54273,0:POK E54272_#0:RETURN 2000 REM BELL SOUND 2001 POKE54296,15:POKE54277,0:POKE54278,247 2002 POKE 54276,17:POKE54273,40:POKE54272,0 2003 FORT=1TO100:NEXT:POKE54276,16:RETURN 3000 PRINTC$;"{RVS}NOT ZERO PAGE OR ROM":GOTO1000



	Munchmaze

	Gary E. Marsa 64 Translation by Gregg Peele

	"Munchmaze" is a fast-action strategy game. Since it is written in machine language, it requires the use of the Machine Language Editor (MLX)for mistake-proof entering. The character in "Munchmaze" hurries through the maze dropping bread crumbs as it goes. You move your character around by using the I, J, K, and M keys trying to munch up as many of the bread crumbs as you can before the character catches you. The game ends when the two characters collide or when you accumulate 10,000 points. There are three speed levels: slow, moderate, and fast. Both characters move at the same speed, but the computer character beats you on the corners. Also, you have to change directions manually; it doesn't. The computer character always goes left if it can; it's helpful to remember this when you are looking for a temporary hiding place. There's another tricky feature, too. Sometimes, when the two characters are moving from opposite directions toward each other, the computer character goes right on by and no collision occurs. Just breathe a sigh of relief and continue munching—you were lucky. The maze in Munchmaze is not constructed on the screen, but in another area of RAM. It is then transferred to the screen, where it appears all at once; then there is a one-second delay before the action begins. If you break out of the program for any reason, just type SYS 12331 and RETURN to restart. Typing in Munchmaze This program is written entirely in machine language, so it is necessary to enter it using the Machine Language Editor (MLX) found at the beginning of this chapter. Be sure to read the directions for using the MLX. The information needed to enter Munchmaze with the MLX is:

	144



	Machine Language Games

	Starting address: 12288 Ending address: 13956 Once Munchmaze is saved to disk or tape, the procedure for loading the program is as follows: From disk: type LOAD "MUNCHMAZE", 8,1 From tape: type LOAD"", 1,1 When the program is loaded into memory, type SYS 12311 to run it.

	Munchmaze 12288 :020,004,010,000,088,178,044 12294 :187,040,171,084,073,041,090 12300 :058,158,049,048,052,056,177 12306 :000,000,000,234,234,169,143 12312 :021,141,024,208,169,000,075 12318 :141,096,010,141,097,010,013 12324 -.169,147,032, 210, 255,169, 250 12330 :007,162,000,157,000,216,072 12336 :157,000,217,157,000,218,029 12342 -.157,000,219,232,208,241,087 12348 .-169,120,141,229,051,169,171 12354 :052,141,230,051,162,031,221 12360 :169,005,032,220,051,169,206 12366 :000,141,098,010,141,099,055 12372 :010,133,162,024,165,161,227 12378 :105,002,133,166,165,161,054 12384 :197,166,208,250,169,147,209 12390 :032,210,255,169,000,162,162 12396 :000,157,000,216,157,000,126 12402 :217,157,000,218,157,000,095 12408 .-219,232,208,241,032,168,196 12414 -.051,162,039,169,160,157,096 12420 -.039,004,157,151,007,202,180 12426 :208,247,169,080,133,168,119 12432 2 169,004,133,169,162,021,034 12438 .-160,000,169,160,145,168,184 12444 :160,038,145,168,032,250,181 12450 :051,202,208,240,169,119,127 12456 :141,229,051,169,053,141,184 12462 :230,051,162,166,169,004,188 12468 .-032,220,051,162,000,169,046 12474 :032,157,000,011,157,000,031 12480 :012,157,000,013,157,000,019 12486 :014,232,208,241,169,081,119

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	Machine Language Games

	12786 :105,176,141,000,004,141,041 12792 :038,004,024,165,162,105,234 12798 :060,133,254,165,162,197,201 12804 :254,208,250,169,081,133,075 12810 :168,133,180,169,004,133,029 12816 :169,133,181,169,001,133,034 12822 :254,162,002,134,165,160,131 12828 :000,169,102,145,168,169,013 12834 :000,133,162,166,165,138,030 12840 :010,168,(^41185,075,052,042 12846 :101,168,rn',170,185,076,lll 12852 :052,101,169,133,171,160,070 12858 :000,177,170,201,160,208,206 12864 :009,202,138,041,003,133,078 12870 :165,076,037,050,201,081,168 12876 :208,003,076,004,051,169,075 12882 :102,145,170,169,058,145,103 12888 :168,165,170,133,168,165,033 12894 :171,133,169,232,138,041,210 12900 :003,133,165,165,254,240,036 12906 :008,160,000,132,254,169,061 12912 :081,145,180,162,000,165,077 12918 :197,221,083,052,240,008,151 12924 :232,224,004,208,246,076,090 12930 :183,050,138,010,168,024,191 12936 :185,075,052,101,180,133,094 12942 :195,185,076,052,101,181,164 12948 .-133,196,160,000,177,195,241 12954 :201,160,240,025,201,058,015 12960 :208,003,032,006,052,160,109 12966 :000,169,081,145,195,169,157 12972 .-032,145,180,165,195,133, 254 12978 -.180,165,196,133,181,165,174 12984 :162,197,166,208,250,173,060 12990 :098,010,201,016,208,061,016 12996 :173,099,010,201,039,208,158 13002 :054,169,081,133,168,169,208 13008 :004,133,169,162,000,160,068 13014 .-000,177,168,201,058,208,002 13020 -.007,032,006,052,169,032,006 13026 .-145,168, 200,192, 037, 208,152 13032 :238,032,250,051,232,224,235 13038 :021,208,228,162,000,189,022 13044 :093,054,240,006,157,051,077 13050 :004,232,208,245,076,127,118 13056 .-051,076,033,050,169,102,225 13062 -.145,170,169,058,145,168,093 13068 .-165,180,133,168,165,181,236 13074 :133,169,056,165,168,233,174

Machine Language Games

13080 13086 13092 13098 13104 13110 13116 13122 13128 13134 13140 13146 13152 13158 13164 13170 13176 13182 13188 13194 13200 13206 13212 13218 13224 13230 13236 13242 13248 13254 13260 13266 13272 13278 13284 13290 13296 13302 13308 13314 13320 13326 13332 13338 13344 13350 13356 13362 13368

:041,133 1000,133 :166,169 :170,133 :181_/169 : 000,162 {087,052 : 008,208 (169,007 (087,052 :003,208 :105,040 :230,181 i201,003 (208,252 :162,000 (006,157 i245,056 :096,010 1099,010 :100,010 (173,098 (173,099 (032,194 (162,000 i006,157 (245,162 ^240,006 5 208,245 :097,010 :221,189 j001,240 :232,208 (133,169 (189,120 :255,240 (232,208 :232,208 ;168,105 (002,230 (152,072 (105,002 (003,238 (181,168 (208,248 (099,010 (221,189 (001,240 (232,208


	,170	rl65,
	,171	rl69,
	,255	rl33,
	,180	rl65,
	,000	,133,
	,000	rl77,
	,240	r005,
	,246	,134,
	,229	r253,
	,145	rl80,
	,224	_r024,
	,133	,180,
	,230	,165,
	,208	,203,
	,198	,166,
	,189	,110,
	,055,	,004,
	,173,	,098,
	,141,	,100,
	,237,	,097,
	,240,	,017,
	,010,	,141,
	,010,	,141,
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	,189,	,095,
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	,162,	000,
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	,162,	000,
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	,012,	145,
	,241,	,032,
	,233,	096,
	,040,	133,
	,169,	096,
	,024,	173,
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	,162,	000,
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240	,133	,108
162	,165	,062
171	,133	,226
165	,160,	,088
180,	,221	,026
232,	,224,	,132
253	,056,	,203
170	,189,	,065
200	,192,	,166
165,	,180,	120
144,	,002,	,182
165,	,165,	208
165,	,162,	020
208,	,179,	039
052	,240,	099
232	,208,	,014
010,	,237,	177
010,	,173,	150
010,	,013,	092
144,	015,	158
096,	010,	166
097,	010,	174
077,	048,	128
052,	,240,	138
232,	,208,	019
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250,	051,	230
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138,	072,	197
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162,	000,	020
224,	008,	143
010,	173,	173
179,	032,	023
189,	000,	037
012,	,004,	214
008,	,104,	247

148



	Machine Language Games

	13374 :149,167,202,208,250,104,118 13380 :168,104,170,096,234,234,050 13386 :234,001,000,216,255,255,011 13392 :255,040,000,037,033,034,223 13398 :036,160,032,058,102,170,132 13404 :186,127,255,019,003,015,185 13410 :018,005,058,032,048,000,003 13416 :008,009,007,008,058,000,194 13422 :135,129,141,133,160,143,183 13428 :150,133,146,000,079,077,189 13434 :032,032,078,080,099,080,011 13440 :032,079,099,079,077,032,014 13446 :079,080,078,099,099,099,156 13452 :077,079,080,032,079,080,055 13458 :000,101,032,077,078,032,210 13464 :103,032,103,032,101,032,043 13470 :101,032,077,101,103,032,092 13476 -.032,079,076,100,101,103,143 13482 :032,101,103,000,101,032,027 13488 :032,032,032,103,032,103,254 13494 :032,101,032,101,032,032,000 13500 :032,103,032,032,101,032,008 13506 :032,101,032,099,032,103,081 13512 :000,101,103,077,078,101,148 13518 :103,032,103,100,101,032,165 13524 :101,103,077,032,103,032,148 13530 :032,076,079,099,101,103,196 13536 :099,101,103,000,076,122,213 13542 :032,032,076,122,077,100,157 13548 :100,100,078,076,122,032,232 13554 :077,122,077,100,100,100,050 13560 :078,076,122,032,076,122,242 13566 :000,000,160,223,032,032,189 13572 :233,231,032,233,160,223,092 13578 :032,160,160,160,160,231,145 13584 :160,160,160,160,160,032,080 13590 :002,025,000,160,160,223,080 13596 :233,160,231,233,160,226,247 13602 :160,223,032,032,233,160,106 13608 :105,160,160,000,160,160,017 13614 :160,160,160,231,160,160,053 13620 :098,160,231,032,233,160,198 13626 :105,032,160,160,160,160,067 13632 :032,032,007,001,018,025,179 13638 .-000,160,160,095,105,160, 238 13644 :231,160,160,226,160,231,220 13650 :233,160,105,032,032,160,036 13656 :160,000,160,160,032,032,120 13662 :160,231,160,160,032,160,229

Machine Language Games


13668	:231	_r160
13674	:160	_r160
13680	:013	_r001
13686	:255	,032
13692	:032	_r032
13698	:022	_r005
13704	:032	,034
13710	:019	,009
13716	:032	,032
13722	:032	,032
13728	:012	,005
13734	:019	,058
13740	:032,	_r032
13746	:060	,067
13752	:032,	032
13758	:013,	015
13764	:016,	000
13770	:032,	,032
13776	:032,	_r061
13782	:005	,032
13788	:000,	,032
13794	:032,	032
13800	:061,	032
13806	:032,	018
13812	:000,	032
13818	:032,	,032
13824	:061,	032
13830	:032,	004
13836	1255,	160
13842	:032,	032
13848	:019,	005
13854	1005,	004
13860	:020,	015
13866	:160,	032
13872	:032,	061
13878	:044,	032
13884	-.013,	015
13890	:020,	005
13896	:061,	032
13902	:000,	000
13908	:032,	032
13914	:032,	032
13920	:016,	018
13926	:145,	032
13932	:021,	009
13938	:153,	143
13944	:160,	129
13950	:146₁	161
13956	:255,	255

,160,160

,018,019

,032,032

,032,020

,081,034

,014,007

,030,032

,020,008

,020,020

,032,032

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009,032

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032,032

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032,032

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032,160

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032,019

032,006

018,058

160,032

006,001

178,032

004,005

044,032

019,012

160,032

032,032

005,019

020,015

020,046

149,167

137,142

161,032

255,255

,160 ,160 ,001 ,009 ,013 ,008 ,032 ,000 ,032 ,005 ,005 ,032 ,000 ,062 ,061 ,032 ,032 ,032 ,015 ,006 ,022 ,011 ,022 ,008 ,013 ,013 ,022 ,014 ,032 ,015 ,016 ,001 ,000 ,032 ,019 ,061 ,018 ,179 ,015 ,160 ,032 ,032 ,019 ,032 ,000 ,146 ,142 ,255 ,255


	231	_r178
	032	,170
	000,	,164
	032,	,254
	015,	,024
	005,	,222
	021,	rH4
	032,	,223
	032,	,082
	032,	,027
	018,	,240
	000,	,083
	010,	115
	011,	014
	032,	126
	021,	042
	093,	145
	010,	,116
	022,	127
	020,	038
	032,	114
	032,	141
	005,	124
	020,	076
	032,	129
	032,	167
	005,	148
	000,	094
	032,	171
	015,	123
	005,	120
	003,	081
	000,	147
	177,	123
	020,	187
	032,	177
	001,	116
	032,	122
	023,	234
	032,	206
	032,	020
	032,	026
	032,	205
	017,	107
	255,	203
	133,	237
	133,	195
	032,	145
	255,	126

150



	6 Richthofen's Revenge________ Chris Metcalf Marc Sugiyama__________________________

	"Richthofen's Revenge" is an arcade-style game that even the most experienced game players will find challenging. This program requires special care to enter correctly; please see the section "Typing in the Program!' The airborne forces of Richthofen, the dreaded Red Baron, have been mobilized. Because of your reputation as a swift pilot and accurate gunner, you have been chosen to defend the front line. Only a few planes are available, with no time to build more. Prepare yourself to meet the hordes of Richthofen. As you encounter each succeeding wave of the enemy, another airplane will be delivered to the front. Once all the planes have been destroyed, however, there will be nothing to stop the enemy from an all-out invasion. Your skills are all that stand between Richthofen's forces and your country Typing in the Program This program is written entirely in machine language, so it should be entered using the Machine Language Editor (MLX) found earlier in this chapter. The steps to typing in a machine language program using MLX are simple, but they must be followed exactly in order to get a playable copy of the game. Once you have a copy of "Richthofen's Revenge" saved on disk or tape, you will be able to LOAD and RUN it just as you would any BASIC program even though it is machine language. The steps for typing in Richthofen's Revenge are: 1. Reset the computer by turning it off, then back on. 2. Type this line: POKE 44,23:POKE 23*256,0:NEW 3. LOAD the Machine Language Editor into memory. (If you have not typed in and SAVEd MLX, you will have to do that first.)

	151



	f% Machine Language Games 4. RUN the MLX program. 5. Answer the prompts START ADDR: 2049 END ADDR: 5817 6. Type in the data. 7. MLX will prompt you for a filename. 8. Before you load the program, reset the computer. That's all there is to it. It is not necessary to type in all the data in one session. The instructions for using MLX are at the beginning of this chapter. If you do decide to enter the data in more than one session, it will be necessary to follow the above steps each time you begin a session. Preparing for Battle When you first RUN the game, the screen will come up with a landscape, a status line, and the message RICHTHOFEN'S REVENGE. The information given in the status line is the high score, the score of the current game, and the number of backup planes remaining. A short tune will play to prepare you for the combat. When the message PRESS FIRE TO BEGIN appears, you may begin playing or move to a higher level. By moving the joystick up or down, you can pick any level from 1 to 30. Levels 31 through 40 are reserved for expert players, and the levels above that are only for the true masters. Once you have selected a level, or at any point after the music begins, you may press the fire button and begin playing. Every time you enter a level, or when a new plane is called up, you begin at the very top of the screen. This area is off-limits to Rich-thofen's forces due to their limited flight ceilings. However, once you go down into their midst, you too are sealed off from this high-altitude bracket for the duration of the level. Your Opponents Richthofen is employing three types of aircraft. Surveillance balloons patrol the areas they have been assigned to in accordance with random wind currents. These have been judged least important by the Air Force (50 points each). The remainder of the enemy forces consists of two types of aircraft: the main attack force, consisting of blue-green planes which always fly west, and the equally important red spy craft. Both types are worth 75 points each. 152



	Machine Language Games

	Some strategies and tips have been given to you by Air Force command. Although your aircraft can dodge mountains and the like without any danger, a number of civilian residences are scat- ( tered throughout the combat area. These present a very definite threat to navigation. You can neither fly nor fire through them. Furthermore, the explosions of the enemy craft are deadly to you. Air Force Briefing The Air Force has also given you a short list of pointers for fighting the enemy. You will find that balloons are often extremely difficult to hit. This problem may be at least partially remedied by the use of the rapid-fire aspect of your controller. Holding down the fire button will cause your machine gun to fire rapidly after a slight initial delay At times you may find yourself flying on and on without encountering any enemy craft. Often the problem is that the few surviving enemy fighter planes are going in the same direction as yourself. In such cases, simply turn and wait for them. To determine how far you are from the end of a level, consult the table below. One final item is of some importance to you as a fighter pilot. The first planes sent out to you were of undeniably high quality and workmanship. The components were all painstakingly hand-formed, and the result was an airplane that could achieve an unusually high speed—enough, in fact, to overtake even the enemy fighter pilots. But as the production of these airplanes increased, the quality declined. Thus as you continue to play, you will find that your planes lose efficiency, until after a number of levels your top speed is barely that of the enemy planes. Several keyboard controls have been included in the program. Pressing f7 causes all game action and sound to stop until the key is pressed again or the fire button pushed. RUN/ STOP has the same effect. F8 ends the program, leaving your country to Richthof en's mercy. F3 turns the sound of your engines on and off, but leaves the noise of shooting and explosions as always. Fl functions as a reset key, checking for a high score then returning you to the initial display. A variety of melodies has been included in the program. All of them may be skipped by pressing the fire button on your joystick.

	153

f% Machine Language Games

Levels of Play


Play	Number	Accumulated
Level	of Enemy	Score
1	12	650
2	16	1650
3	20	2900
4	24	4400
5	24	5900
6	24	7400
7	24	9000
8	28	10800
9	28	12600
10	28	14400
11	28	16300
12	32	18400
13	32	20500
14	32	22700
15	36	25100
16	36	27500
17	36	30000
18	40	32600
19	40	35200
20	40	37700
21	44	39800
22	44	42750
23	44	45550
24	48	48650
25	48	51850
26	48	55100
27	52	58500
28	52	61900
29	52	65450
30	56	69150
31	56	72850
32	56	76650
33	60	80650
34	60	84750
35	60	88850
36	64	93050
37	64	97300
38	64	101350
39	64	105725
40	64	110100
41	64	113300
42	64	118100
43	64	122900
44	64	127275
45	64	130475
etc.

154

Machine Language Games

RichthoferTs Revenge

:013 :050 :000 :133 :221 :141 :032 :178 :208 :169 :014 :141 :035 :157 :162 :015 :079 :000 :176 :160 :000 :245 :153 :208 :164 :168 :040 :164 :200 :000 :002 :141 :033 :220 :169 :017 :208 :016 :016 :169 :169 :173 :004 :002 :141 :136 :255 :169


,008,	100,	000,	158,
,048,	054,	051,	041,
,000,	165,	001,	041,
,001,	169,	197,	141,
,169,	000,	141,	023,
,029,	208,	141,	027,
,006,	017,	169,	003,
,002,	169,	027,	141,
,169,	172,	141,	000,
,011,	141,	032,	208,
/141,	033,	208,	169,
,034,	208,	169,	012,
,208,	162,	127	169,
,000,	168,	202	,016,
,032,	189,	033	017,
,168,	189,	066	,017,
,168	202,	016	241,
,185,	,099,	019	,153,
,200	192,	144,	208,
,000,	185,	179	,019,
,177	200,	192	168,
,160	,000,	185	,091,
,000	178,	200	,192,
,245	,169,	160	,141,
,169	000	141	,000,
,185	,000,	164	,024,
,153	,001,	164	,185,
,105	,000	,153	,033,
,192	_r025	208	,234,
,141	,175,	002	,141,
,141	,177,	002	,169,
,168	,002	,169	,001,
,120	,169	127	,141,
,169	_r001	,141	,026,
,000	,141	018	,208,
,208	_r041	,127	,141,
,173	,020	,003	,141,
,173	_r021	003	,141,
,169	_r072	,141	,020,
,016	,141	,021	,003,
,000	,141	172	,002,
,002	,141	,174	,002,
,141	,183	002	,173,
,141	,167	,002	,169,
,033	_r208	169	,160,
,002	_r169	,147	,032,
,169	,004	,141	,136,
,006	,141	,033	,208,


	040,	064
	000,	251
	254,	218
	000,	148
	208,	019
	208,	017
	141,	149
	017,	065
	208,	179
	169,	017
	000,	114
	141,	004
	000,	006
	250,	104
	157,	163
	157,	191
	160,	195
	000,	047
	245,	250
	153,	043
	208,	042
	020,	060
	208,	040
	032,	070
	164,	015
	105,	029
	032,	220
	164,	014
	169,	173
	176,	042
	255,	159
	133,	033
	013,	028
	208	,196
	173,	,146
	017	250
	123	,117
	124	,189
	003	,138
	088	,161
	141	,098
	169	,140
	168	,156
	001	229
	141	,093
	210	,199
	002	,216
	160	,232

155



	6	Machine Language Games

	2337 :023,185,105,021,153,154,162 2343 :163,136,016,247,169,081,083 2349 :141,187,163,160,002,162,092 2355 .-000,185,175,002,032,202,135 2361 :015,157,179,163,165,021,245 2367 .-157,180,163, 232, 232,136,139 2373 :016,237,169,001,133,027,140 2379 :238,167,002,173,167,002,056 2385 :201,043,144,005,169,039,170 2391 :141,167,002,160,063,169,021 2397 :255,153,064,164,136,016,113 2403 :250,172,167,002,185,215,066 2409 :021,072,141,180,002,185,194 2415 :172,021,072,024,109,180,177 2421 :002,141,180,002,185,129,244 2427 :021,170,024,109,180,002,117 2433 :141,180,002,160,000,224,068 2439 1000,240,009,169,001,153,195 2445 :064,164,200,202,208,247,202 2451 :104,170,240,009,169,002,073 2457 :153,064,164,200,202,208,120 2463 :249,104,170,240,009,169,076 2469 1003,153,064,164,200,202,183 247 5 .-208,249,160,06 3,03 2,148,007 2481 :015,041,031,056,233,010,051 2487 :048,246,201,002,144,242,042 2493 :153,192,164,032,148,015,125 2499 :153,128,164,136,016,230,254 2505 .-169,130,133,025,032,006,184 2511 :017,173,183,002,032,202,048 2517 :015,141,188,163,165,021,138 2523 :141,189,163,169,049,141,047 2529 :001,208,169,141,141,024,141 2535 :208,169,003,141,039,208,231 2541 :169,011,141,032,208,169,199 2547 :000,141,028,208,169,160,181 2553 .-141,248,163,169,001,141,088 2559 -.021,208,169,000,141,182,208 2565 :002,133,032,173,031,208,072 2571 :165,027,208,010,165,033,107 257 7 :240,003,032,241,010,076,107 2583 :006,011,173,178,002,141,022 2589 :179,002,032,237,013,169,149 2595 :000,133,027,160,018,169,030 2601 :001,153,153,217,152,024,229 2607 :105,128,153,154,161,162,142 2613 :007,185,043,021,032,221,050 2619 :010,202,016,247,136,016,174 2625 -.2 30,162,000,032,131,016,124

	156



	Machine Language Games

	2631 -.224,051,208, 111, 162,000,059 2637 :160,018,185,062,021,032,043 2643 :221,010,136,016,247,173,118 2649 :000,220,201,111,240,091,184 2655 :142,169,002,162,100,032,190 2661 :245,015,174,169,002,232,170 2667 2 224,008,144,222,173,167,021 2673 :002,024,105,001,032,179,200 2679 :015,032,202,015,141,243,255 2685 :161,165,021,141,244,161,250 2691 :173,000,220,201,111,240,052 2697 :048,201,126,208,017,238,207 2703 :167,002,173,167,002,201,087 2709 :030,144,026,169,000,141,147 2715 .-167,002,240,019,201,125,141 2721 :208,224,206,167,002,173,117 2727 :167,002,201,255,208,005,237 2733 :169,029,141,167,002,162,075 2739 :060,032,245,015,076,111,206 2745 :010,160,018,169,032,153,215 2751 :154,161,136,016,250,141,025 2757 .-243,161,141,244,161,173,040 2763 :000,220,201,127,208,249,184 2769 :206,167,002,173,167,002,158 2775 :141,168,002,076,075,009,174 2781 .-010,010,010,141,235, 010,125 2787 :152,010,010,010,141,238,020 2793 :010,189,000,178,157,000,255 2799 :180,096,169,000,141,005,062 2805 2 212,169,240,141,006,212,201 2811 2 169,001,141,001,212,169,176 2817 2 033,141,004,212,096,173,148 2823 2 000,220,073,127,133,036,084 2829 2 169,000,133,031,165,036,035 2835 2 041,001,240,010,173,001,229 2841 -.208,201,059,144,019,206,094 2847 2 001,208,165,036,041,002,228 2853 2 240,010,173,001,208,201,102 2859 2 214,176,003,238,001,208,115 2865 2 165,036,041,004,240,034,057 2871 2 169,001,133,031,169,161,207 2877 2 141,248,163,173,178,002,198 2883 2 041,007,201,007,240,006,057 2889 2 238,178,002,076,127,011,193 2895 2 169,000,141,179,002,198,000 2901 2 025,032,063,014,165,036,164 2907 .-041,008,240,032,169,001,070 2913 2 133,031,169,160,141,248,211 2919 2 163,173,178,002,041,007,155

Machine Language Games


2925	:240	,006	_r206	_r178	_r002	,076	,049
2931	:127	,011	_r169	_r007	rl41	,179	,237
2937	:002	_r230	_r025	,032	_r063	,014	,231
2943	:173	,178	_r002	,141	,179	,002	,034
2949	:165	_r031	,208	,007	,169	,000	,201
2955	:141	_f000	_r212	,240	_r005	,169	,138
2961	:064	,141	_r000	,212	,238	,182	,214
2967	:002	_r169	,012	,056	,237	,167	,026
2973	:002	,048	,004	,201	,007	,176	,083
2979	:002	_r169	,007	,205	,182	,002	,218
2985	:240	_r012	,165	,031	,208	,016	,073
2991	:162	_r001	,032	,245	,015	,076	,194
2997	:191	,011	,032	,056	,014	,169	,142
3003	:000	,141	,182	,002	,173	,031	,204
3009	:208	,208	003	,076	,129	,012	,061
3015	:032	,006,	,017,	,169	,141	,141	,193
3021	:019	,212,	169,	000,	,141	,020	,254
3027	:212	,141,	014,	212,	,169	,070	,005
3033	:141	015,	212,	169	008,	,141	,135
3039	:018	,212,	169,	129,	,141,	,018	,142
3045	.-212,	173,	183,	002,	072,	,248	,095
3051	:056,	,233,	001,	216,	141,	,183,	,041
3057	:002,	169,	002,	141,	039,	,208	,034
3063	:169,	000,	133,	029,	,133,	,028	,227
3069	:133,	030,	141,	032,	208,	165,	,194
3075	:029,	024,	105,	006,	133,	029,	,073
3081	:144,	002,	230,	030,	165,	028	096
3087	:024,	101,	029,	133,	028,	,008	,082
3093	:173,	001,	208,	101,	030,	,141	,163
3099	:001,	208,	176,	027,	040,	176	,143
3105	:004,	165,	030,	240,	008,	173	,141
3111	:032,	208,	073,	002,	141,	032	,015
3117	1208,	173,	178,	002,	141,	179,	158
3123	:002,	032,	056,	014,	076,	002,	233
3129	.-012,	104,	169,	003,	141,	039,	013
3135	1208,	169,	011,	141,	032,	208,	064
3141	:162,	255,	032,	245,	015,	104,	114
3147	:240,	003,	076,	205,	009,	162,	002
3153	:104,	032,	131,	016,	160,	002,	014
3159	:185,	172,	002,	217,	175,	002,	072
3165	:144,	016,	208,	003,	136,	016,	104
3171	:243,	160,	002,	185,	172,	002,	095
3177	:153,	175,	002,	136,	016,	247,	066
3183	:169,	000,	141,	024,	212,	162,	051
3189	:255,	032,	245,	015,	169,	015,	080
3195	:141,	024,	212,	076,	241,	008,	057
3201	:165,	032,	240,	002,	198,	032,	030
3207	:165,	036,	041,	016,	208,	007,	096
3213	:169,	080,	133,	032,	076,	138,	001

158



	Machine Language Games

	3219 :013,165,032,201,079,240,10s 3225 :008,201,000,208,243,169,214 3231 :030,133,032,169,009,141,161 3237 :012,212,169,000,141,013,200 3243 :212,141,007,212,169,030,174 3249 :141,008,212,169,129,141,209 3255 :011,212,160,018,173,248,237 3261 .-163,056,233,160,141,170,088 3267 :002,208,002,160,021,162,238 3273 :007,169,000,157,080,176,022 3279 :202,016,250,173,001,208,033 3285 :056,233,002,141,169,002,048 3291 -.041,007,170,169,085,157,080 3297 :080,176,173,169,002,074,131 3303 :074,074,056,233,005,141,046 3309 :169,002,170,032,131,015,244 3315 :177,251,201,043,144,004,039 3321 :201,046,144,046,201,052,171 3327 :176,012,201,046,176,032,130 3333 .-201,007,144,004,201,010,060 3339 -.144,024,169,010,145,251,242 3345 .-169,001,145,253,192,000,009 3351 :240,012,136,173,170,002,244 3357 .-208,212,200,200,192,040,057 3363 -.144,206,140,171,002,076,006 3369 :089,013,140,171,002,162,106 3375 :063,189,192,164,205,169,005 3381 :002,240,006,202,016,245,252 3387 :076,089,013,173,171,002,071 3393 .-024,101,025,221,128,164,216 3399 -.208,239,189,064,164,201,112 3405 :004,176,232,142,181,002,046 3411 :206,180,002,032,004,016,011 3417 :162,005,032,245,015,169,205 3423 -.032,172,171,002,192,020,172 3429 :240,013,145,251,136,174,036 3435 :170,002,240,244,200,200,139 3441 :076,099,013,162,001,032,240 3447 :245,015,173,031,208,169,192 3453 :000,141,011,212,173,178,072 3459 :002,141,179,002,032,063,038 3465 :014,165,197,201,004,208,158 3471 -.003,076,085,012,201,005,013 3477 .-208,020,165,03 3,073,001,137 3483 :133,033,240,005,032,241,071 3489 .-010, 208,061,169,008,141, 246 3495 :004,212,208,054,201,003,081 3501 :240,004,201,063,208,050,171 3507 :173,141,002,240,015,169,151

Machine Language Games

3513 3519 3525 3531 3537 3543 3549 3555 3561 3567 3573 3579 3585 3591 3597 3603 3609 3615 3621 3627 3633 3639 3645 3651 3657 3663 3669 3675 3681 3687 3693 3699 3705 3711 3717 3723 3729 3735 3741 3747 3753 3759 3765 3771 3777 3783 3789 3795 3801


071	,141	,024	,003,	,169,
141	_r025	,003	,169	000,
198	,000	,036	,197	,080,
169	,000	,141	,024,	,212,
000	,220	,201	,111	240,
165	,197	,201	,063	,240,
201	,003	,208	,239,	036,
080	,252	,169	,015	,141,
212	,076	,006	011	,165,
141	,169,	,002	,165,	,025,
170,	002,	,160	,000	173,
002,	,240	,005	,044	,017,
016,	,251,	,173,	,179	002,
178,	,002	174	,169	002,
099,	017,	170	032,	131,
169,	,032,	,145,	251,	,174,
002,	189,	099,	018,	072,
099,	017,	170	,032,	131,
169,	013,	145,	253,	,104,
251,	238,	169,	,002,	238,
002,	200,	192	040,	208,
096,	169,	,000,	,141,	,171,
240,	005,	169,	001,	141,
002,	032,	237	,013	,162,
142,	169,	002,	,174,	169,
189,	064,	164,	201,	016,
071,	201,	057,	144,	,058,
015,	173,	180,	,002,	,208,
236,	181,	002,	208,	038,
003,	141,	039	208,	169,
141,	032,	,208,	,248,	,173,
002,	024,	105	,001.	,141,
002,	216,	165	,025,	133,
162,	052,	,032,	,131,	,016,
011,	141,	032,	208,	076,
009,	072,	104,	136,	208,
076,	113,	015,	074,	074,
024,	105,	003,	254,	064,
141,	184,	002,	188,	128,
140,	185,	002,	188,	192,
140,	186,	002,	172,	171,
208	105,	,201,	,003,	240,
201,	,002,	,240,	032,	176,
032	,173	,015	,240	,003,
255	,014	,032	,173	,015,
082	,032	,173	,015	,240,
206	,185	,002	,206	,185,
238	_r185	,002	_r076	,026,
238	_r185	,002	,032	rl48,


	254	,079
	133	,150
	252	,192
	173	,154
	014	,227
	004	,061
	197	,081
	024	,140
	026	,217
	141	,114
	171	153
	208	,255
	141	,251
	189	,209
	015,	,221
	170,	,192
	189,	082
	015,	239
	145,	,098
	170,	087
	210,	133
	002	,122
	171,	020
	000,	001
	002,	219
	144,	089
	160,	008
	043,	,200
	169,	163
	012	,163
	183,	070
	183,	059
	026	,176
	169	,177
	075,	164
	251,	151
	074,	059
	164,	253
	164,	196
	164,	010
	002,	074
	055	219
	095,	159
	032	,170
	240	,154
	006	,235
	002	,223
	015	,241
	015	_r069

160

Machine Language Games


041	,007	,208	,055,
014	,206,	185	002,
015	,206,	rl85,	,002,
015	_r041	007	,208,
255	,014,	,238	,185,
026	r015,	,032	,173,
011	_r173	,186,	,002,
240	_r014	,206	,186,
173	,186	,002	,201,
003	_r238,	186	,002,
128	_r164	,056	,229,
040	_r176	017	,168,
164	,170	,032	,131,
032	,145	,251	,136,
145	,251	,173	,185,
229	,025,	,201	,040,
168	,174	,186	,002,
015	,174,	,184	,002,
021	rl45	,253	,138,
042	,145,	,251	,136,
189	,080	,021	,145,
024	rl05,	,032	,145,
169	,002,	173	,185,
128	,164,	,173,	,186,
192	_r164	,238	,169,
169,	_r002,	201,	,064,
076	,076,	,014	,165,
026,	r096,	189,	000,
251,	,133,	253,	189,
133,	252,	073,	120,
096,	056,	165,	140,
101,	144,	133,	139,
162,	004,	181,	139,
202,	016,	249,	104,
139,	,096,	032,	148,
001,	096,	162,	000,
162,	008,	248,	010,
020,	101,	020,	133,
202,	208,	244,	165,
096,	072,	041,	015,
071,	133,	021,	104,
074,	074,	024,	105,
020,	096,	160,	002,
185,	172,	002,	032,
157,	160,	163,	165,
161,	163,	232,	232,
237,	096,	152,	072,
072,	104,	136,	208,
208,	248,	104,	168,


032	,255	,053
076	,026	,226
032,	,148	,055
036	,032	,068
002	,076	,249
015	,240	,242
201	,002	,066
002	,096	,241
021	,240	,070
096	,189	,223
026	,201	,063
189	192	,047
015	,169	,208
048	,002	,147
002	,056	,095
176,	035	_r251
032	,131	,244
189,	,089	,210
024	,105	,249
048,	,011	,202
253	,138	,145
251	,174,	,056
002	157	,019
002	,157,	,147
002	,173	,025
240,	003,	,028
025,	133,	,100
164,	133	225
032,	164,	133
133,	254,	082
101,	143,	080
138,	072,	112
149,	140,	,166
170,	165,	047
015,	041,	130
134,	020,	078
072,	165,	080
020,	104,	075
020,	216,	226
024,	105,	042
074,	074,	172
071,	133,	182
162,	000,	147
202,	015,	065
021,	157,	030
136,	016,	153
160,	255,	191
251,	202,	198
096,	188,	243

161



	v*fc Machine Language Games

	4101 :064,164,185,098,021,248,017 4107 -.024,109,172,002,141,172,119 4113 .-002,173,173,002,105,000,216 4119 -.141,173,002,173,174,002,176 4125 .-105,000,141,174,002,216,155 4131 :169,016,157,064,164,032,125 4137 :221,015,169,138,141,019,232 4143 :212,169,000,141,020,212,033 4149 :141,014,212,169,060,141,022 4155 -.015,212,169,008,141,018,110 4161 :212,169,129,141,018,212,178 4167 :096,173,025,208,141,025,227 4173 :208,041,001,240,043,162,004 4179 :233,173,178,002,009,016,182 4185 :168,173,018,208,016,004,164 4191 :162,006,160,000,142,018,071 4197 :208,173,017,208,041,127,107 4203 .-141,017,208,140,022,208,075 4209 :173,013,220,041,001,240,033 4215 :005,198,002,076,049,234,171 4221 :104,168,104,170,104,064,071 4227 :032,006,017,232,189,002,097 423 3 :022,141,169,002,202,160,065 4239 :000,189,002,022,153,003,000 4245 :212,153,010,212,153,017,138 4251 :212,232,200,192,004,208,179 4257 :238,169,002,141,170,002,115 4263 :169,212,133,021,032,016,238 4269 :017,172,170,002,185,102,053 4275 :021,133,020,160,000,189,190 4281 :002,022,145,020,232,200,038 4287 :192,002,208,245,189,002,005 4293 :022,240,062,2 32,142,171,042 4299 :002,170,160,004,169,008,204 4305 1145,020,173,169,002,145,095 4311 :020,134,002,172,000,220,251 4317 :192,111,208,011,032,006,013 4323 :017,172,000,220,192,111,171 4329 :240,249,096,166,002,208,170 4335 :234,041,2 54,160,004,145,053 4341 :020,172,170,002,136,016,249 4347 :002,160,002,140,170,002,215 4353 :174,171,002,208,168,160,116 4359 :023,169,000,153,000,212,052 4365 :136,016,250,169,008,141,221 4371 :004,212,141,011,212,141,228 4377 .-018,212,169,015,141,024,092 4383 :212,096,248,000,000,160,235 4389 .-031,252,144,001,000,136,089

	162

Machine Language Games

4395 4401 4407 4413 4419 4425 4431 4437 4443 4449 4455 4461 4467 4473 4479 4485 4491 4497 4503 4509 4515 4521 4527 4533 4539 4545 4551 4557 4563 4569 4575 4581 4587 4593 4599 4605 4611 4617 4623 4629 4635 4641 4647 4653 4659 4665 4671 4677 4683


002	,124,	135,	255	,249	128,
000	005,	127	000	,007,	017,
240	_r 133,	000	,015	,249	,000,
002,	032,	000,	001	192	000,
000,	,031,	063	,248	,005	000,
128	009,	062,	064	,017	159,
255	,225,	160	,000	001	,224,
000	254,	161,	015	136	159,
240	_r000,	004,	064,	000,	003,
128,	000,	022,	022,	022	022,
022	,022,	022	,022	022	022,
022	,022,	022,	022	,022	,022,
022	,022,	022	022	,022	022,
022,	022,	022	022,	022	022,
022	022,	022	022	,022,	022,
022,	022,	022,	022	022,	022,
022	,021,	021	020	019	018,
017,	016,	015,	014,	,014	015,
016	017,	018,	019,	019,	020,
020,	019,	018,	017,	017,	016,
016,	,016,	017,	,017	017	017,
017,	018,	019,	020,	021	021,
021,	020,	020,	020,	019,	019,
018,	018,	018,	018,	019,	019,
020,	021,	021,	021,	,021,	021,
021,	021,	021,	021,	021,	021,
021,	021,	021,	020,	020,	019,
018,	017,	016,	016,	015,	015,
015,	016,	016,	016,	016,	017,
017,	017,	017,	017,	017,	017,
017,	016,	016,	016,	016,	017,
018	,018	,017	,017	,016	,016,
015	_r015	,014	,013	,013	,012,
011	,010	,009	,008	,007	,007,
006	_r006	,006	,006	,007	,008,
009	,010	,011	,012	,013	,014,
015	,016	,017	,018	,019	,020,
021	,022	,022	,022	,022	,022,
022	,022	,021	,021	,020	,020,
020	,020	,020	,019	,018	,017,
016	,016	,015	,014	,014	,013,
013	,013	,013	,013	,014	,014,
015	,015	,016	,016	,017	,018,
018	,019	,019	,020	,020	,021,
021	_r021	,021	,021	,021	,021,
020	,020	,019	,019	,018	,018,
017	,017	,016	,016	,015	,015,
014	,014	,013	,013	,013	,013,
013	,014	,014	,015	,015	,016,

,168 ,205 ,180 ,032 ,158 ,000 ,176 ,042 ,146 ,057 ,235 ,241 ,247 ,253 ,003 ,009 ,004 ,236 ,004 ,008 ,007 ,029 ,038 ,035 ,056 ,063 ,065 ,046 ,051 ,063 ,065 ,075 ,061 ,037 ,030 ,066 ,108 ,140 ,141 ,135 ,115 ,113 ,136 ,162 ,177 .171 ,159 ,149 ,162

163

Machine Language Games


4689	1017,018	,019	_r019,020	,020	,194
4695	:020,020	_r020	_r021,021	,021	,210
4701	*:020_t020*	,020	,021,021	,022	,217
4707	*1000,000*	_r000	*,000,000*	,000	,099
4713	*1000,000*	,000	,000,000	,000	,105
4719	*z000,000*	_r000	,000,000	,000	rill
4725	:000,000	,000	,000,000	,000	,117
4731	:000,000	,000	,000,000	,000	,123
4737	:000,000	,000	,000,000	,000	,129
4743	:000,000	, 000	,000,000	,003	,138
4749	:004,001	,001	,001,001	,001	,150
4755	:001,001	,002	,002,002	,002	,157
4761	:002,005	,006,	,000,000	,001,	,167
4767	:001,003	,004	,001,000	,002,	,170
4773	:005,006,	,007,	,008,009	,002,	,202
4779	:002,002,	,000,	,000,000	,003	,178
4785	:004,000,	003,	004,001	,000,	,189
4791	:000,002	,005,	,006,002	,000,	198
4797	:000,000,	000,	000,000,	,000,	189
4803	:000,000,	000,	,000,000,	,000,	195
4809	:000,003,	004,	,001,001,	,001,	211
4815	:001,000,	,007	,008,009,	,000	232
4821	:000,005,	_r006	,000,000	,000,	,224
4827	:000,000,	,000	,000,000	,003,	222
4833	: 004,000,	002,	,002,000,	,000,	233
4839	:003,004,	003,	,004,003	,004,	,252
4845	:001,003,	004,	,001,001,	,001,	,248
4851	:001,001,	003,	004,003,	,004,	,003
4857	:000,002,	002,	,002,002,	,002,	003
4863	:002,002,	002,	,002,002,	,002,	011
4869	:002,002,	002,	002,002,	000,	,015
4875	:000,000,	000,	000,000,	,000,	,011
4881	:003,004,	007,	008,009,	003,	051
4887	:004,001,	001,	,001,003	004,	,037
4893	:001,003,	004,	003,004,	,000,	044
4899	:005,006,	005,	006,005,	,006,	,068
4905	:005,006,	002,	005,006,	,005,	,070
4911	:006,005,	006,	000,000,	,000,	,064
4917	:000,000,	000.	000,003,	004,	060
4923	:003,004,	003,	004,003,	004,	080
4929	-.003,004,	003,	004,003,	004,	086
4935	:003,004,	000,	005,006,	005,	094
4941	:006,005,	006,	002,002,	002,	100
4947	:005,006,	000,	000,000,	,005,	099
4953	:006,000,	000,	000,007,	,008,	,110
4959	:009,005,	006,	,000,085	,000,	,200
4965	:000,000,	,000,	,000,000	,000	,101
4971	:001,001,	,004	,004,016	,016	,149
4977	:064,064,	,064	,064,016	,016	,145

164



	Machine Language Games

	4983 :004,004,001,001,000,000,129 4989 :000,000,001, 004,016,064,210 4995 :001,004,016,064,000,000,216 5001 :000,000,064,016,004,001,222 5007 :000,000,000,000,000,000,143 5013 :000,000,064,016,004,001,234 5019 1005,005,024,024,106,038,101 5025 :038,070,000,000,067,067,147 5031 :147,128,128,149,000,192,143 5037 :240,240,240,128,128,149,018 5043 :000,000,000,000,000,000,179 5049 :000,000,003,015,015,015,233 5055 :003,001,002,002,194,192,073 5061 :240,058,042,010,002,000,037 5067 :063,008,032,255,249,246,032 5073 :063,008,000,000,001,003,028 5079 :003,001,000,000,000,003,222 5085 -.007,015,015,007,003,000,012 5091 :003,015,062,058,058,062,229 5097 :015,003,000,003,006,012,016 5103 :012,006,003,000,000,000,004 5109 :001,002,002,001,000,000,251 5115 :000,000,000,001,001/000,253 5121 :000,000,000,000,000,000,001 5127 :000,000,000,000,192,240,183 5133 :240,240,192,064,128,128,237 5139 :168,048,012,170,218,122,245 5145 :168,048,194,002,010,248,183 5151 :252,240,192,000,000,000,203 5157 :128,192,192,128,000,000,165 5163 :000,192,224,240,240,224,139 5169 :192,000,192,240,188,172,009 5175 :172,188,240,192,000,192,015 5181 :096,048,048,096,192,000,029 5187 :000,000,128,064,064,128,195 5193 :000,000,000,000,000,128,201 5199 :128,000,000,000,000,000,207 5205 :000,000,000,000,000,000,085 5211 :238,238,238,254,254,238,015 5217 :238,238,254,254,056,056,169 5223 :056,056,254,254,124,254,077 5229 :224,238,238,238,254,124,145 5235 -.126,254,224,252,126,014,087 5241 :254,252,124,254,238,224,187 5247 :224,238,254,124,252,254,193 5253 :238,254,252,238,238,238,055 5259 :254,254,224,252,252,224,063 5265 2 254,254,124,254,238,238,227 5271 :238,238,254,124,056,120,157

Machine Language Games


5277	:248,	056
5283	:252,	254
5289	1254,	254
5295	2124,	014
5301	1126,	238
5307	2254,	254
5313	2254,	124
5319	2254,	238
5325	-.014,	028
5331	2124,	254
5337	2254,	124
5343	2126,	014
5349	2114,	038
5355	2254,	254
5361	2056,	056
5367	2252,	224
5373	2254,	254
5379	1028,	056
5385	2000,	000
5391	2238,	238
5397	2238,	254
5403	2252,	254
5409	2254,	252
5415	2 000,	000
5421	2 004,	000
5427	2020,	021
5433	2022,	006
5439	2005,	006
5445	2001,	005
5451	2025,	024
5457	2009,	015
5463	2 003,	004
5469	2001,	001
5475	2 080,	117
5481	2067,	068
5487	2071,	071
5493	2032,	032
5499	:032,	,067
5505	2 004,	008
5511	2008,	,012
5517	2012,	008
5523	2016,	,020
5529	2016,	,014
5535	2020,	,016
5541	2022	,030
5547	2 064	,003
5553	2010	,008
5559	2010	,014
5565	2012	,016

,056,056

,014,028

,252,254

,254,252

254,254

,224,252

124,252

254,124

056,056

238,124

124,254

126,124

254,240

056,056

254,254

224,224

254,254

112,000

238,238

124,056

252,224

,238,254

000,000

018,007

003,025

020,002

,003,003

006,025

,006,002

,011,001

,002,009

,009,003

,117,000

,071,069

,071,071

,064,065

,068,071

,010,012

,012,012

,018,014

,020,020

,020,016

,017,017

,004,004

,008,006

,010,012

,010,018


	,254,	254,
	,112,	224,
	,014,	124,
	,014,	030,
	,014,	014,
	,254,	014,
	,224,	252,
	,254,	254,
	,056,	056,
	,254,	238,
	,238,	254,
	,000,	000,
	,000,	000,
	,056,	056,
	,224,	252,
	,206,	238,
	,238,	230,
	,000,	000,
	,238,	238,
	,252,	254,
	,224,	224,
	,252,	238,
	,000,	000,
	,005,	001,
	,019,	006,
	,005,	006,
	,006,	023,
	,025,	019,
	,018,	007,
	,001.	,020,
	,001,	009,
	,011,	,011,
	,004,	,002,
	,007	,014,
	,070	032,
	,071,	,071,
	,066,	,064,
	,069	,070,
	,012,	,012,
	,008	,012,
	,008,	,016,
	,020	,020,
	,014	,020,
	,016	,024,
	,000	,000,
	,002	,006,
	,010	,004,
	,006	r010,
	,016	,012,

166

Machine Language Games


	5571	:014
	5577	:018
	5583	:020
	5589	:064
	5595	:006
	5601	:016
	5607	:018
	5613	:012
	5619	:024
	5625	:018
	5631	:064
	5637	:201
	5643	:015
	5649	:015
	5655	:060
	5661	:015
	5667	:015
	5673	:030
	5679	:015
	5685	:000
	5691	:018
	5697	:018
	5703	:018
	5709	:015
	5715	:018
	5721	:031
	5727	:025
	5733	:018
	5739	:065
	5745	:071
	5751	:071
	5757	:143
	5763	:097
	5769	:071
	5775	:143
	5781	:097
	5787	:097
	5793	:143
	5799	:097
	5805	:071
	5811	:097
	5817	:000

,016,020 ,014,020 ,016,017 ,000,003 ,002,008 ,010,006 ,012,008 ,014,016 ,018,022 ,020,026 ,000,000 ,031,021 ,024,014 ,143,010 ,031,021 ,024,014 ,143,010 ,031,021 ,024,014 ,000,033 ,015,000 ,010,031 ,010,195 ,011,195 ,021,165 ,023,049 ,042,041 ,044,000 ,128,249 ,006,010 ,006,020 ,010,060 ,008,010 ,006,020 ,010,030 ,008,010 ,008,020 ,012,060 ,008,010 ,006,020 ,008,060 ,000,000


	,016,	,024,
	,020,	022,
	,017,	030,
	,004,	006,
	,008,	010,
	,014,	012,
	,010.	,008,
	,014,	,016,
	,020,	,020,
	,017,	030,
	,000,	,033,
	,015,	rl43,
	,060,	,031,
	,015,	,024,
	,015,	,143,
	,030,	031,
	,015	,024,
	,015,	143,
	,060,	000,
	,076,	,201,
	,000,	,005,
	,021,	010,
	,016,	,010,
	,016,	,012,
	,031,	,022,
	,028,	,024,
	,021,	,043,
	,000,	000,
	,071,	,006,
	,097,	008,
	,097	,008,
	,071,	,006,
	,143,	,010,
	,097,	,008,
	,071,	,006,
	,143,	,010,
	,143,	,010,
	,143,	,010,
	,071,	,006,
	,071,	,006,
	,000	,000,
	,000,	,000,


	014,	043
	026,	065
	000,	051
	010,	044
	006,	003
	018,	045
	014,	045
	008,	,061
	022,	113
	017,	121
	076,	172
	010,	170
	021,	176
	014,	238
	010,	047
	021,	164
	014,	,000
	010,	,035
	000,	160
	209,	,060
	209	,050
	209,	108
	210,	,018
	209,	,023
	165,	,249
	030,	018
	209,	,220
	002,	165
	020,	,134
	060,	,109
	010,	,075
	020,	,179
	030	173
	010,	,093
	020,	,167
	060,	221
	010,	,187
	020,	,037
	060,	,163
	010,	,101
	000,	,088
	000,	,185

167



	6 Zuider Zee

	MarcSugiyama

	Your mission is to save your village from flooding. This BASIC and machine language game will provide hours of fun. Requires the use of the MLX program. Your village in Holland is built on land reclaimed from the ocean. High dikes keep the cold waters of the North Sea from flooding your land. But word has come that a terrible storm is approaching. Heavy rains and giant waves will undoubtedly break down sections of the dikes, flooding parts, perhaps all, of your land. But you are prepared. You and your fellow Dutchmen have been battling the sea for centuries. In the old days, bucket brigades and sandbaggers would have fought the storm, and many lives might have been lost. Times have changed. Helicopters will rescue all the people whose homes are flooded, and as for repairing damage to the dikes and pumping out the water, that can aU be done by one person. You. You Are the Dikemaster As dikemaster, you are responsible for repairing the dikes and pumping out the flood waters. You have a truck with the latest landfill equipment, so that all you have to do is back it into place where you want to repair a broken dike. The truck does the rest. You also have four pumps. When a dike has been repaired, you then have to pick up one of the pumps and put it in place on the dike. Then you set it up to pump water from the flooded fields and dump it back into the ocean. But be careful. If you set the pump wrong, it can pump water from the ocean and pour it onto land, making the flood worse than ever. When you have successfully repaired all the dikes and pumped out all the water, you can't relax. You immediately get a promotion, and have to do the same for another village, where the storm is even worse. And if you ever get so far behind that all your land is flooded 168



	Machine Language Games	6

	at the same time—well, you can certainly understand why your fellow villagers will start looking for a new dikemaster. How to Play At the beginning of the game, you will be asked to choose a starting level. Until you get the hang of driving the truck and setting up the pumps, you'd probably better start at level 1, in which the storm is pretty mild and new gaps don't open up so often. Later, though, you can try higher levels. The village. At the beginning of the game, the screen is filled with plowed fields, trees, and houses. The dikes are built, with the dikemaster's depot in the middle. Then the sea covers all the land outside the dikes. Finally, several breaks open in the dikes, and sections of the village lands are flooded. It's time for you to get to work! Scoring. Scoring depends on several factors: how much land is covered with water; what level you are playing at; and how long you can keep the storm from entirely flooding the village. Moving the truck. You drive your truck along the tops of the dikes by using the joystick. The dikes are slightly wider than the truck, so you can maneuver a little from side to side. You can't accidentally drive the truck off the dike. Repairing the dike. Drive the truck to a break in the dike. You will want to dump a load of dirt into the break, to block it. Hold down the joystick button. This puts the truck in reverse. When you move the joystick, the truck will back up, moving the opposite direction from the direction in which you moved the joystick. As long as you keep pressing the button and moving the joystick, the truck will keep backing up. When it reaches the edge of the dike, it stops and dumps a load of dirt off the edge of the dike. This creates a new section of dike. If you steered the truck correctly, the new section will repair the break in the dike. If not, you'll just have an extra load of dirt that doesn't connect with anything. Your truck constantly scoops up more dirt as you drive from place to place—you will never run out of material to repair the dike. Pumping out the water. Once a flooded area is completely surrounded by the dike, with no breaks, you can begin pumping. First, you must go and pick up a pump. At the beginning of the game, all four pumps are just outside the depot. Drive on top of

	169



	f% Machine Language Games the pumps, push the joystick button, and your truck will automatically pick up a pump. Then drive to the edge of the flooded field you want to drain. You will need to place the pump on the dike between the flooded field and the place where you want the water to be dumped. Usually you will want the water to be dumped in the ocean, but sometimes you will dump from one flooded field to another, or even from a flooded field to a field with no water on it. You place the pump by holding down the joystick button and then moving the joystick in the direction where you want the pump to dump the water. Remember, move the joystick in the direction where you want the flood water to end up. You will hear the sound of the pump starting up, and when you drive away, the pump will stay behind. At any time you can go to a pump and pick it up by driving right onto it and pushing the joystick button without moving. You'll always hear the sound of the truck picking up the pump. Then, when you release the button and drive away, the pump will go with you. How pumps work. The pumps are just machines. They aren't very smart. If you set a pump to pick up water from the ocean and dump it onto a field, the pump will do exactly that, and the flooding will get worse instead of better. You'll also come closer to losing your job. However, if you set the pump to draw water from a field that isn't flooded, or set it so that it dumps onto or picks up from the dike instead of a field or the ocean, nothing will happen at all. The joystick button. When you move the joystick without pressing the button, the truck drives around. Pressing down the joystick button can do one of three things: If you do not move the joystick, and the truck is touching a pump but not already carrying one, the truck will pick up that pump and the pump will stop functioning. If you move the joystick when the truck is not carrying a pump, the truck will go into reverse and move the opposite way from the direction you are moving the joystick. As soon as it reaches the edge of the dike, it will dump a load of dirt. If you move the joystick when the truck is carrying a pump, the truck will unload the pump and, if possible, begin dumping water where the joystick movement indicated. Getting promoted. If you ever uncover all the land of your village, you will be promoted and moved to the next village. The 170



	Machine Language Games	6

	game will stop, and the new village will be drawn on the screen. You will be at a harder level of play, which means that breaks will occur more often, and more land will be flooded at the beginning of play. However, you will also get more points at the higher levels. Strategy Tips At lower levels of play, it is possible to repair all the dikes and completely pump out all the water. At higher levels, however, the storm is too intense, and dikes break too often. Here the best strategy is to choose four relatively small enclosures, set a pump on each, and then spend the rest of your time repairing breaks in the dikes as often as possible. The pumps will function whenever the field they are pumping is completely enclosed by dike walls. Since the game ends as soon as all the fields are completely flooded, it's better to keep one area dry, sacrificing the others, than to overextend yourself. You can also take advantage of the fact that your truck will create a dike section wherever you want it. It is possible to build whole new dikes and create new fields. It is also possible to divide a large field into several smaller ones by building new dikes across it. This is particularly helpful at higher levels, when the dike breaks so often that you can't keep a large field completely enclosed long enough for it to be pumped dry. Typing in the Program Most of the program is written in BASIC, but certain key routines are written in machine language and must be entered and SAVEd using the Machine Language Editor (MLX) found at the beginning of this chapter. The MLX is a program that checks your DATA statements as you enter them and prevents you from entering the data incorrectly. Several other games in this chapter and programs in other COMPUTE! books for the Commodore 64 use the MLX program, so if you type it in once and SAVE it, you will use it again and again to enter error-free machine language programs. The first step is to enter and SAVE the machine language routines using MLX. The MLX will ask you for two numbers. Answer the prompts as follows: Starting address: 49152 Ending address: 52040 Then start entering the data using the instructions given with the MLX program. 171



	y% Machine Language Games The next step is to type in and SAVE the BASIC program. The best way to save the two parts of this program is to save the machine language on a tape first and then save the BASIC part immediately after the machine language program. Loading the Program Once you have both parts of the program SAVEd, you are ready to LOAD the program. First LOAD the machine language as follows: From disk: LOAD"fn",8,l From tape: LOAD"", 1,1 where fn is the filename. Type NEW and LOAD the BASIC part as you would any other BASIC program. To begin play, type RUN and the game will begin. Program 1. Zuider Zee: Part 1. BASIC 100 FORI=0TO27:POKE54272+I,0:NEXT:POKE53264,0 110 IFPEEK(49161)<>76THENPRINT"{DOWN}?NO MACHINE L ANGUAGE{2 SPACES}ERROR";:END 120 PRINT"{CLR}{BLK}@@@@@@^M 130 SYS49161:SYS49164:POKE53272,4:POKE648_/128 140 PRINT"{CLR}{GRN}"CHR$(8)CHR$(14):POKE53280,0:P OKE53281,0 150 POKE55,0:POKE56,128:CLR 160 GOSUB1040 170 : 180 REM MAIN LOOP 190 SYS49167.-SYS49170 200 IFPEEK(908)THENPOKE851,1:GOSUB410:POKE851,0 210 IFPEEK(844)=0THEN220 215 PN=PEEK(844)-2:P0KE851,1:GOSUB660:PF(PN)=PF:PO KE844,0:P0KE851,0:GOSUB560 220 IFPEEK(845)=0THEN260 230 PF(PEEK(845)-2)=0:POKE845,0 240 POKEFQ,20:POKEAD,0:POKESR,243:POKECT,17:POKECT ,16 250 GOSUB560 260 IFPEEK(908)=0ANDPEEK(851)=0THEN300 270 FORPN=1TO4:IFPF(PN)=0THEN290 280 GOSUB670:PF(PN)=PF 290 NEXT:POKE851,0:POKE908,0 300 GOSUB870:SYSHM:H1=FND(690):P=Hl/H0 310 IFP>=1THEN2410

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	Machine Language Games	6

	320 IFINT(P100)<3THEN2610 330 GOSUB560:SC=SC+INT(MDP) 340 GETA$:IFA$=""THEN190 350 IFA$="Q"THEN2620 360 IFA$o^u{Fl}^MTHEN190 370 POKE53280,14:POKE834,0:POKE198,0:WAIT198,1:POK E198,0:POKE834,1:POKE53280,6 380 GOTO190 390 : 400 REM FLOOD 410 FS=FND(900):IS=FND(902) 420 X=PEEK(680):Y=PEEK(681) 430 IT=PEEK(907):FI=PEEK(906):FL=PEEK(909)-33:TL=P EEK(910)-33 440 IFFL<0ORTL>14ORFL>14THENRETURN 450 IFTL<0THENTL=0 460 POKEX+Y40+S,11:IFFIANDITTHENLV=40:GOTO510 470 IFTL=FLTHENLV=TL:GOTO510 480 IFFIORITTHENLV=7:GOTO510 490 POKEFQ,8:POKEAD,0:POKESR,122:POKECT,129 500 LV=(TLIS+FLFS)/(IS+FS) 510 IFLV=0THENLV=7 520 SYSFM,X,Y,31,14:SYSFM,X,Y,LV+33,14:POKECT,128 530 RETURN 540 : 550 REM STATUS LINE 560 POKE214,23:PRINT:PC=-(P>.25)-(P>.50)-(P>.75)~( P>1)+1 570 PRINT" {RVSHYEL} RANK: "MID$ ( STR$ ( SK) , 2 ) " SCORE • 7* 580 PRINTTAB(l4)RIGHT$("000000"+MID$(STR$(lNT(SC/l 0)10)_#2)_/6); 590 PRINT" ST:"MID$("{RED}{CYN){YEL}{GRN}{WHT}"_/PC ,1)" {YEL}"; 600 PRINT" PUMPS:";:F0RI=1T04:PRINTTAB(12+30)• 610 IFPF(I)THENPRINTMID?("{RED}{CYN}{PUR}{GRN}"_fI, 1)MID$(STR$(I),2);:GOTO630 620 PRINT"{YEL} 630 NEXT:PRINT"{HOME}":RETURN 640 : 650 REM START/CHECK PUMP 660 XP(PN)=PEEK(848):YP(PN)=PEEK(849):DP(PN)=PEEK( 850) 670 PF=0:X=XP(PN):Y=YP(PN):D=DP(PN) 680 FP(PN)=X+40Y+S-D(D):TP(PN)=X+40Y+S+D(D) 690 FC=PEEK(FP(PN)):IFFC=11ORFC=32ORFC=31THENFC=40 700 FC=FC-33:IFFC<0ORFO14THENRETURN 710 TC=PEEK(TP(PN)):IFTC=11ORTC=32ORTC=31THENTC=40 720 TC=TC-33:IFTC<0THENTC=0

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	J% Machine Language Games

	730 IFT014THENRETURN 740 NX=X-XD(D):NY=Y-YD(D):SYSFM,NX,NY,11,14 750 SYSFM,NX_/NY,FC+33_/14 760 MF(PN)=0:IFPEEK(905)=0THENMF(PN)=l/FND(690)(8 -SK/2) 770 NX=X+XD(D):NY=Y+YD(D):SYSFM,NX,NY,11,14 780 1FPEEK(FP(PN))=11THENSYSFM,NX,NY,TC+33,14:MF(P N)=0:MT(PN)=0:GOTO810 790 SYSFM,NX,NY,TC+33,14 800 MT(PN)=0:IFPEEK(905)=0THENMT(PN)=l/FND(690)(8 -SK/2) 810 IFPF(PN)THEN840 820 FL(PN)=0:TL(PN)=0 830 POKEFQ,30:POKEAD,0:POKESR,243:POKECT,17:POKECT ,16 840 PF=1:RETURN 850 : 860 REM OPERATE PUMPS 870 FORI=1TO4:IFPF(I)=0THEN1010 880 C1=0:CF=0:FL(I)=FL(I)+MF(I):TL(I)=TL(I)+MT(I) 890 IFFL(I)<1THEN920 900 CF=1:FL(I)=FL(I)-1:FC=PEEK(FP(I))-34:IFFC<0THE NFC=-3 3:PF(I)=0 910 IFFO14THENPF(I)=0:FC=14 920 IFTL(I)<1THEN950 930 Cl=l:TL(I)=TL(I)-1:TC=PEEK(TP(I))-32:IFTO14TH ENTC=14:PF(I)=0 940 IFTC<0THENPF(l)=0:TC=0 950 IFMF(I)=0ORCF=0THEN980 960 XN=XP(I)-XD(DP(I)):YN=YP(I)-YD(DP(I)) 970 POKE851,1:SYSFM,XN,YN,11,12:SYSFM,XN,YN,FC+33, 14+(FC=-33):POKE851,0 980 IFMT(l)=0ORCl=0THEN1010 990 XN=XP(I)+XD(DP(I)):YN=YP(l)+YD(DP(l)) 1000 POKE851,l:SYSFM,XN,YN,11,12:SYSFM,XN,YN,TC+33 ,14:POKE851,0 1010 NEXT:RETURN 1020 : 1030 REM INITIALIZE 1040 PRINT"{CLR}"; 1050 JY=56320:IFPEEK(1024)=0THENGOSUB2090 1060 I=RND(-RND(0)) 1070 DIM X0(7),X1(7),Y0(7),Y1(7),XP(4),YP(4),DP(4) 1080 DIM PF(4),FL(4),TL(4),FP(4),TP(4),MT(4),MF(4) 1090 S=32768:C=22528:FM=49152:BX=49155:HM=49158 1100 FQ=54280:AD=54284:SR=54285:CT=54283 1110 DEFFNR(X)=INT(RND(1)X) 1120 DEFFND(X)=PEEK(X)+256PEEK(X+l) 1130 REM SPRITE DATA

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	Machine Language Games	6

	1140 IFPEEK(1024)THENFORI=1TO605:READA:NEXT:GOTO12 20 1150 POKE1024,1:FORI=0TO25:SQ=34816+I64:J=0 1160 READA:IFA<0THENSQ=SQ-A:J=J-A:GOTO1180 1170 P0KESQ,A:SQ=SQ+1:J=J+1 1180 IFJ<63THEN1160 1190 NEXT 1200 PRINTSPC(5)" PRESS THE TRIGGER TO CONTINUE {UP}^M:GOSUB2750 1210 GOSUB1990 1220 POKE53272,8 1230 REM CHAR DATA 1240 PRINT"{CLR}{GRN}":F0RI=1T012:READB:FORJ=0TO7: READA 1250 POKE40960+B8+J,A:NEXT:NEXT 1260 FORI=0TO3:READXD(I),YD(I):NEXT:FORI=0TO3:READ D(I):NEXT 1270 POKE53280,6:POKE53281_/0:SK=PEEK(1026):GOSUB13 60 1280 POKE53269,251 1290 A=0:FORI=53254TO53260STEP2:POKEI,162+A:POKEI+ 1,132:A=A+2:NEXT 1300 A=2:FORI=53290TO53293:POKEI,A:A=A+1:NEXT:FORI =3 3786TO33 790:POKEI,46:NEXT 1310 TT=0:MD=3+SK2:MR=26+52(SK-l) 1320 SC=FND(1027)10 1330 POKE904,MD:POKE912,MR:POKE834,1:RETURN 1340 : 1350 REM MAKE ISLAND 1360 POKE214_/23:PRINT:PRINT^,,{RVS} {YEL} {39 SPACES} {HOME}"; 1370 POKE33767,160:POKE56295,7 1380 GOSUB560 1390 SYSFM,RND(1)40_/RND(1)25,0,13 1400 SYSBX,18,9,21,12,64,14:SYSFM,19,10,1,9:POKES, 0:POKES+C,13 1410 POKE419+S,1:POKE420+S,2:POKE459+S,64:POKE459+ S+C13 1420 POKE460+S,3:POKE460+S+C,13 1430 REM DAMS 1440 FORI=0TO7 1450 X0=FNR(10)3:X1=X0+(FNR(10)+1)3:IFX0=0ORX1>3 8THEN1450 1460 Y0=FNR(7)3:Y1=Y0+(FNR(7)+1)*3:IFY0=0ORY1> 23T HEN1460 1470 SYSBX,X0,Y0,XI,Yl,64,14:X0(I)=X0:Y0(I)=Y0:X1( I)=X1:Yl(I)=Y1:NEXT 1480 SYSFM,0,0,5,13 1490 REM TREES/HOUSES

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	f\ Machine Language Games

	1500 FORI=1TO30 1510 X=FNR(37)+1:Y=FNR(22)+1:T=X+Y40+S 1520 IFPEEK(T)=0ORPEEK(T)=5THENPOKET,3 1530 NEXT 1540 FORI=0TO9 1550 X=FNR(37)+1:Y=FNR(22)+1:T=X+Y40+S 1560 IFPEEK(T)THEN1550 1570 P0KET,4:P0KET+C, 11: POKE52320+I ,X: POKE52352+I, Y:NEXT 1580 REM WATER/AMOUNT LAND 1590 SYSFM,0,0_/40,14:SYSHM:H0=FND(690):ID=INT(H0S K/10) 1600 REM FIRST BREAKS 1610 R=0:K=0:F2=0:NT=4 1620 FORI=0TO7:GOSUB1760:IFR=5THENI=8 1630 NEXT:K=K+1:IFR< 5ANDK< 5THEN1620 1640 REM EXTRA BREAKS 1650 F2=1:SYSFM,0_/0,3 2,14:SYSHM:H1=FND(690):IFH0-I D>H1THEN1720 1660 SYSFM,0,0,40,14 1670 I=(I+1)AND7:GOSUB1760:IFFTHEN1670 1680 IFF1=0THENPOKET,64:GOTO1670 1690 SYSFM,0,0,32,14:SYSHM:H2=FND(690) 1700 IFH1-H2<3THENPOKET,64:GOTO1660 1710 IFH0-ID<H2+1THENH1=H2:GOTO1660 1720 SYSFM,0,0,40,14 1730 RETURN 1740 : 1750 REM MAKE BREAK 1760 F1=0:F=1:J=0:DI=(RND(1)>.5) 1770 IFDITHEN1800 1780 Y0=Y0(I):X=X0(I):IFRND(1)>.5THENX=X1(I) 1790 GOTO1810 1800 X0=X0(I):Y=Y0(I):IFRND(1)>.5THENY=Y1(I) 1810 J=J+1:IFJ>NTTHENRETURN 1820 IFDITHEN1890 1830 Yl=(Y+FNR(Yl(l)-Y-2)+l):T=Y140+X+S 1840 IF(Y1>9ANDYK13)AND(X=18ORX=21)THEN1810 1850 IFPEEK(T+1)=64ORPEEK(T-1)=64THEN1810 1860 lFPEEK(T+40)<>64ORPEEK(T-40)<>640RPEEK(T)<>64 THEN1810 1870 IFF2ANDPEEK(T+1)=40ANDPEEK(T-1)=40THEN1810 1880 GOTO1930 1890 X1=X+FNR(XI(I)-X-2)+1:T=X1+Y*40+S:IF(XI>17AND XK22)AND(Y=9ORY=12)THEN1810 1900 IFPEEK(T+40)=64ORPEEK(T-40)=64THEN1810 1910 IFPEEK(T+1)<>640RPEEK(T-1)<>640RPEEK(T)<>64TH EN1810 1920 IFF2ANDPEEK(T+40)=40ANDPEEK(T-40)=40THEN1810

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	Machine Language Games	6

	1930 PL=0:F=0 1940 IFPEEK(T+40)=40ORPEEK(T-40)=40ORPEEK(T+1)=400 RPEEK(T-1)=40THENPL=40:F1=1 1950 IFF2THENPL=6 1960 POKET+C,13-(PL=40):POKET,PL:R=R+1:RETURN 1970 : 1980 REM SKILL/TITLE 1990 SK=1:PRINT"{CLR}"SPC(14)CHR$(142)"{GRN} {2 D0WN}ZUIDER{2 SPACES}ZEE":PRINTSPC(14)" {3 DOWN}RANK NUMBER" 2000 PRINTSPC(12)"{D0WN}{RVS} 1 {OFF} 2{2 SPACES}3 {2 SPACES}4{2 SPACES}5 " 2010 J=PEEK(JY):IFJ=127THEN2010 2020 PRINTSPC(9+SK3)"{UP}"SK"{LEFT} " 2030 IF(JAND4)=0THENSK=SK-1:IFSK<1THENSK=5 2040 IF(JAND8)=0THENSK=SK+1:IFSK> 5THENSK=1 2050 PRINTSPC(9+SK3)"{UP}{RVS}"SK"{LEFT} ":IF(JAN D16)THEN2010 2060 PRINT"{CLR}":POKE1026,SK:RETURN 2070 : 2080 REM DO INSTRUCTION SCREEN FOR POWER UP 2090 PRINT"{CLR}{4 DOWN}"SPC(14)"ZUIDER ZEE" 2100 PRINT"{DOWN} YOUR VILLAGE IN HOLLAND IS BUILT ON" 2110 PRINT" LAND RECLAIMED FROM THE SEA.{2 SPACES} HIGH" 2120 PRINT" DIKES HAVE KEPT THE WATER FROM FLOOD-" 2130 PRINT" ING YOUR LAND, BUT NOW A TERRIBLE" 2140 PRINT" STORM IS APPROACHING.{2 SPACES}HEAVY R AINS AND" 2150 PRINT" GIANT WAVES WILL UNDOUBTEDLY BREAK" 2160 PRINT" DOWN SECTIONS OF THE DIKES, FLOODING" 2170 PRINT" YOUR LAND.{2 SPACES}AS DIKEMASTER YOU {SPACE}ARE" 2180 PRINT" RESPONSIBLE FOR REPAIRING THE DIKES" 2190 PRINT" AND PUMPING OUT THE FLOODWATERS." 2200 PRINTSPC(5)"{2 DOWN}PRESS THE TRIGGER TO CONT INUE:":GOSUB2750 2210 : 2220 PRINT"{CLR}{DOWN} USE THE JOYSTICK TO DRIVE T HE TRUCK" 2230 PRINT" ALONG THE TOPS OF THE DIKES.{2 SPACES} YOU" 2240 PRINT" MAY NOT DRIVE OVER DIKES THAT ARE" 2250 PRINT" DECAYING.{2 SPACES}REMEMBER THAT YOU C AN" 2260 PRINT" REPAIR THE DIKES BY DUMPING DIRT ON" 2270 PRINT" THEM.{2 SPACESjTHE DIKES BEGIN TO DECA Y BEFORE"

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	V% Machine Language Games

	2280 PRINT" THERE ARE VISIBLE SIGNS OF DAMAGE." 2290 PRINT"{DOWN} PRESSING THE TRIGGER CAN HAVE ON E OF" 2300 PRINT" THREE EFFECTS:":PRINT"{DOWN} 1) PICK U P THE PUMP UNDER THE TRUCK." 2310 PRINT" 2) DROP THE PUMP UNDER THE TRUCK." 2320 PRINT" 3) PUT THE TRUCK IN REVERSE AND DUMP A ii 2330 PRINT"{4 SPACES}LOAD OF DIRT AT THE EDGE OF A DIKE." 2340 PRINT"{DOWN} THERE ARE TWO KEYBOARD CONTROLS: ii 2350 PRINT"{DOWN} 1) 'Fl* PAUSES THE GAME; PRESSIN G ANY" 2 360 PRINT"{4 SPACES}KEY WILL RESUME YOUR GAME." 2 370 PRINT" 2) 'Q' QUITS THE GAME." 2 380 PRINTSPC(6)"{DOWN}THE STORM IS APPROACHINGi {UP}":RETURN 2390 : 2400 REM NEXT LEVEL 2410 POKE834/0:PRINT"{HOME}{RVS}{BLU}{4 SPACES}YOU HAVE UNFLOODED THE ISLAND 1 i":POKE54283,0 2420 POKEFQ,20:POKEAD,0:POKESR, 240 2430 B=0:FORI=0TO9:B=B-(PEEK(52384+1)=0):NEXT:B=IN T(P1000SK)+B500 2435 FORSC=SCTOSC+BSTEP75:GOSUB560:POKECT,33:POKEC T,32:NEXT 2440 FORI=1TO750:NEXT 2450 PRINT"{CLR}{GRN}":POKE53272,6:POKE53280,0:POK E53281,0:POKE53269,0 2460 PRINT"SCORE:"MID$(STR$(INT(SC/10)10),2) 2470 PRINT"T2 DOWN} YOU HAVE SUCCEDED IN RECOVERIN G THE" 2480 PRINT" ENTIRE ISLAND.{2 SPACESjYOU ARE BEING {SPACE}PROMOTED" 2490 PRINT" BECAUSE OF THIS GREAT ACCOMPLISHMENTi" 2500 PRINT"{DOWN} ANOTHER, STRONGER STORM IS APPRO ACHING" 2510 PRINT" AND YOU HAVE BEEN GIVEN AN ISLAND THAT ii 2520 PRINT" HAS SUFFERED GREATER DAMAGE THAN YOUR" 2530 PRINT" FIRST ASSIGNMENT." 2540 PRINTSPC(15)"{DOWN}GOOD LUCK!" 2550 PRINTSPC(7)"{4 DOWNTPRESS THE TRIGGER TO BEGI N" 2560 POKE1027,(SC/10)AND255:POKE1028,SC/2560 2570 GOSUB2750:SK=SK+1:IFSK> 5THENSK=5 2580 POKE1026_/SK:RUN 2590 :

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	Machine Language Games	6

	2600 REM ISLAND FLOODED 2610 POKE834,0:PRINT"{HOME}{RVS}{BLU}{4 SPACES}THE ENTIRE ISLAND HAS FLOODEDM " : POKE54283 , 0 2620 POKEFQ,15:POKEAD,17:POKESR_# 250:POKECT,33 2630 FORI=1TO250:NEXT:POKECT,32:FORI=1TO750:NEXT 2640 POKE834,0:PRINT"{CLR}{GRN}":POKE53272,6:POKE5 3280,0:POKE53281,0:POKE53269,0 2650 PRINT"{DOWN}YOUR SCORE WAS:"MID$(STR$(INT(SC/ 10)*10),2) 2660 PRINT"{2 DOWN}YOU HAVE FAILED TO SAVE THE ISL AND" 2670 PRINT"AND HAVE BEEN RELIEVED OF YOUR" 2680 PRINT"POSITION AS DIKEMASTER." 2690 PRINT"{DOWN}PERHAPS ALL YOU NEED IS MORE PRAC TICE;" 2700 PRINT"WOULD YOU LIKE TO TRY AGAIN?" 2710 PRINTSPC(4)"{2 DOWN}PRESS THE TRIGGER TO BEGI N AGAIN" 2715 PRINT"{DOWN}{2 SPACES}'Q' TO QUIT AND ⁹V FOR INSTRUCTIONS" 2716 GETA$:IFA$="Q"THENPOKE648,4:POKE1024,0:SYS102 4 2717 IFA$<>"I"THEN2719 2718 GOSUB2090:PRINTSPC(6)"PRESS TRIGGER TO CONTIN UE":GOSUB2750:GOTO2640 2719 IFPEEK(JY)AND16THEN2716 2720 IF(PEEK(JY)AND16)=0THEN2720 2721 POKE1027_/0:POKE1028,0:SC=0:GOSUB2750:GOSUB199 0:RUN 2730 : 2740 REM TRIGGER? 2750 IFPEEK(JY)AND16THEN2750 2760 IF(PEEK(JY)AND16)=0THEN2760 2770 RETURN 2780 : 2790 REM SPRITE IMAGES 2800 REM TRUCK{2 SPACES}(U/d/l/R) 2810 DATA -25,60,-2,126,-2,126,-2,126,-2,126,-25 2820 DATA -25,126,-2,126,-2,126,-2,126,-2,60,-25 2830 DATA -25,63,-2,255,-2,255,-2,255,-2,63,-25 2840 DATA -25,252,-2,255,-2,255,-2,255,-2,252,-25 2850 : 2860 REM COPTER (U/D//L/UL/DL//R/UR/DR) 2870 DATA -10,60,-2,102,-2,102,-2,126,-2,126,-2,60 ,-2,60,-2,60,-2 288q DATA 24,-2,24,-2,24,-2,24,-2,24,-2,8,-2,56,-1 0 2890 DATA -10,56,-2,8,-2,24,-2,24,-2,24,-2,24,-2,2 4

	179



	y% Machine Language Games

	2900 DATA -2,60,-2,60,-2,60,-2,126,-2,126,-2,102,- 2,102,-2,60,-10, -63 2910 DATA -24,7,128,0,15,240,0,9,255,224,9,255,160 ,15,240,32,7,128,0,-21 2920 DATA -9,3,128,0,7,192,0,12,96,0,12,112,0,7,24 0,0,3,248,-2,124,-2 2930 DATA 60,-2,14,-2,7,-2,3,128,0,1,192,-2,96,-2, 192,-12 2940 DATA -14,192,-2,96,0,1,192,0,3,128,0,7,-2,14, -2,60,-2,124,0 2950 DATA 3,248,0,7,240,0,12,112,0,12,96,0,7,192,0 ,3,128,-10, -63 2960 DATA -22,1,224,4,15,240,5,255,144,7,255,144,0 ,15,240,0,1,224,-24 2970 DATA -10,3,128,0,7,192,0,12,96,0,28,96,0,31,1 92,0,63,128,0,62,-2,60,-2 2980 DATA 112,-2,224,0,1,192,0,3,128,0,6,-2,3,-14 2990 DATA -9,3,-2,6,-2,3,128,0,1,192,-2,224,-2,112 ,-2,60,-2,62,-2,63,128 3000 DATA 0,31,192,0,28,96,0,12,96,0,7,192,0,3,128 ,-12 3010 : 3020 REM PUMPS (U/d/l/R) 3030 DATA -22,24,-2,60,-2,126,-2,255,-2,219,-2,24, -2,24,-2,24,-19 3040 DATA -22,24,-2,24,-2,24,-2,219,-2,255,-2,126, -2,60,-2,24,-19 3050 DATA -22,24,-2,56,-2,112,-2,255,-2,255,-2,112 ,-2,56,-2,24,-19 3060 DATA -22,24,-2,28,-2,14,-2,255,-2,255,-2,14,- 2,28,-2,24,-19 3070 : 3080 REM COPTER ROTOR (FRAMES 0-7) 3090 DATA 0,24,-2,24,-2,24,-2,24,-2,24,-2,24,-2,24 ,-2,24,-2,24,-2,24,-2,24 3100 DATA -2,24,-2,24,-2,24,-2,24,-2,24,-2,24,-2,2 4,-2,24,-2,24,-2,24,0 3110 DATA -3,3,-2,3,-2,1,128,0,1,128,-2,192,-2,192 ,-2,96,-2,96,-2,48,-2,56 3120 DATA -2,28,-2,6,-2,6,-2,3,-2,3,-2,1,128,0,1,1 28,-2,192,-2,192,-3 3130 DATA -9,24,-2,12,-2,6,-2,3,-2,1,128,-2,192,-2 ,112,-2,24,-2,14,-2,3,-2,1 3140 DATA 128,-2,192,-2,96,-2,48,-2,24,-9 3150 DATA -18,96,-2,60,-2,7,-2,1,192,-2,126,-2,3,1 28,-2,224,-2,60,-2,6,-18 3160 DATA -30,255,255,255,-30 3170 DATA -20,6,-2,60,-2,224,0,3,128,0,126,0,1,192 ,0,7,-2,60,-2,96,-20

	180



	Machine Language Games

	3180 DATA -11,24,-2,48,-2,96,-2,192,0,1,128,0,3,-2 ,14,-2,24,-2,112,-2,192,0,1 3190 DATA 128,0,3,-2,6,-2,12,-2,24,-11 3200 DATA -5,192,-2,192,0,1,128,0,1,128,0,3,-2,3,- 2,6,-2,6,-2,12,-2 3210 DATA 24,-2,48,-2,96,-2,96,-2,192,-2,192,0,1,1 28,0,1,128,0,3,-2,3,-5 3220 : 3230 REM CHARACTER DATA 3240 DATA 0,255,204,0,51,255,204,0,51 3250 DATA 1,255,250,238,235,238,250,255,85 3260 DATA 2,253,189,237,173,237,189,253,85 3270 DATA 3,0,60,255,255,255,255,60,0 3280 DATA 4,85,255,255,168,255,255,69,69 3290 DATA 5,255,204,0,51,255,204,0,51 3300 DATA 6,0,0,0,0,0,0,0,0 3310 DATA 10,0,90,90,60,60,60,0,0 3320 DATA 11,255,255,255,255,255,255,255,255 3330 DATA 12,85,0,60,60,60,60,0,85 3340 DATA 31,255,255,255,255,255,255,255,255 3350 DATA 64,0,0,0,0,0,0,0,0 3360 : 3370 REM DIRECTIONAL DATA 3380 DATA 0,-1,0,1,-1,0,1,0 3390 DATA -40,40,-1,1 Program 2. Zuider Zee: Part 2. Machine Language Data to Use with MLX 49152 :076,021,192,076,175,192,220 49158 :076,060,193,076,139,193,231 49164 :076,023,202,076,205,193,019 49170 :076,226,194,032,116,193,087 49176 :141,000,205,032,116,193,199 49182 :141,000,206,032,116,193,206 49188 :133,002,032,116,193,133,133 49194 :010,169,000,141,137,003,246 49200 :141,179,002,133,013,169,173 49206 :001,141,143,003,141,178,149 49212 :002,133,009,162,003,024,137 49218 2 189,243,202,164,013,121,230 49224 :000,206,141,183,002,201,037 49230 :024,176,072,024,189,247,042 49236 :202,121,000,205,141,182,167 49242 :002,201,040,176,058,172,227 49248 :183,002,185,000,207,133,038 49254 :158,185,064,207,13 3,159,240 49260 :172,182,002,177,158,201,2 32 49266 :064,176,041,197,002,240,066

	181



	Machine Language Games

	49272 :037,165,002,032,043,193,080 49278 :238,178,002,208,003,238,225 49284 :179,002,164,009,173,182,073 49290 :002,153,000,205,17 3,183,086 49296 :002,153,000,206,230,009,232 49302 :076,158,192,169,001,141,119 49308 :137,003,202,016,160,230,136 49314 :013,166,009,228,013,208,031 49320 :150,169,000,141,143,003,006 49326 :096,160,000,132,018,032,100 49332 :116,193,164,018,153,180,236 49338 :002,200,192,004,208,241,009 49344 .-032,116,193, 133,002,032, 188 49350 :116,193,133,010,174,183,239 49356 :002,189,000,207,133,253,220 49362 :189,064,207,13 3,254,174,207 49368 :181,002,189,000,207,133,160 49374 :158,189,064,207,133,159,108 49380 -.172,180,002,165,002,032,013 49386 :025,193,200,204,182,002,016 49392 .-208,245,174,181,002,238,008 49398 :183,002,189,000,207,133,192 49404 2 158,189,064,207,133,159,138 49410 -.165,002,172,180,002,032,043 49416 :043,193,165,002,172,182,253 49422 2 002,032,043,193,232,236,240 49428 2 183,002,208,224,096,072,037 49434 2 145,253,165,254,072,073,220 49440 2 088,133,254,165,010,145,059 49446 2 253,104,133,254,104,145,007 49452 2 158,165,159,072,073,088,247 49458 2 133,159,165,010,145,158,052 49464 2 104,133,159,096,169,000,205 49470 2 141,178,002,141,179,002,193 49476 2 133,158,169,128,133,159,180 49482 2169,004,133,018,160,000,046 49488 2162,000,177,158,201,011,021 49494 2 240,012,201,031,176,008,242 49500 2 238,178,002,208,003,238,191 49506 2 179,002,230,158,208,002,109 49512 2 230,159,232,224,240,208,117 49518 2 227,198,018,208,223,096,056 49524 -.032,253,174,032,158,173,170 49530 2 165,013,240,003,104,104,239 49536 2 096,032,247,183,165,021,104 49542 2 208,246,165,020,096,160,005 49548 2 000,132,158,132,253,169,216 49554 2 208,133,159,169,160,133,084 49560 2 254,120,165,001,041,251,216

	182



	Machine Language Games

	49566 :133,001,177,158,145,253,001 49572 :200,208,249,230,159,230,160 49578 :254,165,159,201,216,208,093 49584 :239,165,001,009,004,133,215 49590 :001,088,17 3,000,221,041,194 49596 :252,009,001,141,000,221,044 49602 :169,008,141,024,208,169,145 49608 :024,141,022,208,096,173,096 49614 :173,002,205,136,003,176,133 49620 :081,169,000,141,175,002,012 49626 :169,020,141,145,003,173,101 49632 :027,212,041,031,201,022,246 49638 :176,247,170,232,142,169,086 49644 :002,173,027,212,041,063,242 49650 : 201, 038, 176, 247,170, 232, 026 49656 .-142,168,002,172,169,002,135 49662 :185,000,207,024,109,168,179 49668 :002,133,158,185,064,207,241 49674 :105,000,133,159,160,000,055 49680 :177,158,201,064,208,016,072 49686 :169,000,141,174,002,032,028 49692 :052,194,173,174,002,240,095 49698 :003,032,121,194,206,145,223 49704 :003,240,008,174,173,002,128 49710 :236,136,003,144,172,096,065 49716 :162,003,142,171,002,174,194 49722 :171,002,173,168,002,024,086 49728 :125,247,202,072,173,169,028 49734 :002,024,125,243,202,168,066 49740 :104,024,121,000,207,133,153 49746 :253,185,064,207,105,000,128 49752 :133,254,160,000,177,253,041 49758 :201,033,144,017,201,048,226 49764 :176,013,169,001,141,174,006 49770 :002,173,175,002,240,008,194 49776 :032,100,195,206,171,002,050 49782 :016,193,096,173,173,002,003 49788 :205,136,003,176,096,160,132 49794 :000,200,192,016,240,089,099 49800 :185,000,204,208,246,152,107 49806 :072,169,001,153,000,204,229 49812 :173,168,002,153,032,204,112 49818 :173,169,002,153,064,204,151 49824 :169,006,133,010,172,169,051 49830 :002,185,000,207,024,109,181 49836 .-168,002,133,158,185,064,114 49842 :207,105,000,133,159,104,118 49848 :024,105,064,072,160,000,097 49854 :032,043,193,238,173,002,103



	Machine Language Games

	49860 :104,132,159,010,038,159,030 49866 :200,192,003,208,248,133,162 49872 :158,165,159,024,105,160,211 49878 :133,159,169,000,160,007,074 49884 :145,158,136,016,251,096,254 49890 :173,173,002,240,119,169,078 49896 :000,141,140,003,173,136,057 49902 :003,074,141,145,003,169,005 49908 :001,141,175,002,173,027,251 49914 :212,041,015,201,015,240,206 49920 :247,170,232,142,177,002,202 49926 :189,000,204,240,083,188,142 4993 2 :064,204,140,169,002,189,012 49938 :032,204,141,168,002,024,077 49944 :121,000,207,133,158,185,060 49950 :064,207,105,000,133,159,186 49956 :160,000,177,158,201,064,028 49962 :240,019,169,000,141,174,017 49968 :002,032,052,194,173,174,163 49974 :002,240,006,17 3,140,003,106 49980 :240,032,096,174,177,002,013 49986 :169,000,157,000,204,188,016 49992 :064,204,185,000,207,133,097 49998 :158,185,064,207,133,159,216 50004 :169,064,188,032,204,145,118 50010 :158,206,17 3,002,206,145,212 50016 :003,208,149,096,173,027,240 50022 :212,205,144,003,144,001,043 50028 :096,120,165,001,041,254,017 50034 :133,001,17 3,177,002,024,112 50040 :105,064,160,000,132,254,067 50046 :010,038,254,200,192,003,055 50052 :208,248,133,253,165,254,113 50058 :024,105,160,133,254,174,220 50064 :171,002,224,002,208,018,001 50070 :160,255,200,192,008,240,181 50076 :088,177,25 3,208,247,169,018 50082 :25 5,145,25 3,076,245,195,051 50088 :224,003,208,016,160,008,019 50094 .-136,048,068,177,253,208,040 50100 :249,169,255,145,253,076,047 50106 :245,195,160,007,224,001,250 50112 .-208,025,177,253,162,000,249 50118 :232,224,008,240,010,010,154 50124 :176,248,189,064,203,017,077 50130 :253,145,253,136,016,234,223 50136 :076,245,195,224,000,208,140 50142 :022,177,253,162,000,232,044 50148 :224,008,240,010,074,176,192

	184



	Machine Language Games

	50154 1248,189,056,203,017,253,176 50160 :145,253,136,016,234,160,160 50166 :007,177,253,201,255 240,099 50172 :008,165,001,009,001,133,057 50178 :001,088,096,136,016,239,066 50184 :165,001,009,001,133,001,062 50190 :088,169,000,141,079,003,238 50196 :174,177,002,169,000,157,187 50202 :000,204,206,173,002,169,012 50208 :003,133,018,166,018,173,031 50214 :168,002,024,125,247,202,038 50220 :141,132,003,072,173,169,222 50226 :002,024,125,243,202,141,019 50232 :133,003,168,104,024,121,097 50238 :000,207,133,158,185,064,041 50244 :207,105,000,133,159,173,077 50250 :168,002,056,253,247,202,234 50256 2 141,134,003,072,173,169,004 50262 :002,056,253,243,202,141,215 50268 :135,003,168,104,024,121,135 50274 :000,207,133,253,185,064,172 50280 :207,105,000,133,254,160,195 50286 :000,177,158,141,141,003,218 50292 .-201,033,144,013,201,048,244 50298 :176, 009,177,253,141,142,252 50304 :003,201,048,144,058,198,012 50310 -.018,016,154,174,171,002,157 50316 2 173,169,002,024,125,243,108 50322 2 202,168,185,000,207,133,017 50328 2 253,185,064,207,133,254,224 50334 .-173,168,002,024,125,247,129 50340 2 202,168,177,253,072,172,184 50346 2 169,002,185,000,207,133,098 50352 2 253,185,064,207,133,254,248 50358 2 172,168,002,104,145,253,002 50364 2 076,029,197,172,169,002,065 50370 2 185,000,207,133,253,185,133 50376 2 064,207,133,254,172,168,174 50382 2 002, 169,160,145,253,169,080 50388 2 011,133,002,169,006,133,154 50394 2 010,173,132,003,141,000,165 50400 2 205,173,133,003,141,000,111 50406 2 206,032,043,192,173,178,030 50412 2 002,141,132,003,173,179,098 50418 2 002,141,133,003,173,137,063 50424 2 003,141,138,003,173,134,072 50430 2 003,141,000,205,17 3,135,143 50436 2 003,141,000,206,032,043,173 50442 2192,173,178,002,141,134,062



	f% Machine Language Games

	50448 :003,173,179,002,141,135,13V 50454 :003,17 3,137,003,141,139,106 50460 :003,169,001,141,140,003,229 50466 :141,079,003,096,162,009,012 50472 :189,160,204,208,036,188,001 50478 :128,204,185,000,207,133,135 50484 :251,185,064,207,133,252,120 50490 :188,096,204,177,251,201,151 50496 :004,240,014,169,010,145,134 50502 :251,165,252,07 3,088,133,008 50508 :252,169,001,145,251,202,072 50514 :016,212,096,120,173,066,253 50520 -.003,208,003,076,049,234,149 50526 :032,038,197,206,071,003,129 50532 :208,023,169,010,141,071,210 50538 :003,238,072,003,17 3,072,155 50544 :003,041,003,141,072,003,119 50550 :168,185,052,203,141,080,179 50556 :160,173,143,003,208,041,084 50562 :162,009,188,128,204,185,238 50568 :000,207,133,251,185,064,208 50574 :207,133,252,188,096,204,198 50580 :177,251,208,016,189,160,125 50586 :204,008,169,004,040,240,051 50592 .-002,169,012,188,096,204,063 50598 :145,251,202,016,217,169,142 50604 :000,141,067,003,173,000,044 50610 :220,201,127,208,008,169,087 50616 :000,141,078,003,076,092,062 50622 :199,141,068,003,041,016,146 50628 :208,007,169,001,141,067,021 50634 :003,208,005,169,000,141,216 50640 :078,003,162,000,169,001,109 50646 :044,068,003,240,009,010,076 50652 -.232,224,004,208,245,076,185 50658 :228,198,138,009,032,141,204 50664 :255,131,142,167,002,142,047 50670 :170,002,173,067,003,240,125 50676 :008,17 3,167,002,073,001,156 50602 :141,167,002,032,149,199,172 50688 :160,003,173,014,208,056,102 50694 -.249,036,203,141,064,003,190 50700 :144,008,173,016,208,041,090 50706 :128,208,001,024,173,064,104 50712 :003,106,074,074,141,064,230 50718 :003,173,015,208,056,249,222 50724 :040,203,074,074,074,141,130 50730 :065,003,032,199,199,208,236 50736 :006,136,016,206,076,092,068

	186



	Machine Language Games

	50742 :199,169,001,077,167,002,157 50748 :141,167,002,032,149,199,238 50754 :173,014,208,056,233,012,250 50760 :072,144,009,173,016,208,182 50766 :041,128,024,240,001,056,056 507 72 :104,106,074,074,141,064,135 50778 :003,072,17 3,015,208,056,105 50784 :233,040,074,074,074,141,220 50790 :065,003,168,185,000,207,218 50796 :133,251,185,064,207,133,057 50802 :252,104,168,169,064,145,248 50808 :251,173,067,003,240,099,185 50814 :17 3,079,003,240,094,173,120 50820 :143,003,208,089,173,083,063 50826 :003,208,084,174,170,002,011 50832 :173,065,003,056,253,251,177 50838 :202,201,002,144,070,201,202 50844 :023,176,066,168,173,064,058 50850 :003,056,253,255,202,201,108 50856 :001,144,054,201,039,176,015 50862 :050,024,121,000,207,133,197 50868 :251,185,064,207,105,000,224 50874 :133, 252,160,000,177,251,135 50880 :240,025,201,011,240,016,157 50886 :201,081,176,023,201,031,143 50892 :144,019,201,065,176,009,050 50898 :201,048,176,011,169,001,048 50904 :141,083,003,169,064,160,068 50910 :000,145,251,076,092,199,217 50916 :173,067,003,240,115,173,231 50922 :078,003,208,110,173,069,107 50928 :003,240,059,172,076,003,025 50934 :208,100,141,076,003,173,179 50940 :014,208,056,233,012,072,079 50946 :144,004,173,016,208,010,045 50952 :104,106,074,074,141,080,075 50958 :003,173,015,208,056,233,190 50964 :040,074,074,074,141,081,248 50970 :003, 173,170,002,141,082,085 50976 :003,169,000,141,069,003,161 50982 :169, 001,141,078,003,076,250 50988 :092,199,173,077,003,208,028 50994 :041,173,030,208,044,017,051 51000 :208,016,251,173,030,208,174 51006 :010,144,027,074,074,074,209 51012 :074,160,003,074,176,007,050 51018 :200,192,007,208,248,240,145 51024 :011,140,069,003,140,077,008 51030 2 003,169,001,141,078,003,225



	6	Machine Language Games

	51036 :173,069,003,240,049,170,02s 51042 :188,044,203,173,016,208,162 51048 :010,144,006,152,013,016,189 51054 :208,208,006,152,073,255,244 51060 :045,016,208,141,016,208,238 51066 :173,255,131,024,105,014,056 51072 :157,248,131,138,010,170,214 51078 :173,014,208,157,000,208,126 51084 :173,015,208,157,001,208,134 51090 :076,225,199,174,167,002,221 51096 .-208,003,206,015,208,224,248 51102 :001,208,003,238,015,208,063 51108 :224,002,208,013,206,014,063 51114 :208,016,008,173,016,208,031 51120 :041,127,141,016,208,224,165 51126 :003,208,013,238,014,208,098 51132 :208,008,173,016,208,009,042 51138 :128,141,016,208,096,174,189 51144 :065,003,189,000,207,024,176 51150 :109,064,003,133,251,189,187 51156 .-064,207,105,000,133,252,205 51162 :162,000,161,251,201,064,033 51168 :096,173,052,003,240,003,023 51174 :076,028,201,173,061,003,004 51180 :024,105,001,041,007,141,043 51186 :061,003,024,105,050,141,114 51192 :249,131,206,075,003,208,096 51198 :024,17 3,07 3,003,073,001,089 51204 :141,073,003,240,004,169,122 51210 :128,208,002,169,129,141,019 51216 :004,212,169,002,141,075,107 51222 :003,169,000,141,053,003,135 51228 :173,016,208,024,041,001,235 51234 :240,001,056,173,000,208,200 51240 :106,205,054,003,240,047,183 51246 :176,024,169,008,013,053,233 51252 -.003,141,053,003,238,000,234 51258 :208,208,032,169,001,013,177 51264 :016,208,141,016,208,076,217 51270 :093,200,169,004,013,053,090 51276 :003,141,053,003,206,000,226 51282 :208,016,008,169,254,045,014 51288 :016,208,141,016,208,173,082 51294 :001,208,074,205,055,003,128 51300 :240,027,176,014,169,002,216 51306 :013,053,003,141,053,003,116 51312 :238,001,208,076,129,200,196 51318 :169,001,013,053,003,141,242 51324 :053,003,206,001,208,173,000

	188



	Machine Language Games

	51330 1053,003,208,060,169,001,112 51336 :141,052,003,174,056,003,053 51342 2 224,010,176,045,189,160,178 51348 :204,208,040,169,001,157,159 51354 :160,204,188,128,204,185,199 51360 :000,207,133,251,185,064,232 51366 :207,133,252,188,096,204,222 513 72 2 169,011,145,251,165,252,141 51378 2 073,088,133,252,169,014,139 51384 2 145,251,169,030,141,070,222 51390 2 003,076,049,234,024,105,169 51396 2 035,141,248,131,174,053,210 51402 2 003,173,001,208,024,125,224 51408 2 025,203,141,003,208,173,193 51414 2 000,208,024,125,003,203,009 51420 2 141,002,208,173,016,208,200 51426 2 041,001,125,014,203,041,139 51432 2 001,010,141,068,003,173,116 51438 2 016,208,041,253,013,068,069 51444 2 003,141,016,208,173,016,033 51450 2 208,041,001,208,018,173,131 51456 2 000,208,201,005,176,011,089 51462 2 173,021,208,041,252,141,074 51468 2 021,208,076,025,201,173,204 51474 2 021,208,009,003,141,021,165 51480 2 208,076,049,234,169,128,120 51486 2 141,004,212,206,070,003,154 51492 2 240,000,169,255,141,057,130 51498 2 003,141,058,003,141,056,188 51504 2 003,173,016,208,024,041,001 51510 2 001,240,001,056,17 3,000,013 51516 2 208,106,074,074,141,059,210 51522 2 003,173,001,208,074,074,087 51528 2 074,141,060,003,162,009,009 51534 2 189,160,204,208,108,188,111 51540 2 128,204,140,055,003,185,031 51546 2 000,207,133,251,185,064,162 51552 2 207,133,252,188,096,204,152 51558 2 140,054,003,177,251,201,160 51564 2 004,240,080,173,059,003,155 51570 2 056,237,054,003,016,005,229 51576 2 073,255,024,105,001,032,098 51582 2 252,201,165,252,072,165,209 51588 2 251,072,173,060,003,056,235 51594 2 237,055,003,016,005,073,015 51600 2 255,024,105,001,032,252,045 51606 2 201,104,024,101,251,133,196 51612 2 2 51,104,101,252,133,252,225 51618 2 205,058,003,144,011,208,023



	Machine Language Games

	51624 :022,165,2s!,205,057,003,103 51630 :144,002,208,013,165,251,189 51636 :141,057,003,165,252,141,171 51642 :058,003,142,056,003,202,138 51648 :016,140,174,056,003,224,037 51654 :255,240,025,189,096,204,183 51660 :010,010,024,105,008,141,246 51666 :054,003,189,128,204,010,030 51672 :010,024,105,022,141,055,061 51678 .-003,076,236,201,169,001,140 51684 :141,054,003,169,072,141,040 51690 :055,003,169,000,141,052,142 51696 :003,141,073,003,169,002,119 51702 :141,075,003,076,049,234,056 51708 :134,251,162,000,133,252,160 51714 :168,240,011,169,000,024,102 51720 :101,252,144,001,232,136,106 51726 :208,247,134,252,166,251,248 51732 :133,251,096,169,143,141,185 51738 :024,212,169,255,141,014,073 51744 :212,141,015,212,169,240,253 51750 :141,020,212,169,129,141,082 51756 :018,212,169,050,141,000,122 51762 :212,169,017,141,005,212,038 51768 :169,241,141,006,212,169,226 51774 :000,141,173,002,141,076,083 51780 :003,141,077,003,141,061,238 51786 :003,141,03 5,208,169,006,124 51792 :141,032,208,169,001,141,004 51798 :046,208,141,039,208,141,101 51804 :040,208,141,071,003,141,184 51810 :079,003,169,166,141,014,158 51816 :208,169,132,141,015,208,209 51822 :169,000,141,000,208,169,029 51828 :144,141,001,208,169,032,043 51834 :141,255,131,169,005,141,196 51840 :034,208,141,001,212,169,125 51846 :128,141,064,207,162,000,068 51852 :142,000,207,189,000,207,117 51858 :024,105,040,157,001,207,168 51864 :157,026,207,189,064,207,234 51870 :105,000,157,065,207,157,081 51876 :090,207,232,224,024,208,125 51882 :228,169,000,160,000,153,112 51888 :000,204,174,000,004,208,254 51894 :021,153,000,136,153,000,133 51900 :137,153,000,138,153,000,001 51906 :139,153,000,140,153,000,011 51912 :141,153,000,142,200,208,020

	190





	Machine Language Games

	51918 :224,169,255,160,127,153,014 51924 :000,161,136,016,250,120,127 51930 :169,085,141,020,003,169,037 51936 :197,141,021,003,169,000,243 51942 :141,066,003,141,069,003,141 51948 :169,001,141,052,003,088,178 51954 :096,000,000,255,001,001,083 51960 :255,000,000,255,001,000,247 51966 :000,000,000,255,001,000,254 51972 -.000,000,000,253,254,253,252 51978 :000,002,001,002,000,000,015 51984 :000,000,255,255,255,000,013 51990 :000,000,000,000,254,002,022 51996 :000,001,254,002,000,000,029 52002 : 254, 002,010,014,012,012,082 52008 :040,040,039,041,001,002,203 52014 :004,008,016,032,064,128,042 52020 :102,060,102,195,001,003,003 52026 :007,015,031,063,127,255,044 52032 :128,192,224,240,248,252,068 52038 :254,255,080,255,084,251,225



			Appendix

		Beginner's Guide to Typing In Programs



	A A Beginner's Guide to Typing In Programs

	What Is a Program? A computer cannot perform any task by itself. Like a car without gas, a computer has potential, but without a program, it isn't going anywhere. Most of the programs in this book are written in a computer language called BASIC. BASIC is easy to learn and is built into all Commodore 64s. BASIC Programs Computers can be picky. Unlike the English language, which is full of ambiguities, BASIC usually has only one right way of stating something. Every letter, character, or number is significant. A common mistake is substituting a letter such as O for the numeral 0, a lowercase 1 for the numeral 1, or an uppercase B for the numeral 8. Also, you must enter all punctuation such as colons and commas just as they appear in the book. Spacing can be important. To be safe, type in the listings exactly as they appear. Braces and Special Characters The exception to this typing rule is when you see the braces, such as {DOWN}. Anything within a set of braces is a special character or characters that cannot easily be listed on a printer. When you come across such a special statement, refer to "How To Type In Programs." About DATA Statements Some programs contain a section or sections of DATA statements. These lines provide information needed by the program. Some DATA statements contain actual programs (called machine language); others contain graphics codes. These lines are especially sensitive to errors.

	195



	If a single number in any one DATA statement is mistyped, your machine could lock up, or crash. The keyboard and STOP key may seem dead, and the screen may go blank. Don't panic— no damage is done. To regain control, you have to turn off your computer, then turn it back on. This will erase whatever program was in memory, so always SAVE a copy of your program before you RUN it. If your computer crashes, you can LOAD the program and look for your mistake. Sometimes a mistyped DATA statement will cause an error message when the program is RUN. The error message may refer to the program line that READs the data. The error is still in the DATA statements, though. Get to Know Your Machine You should familiarize yourself with your computer before attempting to type in a program. Learn the statements you use to store and retrieve programs from tape or disk. You'll want to save a copy of your program, so that you won't have to type it in every time you want to use it. Learn to use your machine's editing functions. How do you change a line if you made a mistake? You can always retype the line, but you at least need to know how to backspace. Do you know how to enter inverse video, lowercase, and control characters? It's all explained in your computer's manuals. A Quick Review 1) Type in the program a line at a time, in order. Press RETURN at the end of each line. Use backspace or the back arrow to correct mistakes. 2) Check the line you've typed against the line in the book. You can check the entire program again if you get an error when you RUN the program. 3) Make sure you've entered statements in braces as the appropriate control key (see "How To Type In Programs" elsewhere in the book).

	196



			Appendix

		How to Type In Programs



	B How to Type In Programs

	Many of the programs which are listed in this book contain special control characters (cursor control, color keys, reverse video, etc.). To make it easy to know exactly what to type when entering one of these programs into your computer, we have established the following listing conventions. Generally, any Commodore 64 program listings will contain words in braces which spell out any special characters: {DOWN} would mean to press the cursor down key. {5 SPACES} would mean to press the space bar five times. To indicate that a key should be shifted (hold down the SHIFT key while pressing the other key), the key would be underlined in our listings. For example, S would mean to type the S key while holding the shift key. This would appear on your screen as a heart symbol. If you find an underlined key enclosed in braces (e.g., {10 N}), you should type the key as many times as indicated (in our example, you would enter ten shifted N's). If a key is enclosed in special brackets, B 3 , you should hold down the Commodore key while pressing the key inside the special brackets. (The Commodore key is the key in the lower-left corner of the keyboard.) Again, if the key is preceded by a number, you should press the key as many times as necessary. Rarely, you'll see a solitary letter of the alphabet enclosed in braces. These characters can be entered on the Commodore 64 by holding down the CTRL key while typing the letter in the braces. For example, {A} would indicate that you should press CTRL-A. About the quote mode: you know that you can move the cursor around the screen with the CRSR keys. Sometimes a programmer will want to move the cursor under program control. That's why you see all the {LEFT}'s, {HOME}'s, and {BLU}'s in our programs. The only way the computer can tell the difference between direct and programmed cursor control is the quote mode.

	199

Appendix

Once you press the quote (the double quote, SHIFT-2), you are in the quote mode. If you type something and then try to change it by moving the cursor left, you'll only get a bunch of reverse-video lines. These are the symbols for cursor left. The only editing key that isn't programmable is the DEL key; you can still use DEL to back up and edit the line. Once you type another quote, you are out of quote mode.

You also go into quote mode when you INSerT spaces into a line. In any case, the easiest way to get out of quote mode is to just press RETURN. You'll then be out of quote mode and you can cursor up to the mistyped line and fix it.

Use the following table when entering cursor and color control keys:

When You Read:

{CLR) (HOME}

(UP)

(DOWN)

(LEFT)

I RIGHT}

iRVS)

(OFF)

{BLK}

{WHT)

(RED)

{CYN}

I PUR)

(GRN)

(BLU)

lYEL}

Press:

See:

When You Read:

III

l?l


	Press: See
	1 COMMODORE 1 ]
	\| COMMODORE \| \| 2 \|
	__.
	\| COMMODORE \| \| 3 \|


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COMMODORE

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COMMODORE

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COMMODORE

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	I CTRL		1

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COMMODORE

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(F2 } (F3 } (F4 }


	fl
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SHIFT	f3	1


	CTRL		._ .

	CTRL		*

	CTRL		7

	CTRL		8

{ F5 ) (F6) I F7} ( F8)


			f5

	SHIFT		f5

			(7
	SHIFT		f7

200



	c Maze Generator_______ Charles Bond Translated to machine language by Gary E. Marsa and for the 64 by Gregg Peele.

	This program can be the basis for many excellent games. Here's a remarkably short algorithm which produces random mazes on your TV screen. To understand how it works, refer to the flowchart and Program 1. The following explanation should clarify the details. The Background Field The algorithm operates on a background field which must be generated on the screen prior to line number 210 in Program 1. The field must consist of an odd number of horizontal rows, each containing an odd number of cells: a rectangular array. It's convenient to think of the field as a two-dimensional array with the upper-left corner having coordinates X = 0 and Y = 0, where X is the horizontal direction and Y is vertical. No coordinates are used to identify absolute locations by the program, but the concept is useful in configuring the field. Given that the upper-left cell of the field has coordinates 0,0, then the terminal coordinates both horizontally and vertically must be even numbers. In addition, the background field must be surrounded on all sides by memory cells whose contents are different from the number used to identify the field. That is, if the field consists of reversed (or inverse video) spaces, then the number corresponding to that character must not be visually adjacent to the field. This could happen inadvertently if the screen RAM and system ROM have contiguous addresses. A sufficient precaution is to avoid covering the entire screen with field. Leave at least one space at the beginning or end of each line and, in general, leave the uppermost and lowermost lines on the screen blank.

	203



	Appendix

	The Maze Generator The creation of the maze begins by placing a special marker in a suitable starting square. The program here always begins at the square just inside the upper-left cell of the previously drawn field. (Note that with our coordinate scheme this would be cell 1,1.) Any cell with odd-numbered coordinates would work, however, as long as it is internal to the field. Next, a random direction is chosen by invoking the random number generator in your machine and producing an integer from 0 to 3. This integer, with the aid of a short table, determines a direction and a corresponding cell just two steps away from the current cell. This new cell is examined (PEEKed) to see if it is part of the field. If it is, the direction integer is put there as a marker, and the barrier between it and the current cell is erased. In addition, the pointer to the current cell is moved to point to the new one. This process is repeated until the new cell fails the test; that is, it is not a field cell. When this happens, the direction vector is rotated 90 degrees and the test is repeated. Thus, the path carved out of the field will continue until a dead end is reached. A dead end, incidentally, could occur in as few as five steps. When it does occur, we can make use of the markers which were dropped along the way Hansel and Gretel style. These can be checked to determine which direction we came from, so that we can back up and look for untrodden paths. So long as none can be found, the program will back up, one step at a time, erasing the markers as it goes. When a new direction can be taken, the pointer is set off in that direction, and the process continues as before. Ultimately, the pointer will return to the start, a condition which is detected by the recovery of the special starting (now ^//ending^,/) marker. This cell is then blanked and the program is done, leaving the pointer as it was at the start. The Program The direction table set up in lines 100 and 110 converts an integer to an address offset. In this case (40-column screen), we wish to step two cells to the right, up, left, or down. Line 120 contains the variable SC, which is the memory address of the start of screen RAM. Lines 130-160 establish the background field on the screen. The rest of the program draws the maze, as previously

	204



	Appendix	C

	explained. Line 310 is simply a convenient stopping point which prevents the screen from scrolling. It may not be immediately obvious that this algorithm always produces a maze with only one nontrivial path between any two points, or that the maze will always be completely filled, but this can be proved. While the proofs will not be provided here, math buffs may find it interesting that for a maze of any size there will be exactly: (H-D(V-l) -1 empty cells in the completed maze, 2 where H is the number of cells in each field row and V is the number of rows. An interesting feature of this algorithm is that it works equally well in certain types of nonrectangular fields. U-shaped fields or fields with holes in them are quite suitable—as long as certain restrictions are observed. Just make sure that the coordinates of the upper-left and lower-right cells of any cut-out area are pairs of odd numbers. Also, if there is a single row of field cells between any cut-out areas and the outside of the original field, it may be removed. Machine Language Mazes Program 2 is a machine language translation of Program 1. It is in the form of a BASIC loader. It can be inserted into any BASIC program just as Program 1. Program 3 is the assembly listing of the machine language routine found in Program 2. The Mouse The subroutine on lines 1000 to 1020 of Program 1 produces an artificial mouse which roams the maze endlessly. The mouse adheres to a "left-hand rule" when a choice of directions is possible. That is, when it is confronted with a branch-point, it will move off to the left, if possible. Otherwise, it will go forward. When no choice is available, it will turn around. These lines are unnecessary for the creation of the maze and may be deleted. Programs 2 and 3 do not contain the mouse. Program 1. BASIC Maze Generator 100 DIMA(3) 110 A(0)=2:A(1)=-80:A(2)=-2:A(3)=80 120 WL=160:HL=32:SC=1024:A=SC+81

	205



	Appendix

	130 PRINT"{CLR}" 140 F0RI=1T023 150 PRINT" {RVSHWHT} {39 SPACES}" 160 NEXTI 210 P0KEA,4 2 20 J=INT(RND(1)4):X=J 2 30 B=A+A(J):IFPEEK(B)=WLTHENPOKEB,J:POKEA+A(J)/2, HL:A=B:GOTO220 240 J=(J+1)-(J<3):IFJ<>XTHEN230 250 J=PEEK(A):P0KEA,HL:IFJ<4THENA=A-A(J):GOTO220 310 GETC$:IFC$=""THEN310 1000 POKEA_/81:J=2 1010 B=A+A(J)/2:IFPEEK(B)=HLTHENPOKEB,81:POKEA,HL: A=B:J=(J+2)+4(J>D 1020 J=(J-1)-4(J=0):GOTO1010 Program 2. Machine Language Maze Generator 10 I=49152:IF PEEK(1+2)=216THENSYS49160:END 20 READ A:IF A=256 THENSYS49160:END 30 POKE I_/A:I=I+l:GOTO 20 49152 DATA 1,0,216,255,255,255,40 49160 DATA 0,169,81,133,251,169,40 49168 DATA 133,253,169,4,133,252,133 49176 DATA 254,169,147,32,210,255,162 49184 DATA 0,160,0,169,160,145,253 49192 DATA 200,192,39,208,249,24,165 49200 DATA 253,105,40,133,253,144,2 49208 DATA 230,254,232,224,23,208,229 49216 DATA 160,0,169,4,145,251,169 49224 DATA 255,141,15,212,169,128,141 49232 DATA 18,212,173,27,212,41,3 49240 DATA 133,173,170,10,168,24,185 49248 DATA 0,192,101,251,133,170,185 49256 DATA 1,192,101,252,133,171,24 49264 DATA 185,0,192,101,170,133,253 49272 DATA 185,1,192,101,171,133,254 49280 DATA 160,0,177,253,201,160,208 49288 DATA 18,138,145,253,169,32,145 49296 DATA 170,165,253,133,251,165,254 49304 DATA 133,252,76,62,192,232,138 49312 DATA 41,3,197,173,208,189,177 49320 DATA 251,170,169,32,145,251,224 49328 DATA 4,240,26,138,10,168,162 49336 DATA 2,56,165,251,249,0,192 49344 DATA 133,251,165,252,249,1,192 49352 DATA 133,252,202,208,238,76,62 49360 DATA 192,169,1,160,0,153,0 49368 DATA 216,153,0,217,153,0,218 49376 DATA 153,0,219,200,208,241,96,256

	206

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C0B7 A9 01	LDA #$01
C0B9 A0 00	LDY #$00
C0BB 99 00 D8	STA $D800,	Y
C0BE 99 00 D9	STA $D900,	Y
C0C1 99 00 DA	STA $DA00,	Y
C0C4 99 00 DB	STA $DB00,	Y
C0C7 C8	INY
C0C8 D0 Fl	BNE $C0BB
C0CA 60	RTS
Maze Generator Flowchart

ESTABLISH STARTING CELL

LEAVE MARKER, ERASE BARRIER, BUMP POINTER



			Appendix

		Do You Want to Write Your Own Games?



	D Do You Want to Write Your Own Games? Orson Scott Card

	I remember when videogames first reached my town back in the early seventies. A friend and I dropped a few quarters into a Pong machine and had a great time. But all in all, we preferred playing Ping-Pong on a real table. But then, in a theater lobby, we met Breakout, and it changed my life. I became a dedicated videogamer from that time forward. Because there on a TV screen—not even a color screen, then, just black-and-white with colored plastic strips—the videogame was offering an experience that I couldn't get anywhere else. The speed and the concept both were something entirely new. Everybody knows where it went from there. Turn Breakout's paddle into a spaceship, give the bricks a different shape, and let them march down the screen at you, and you have Space Invaders. Turn Breakout's paddle into a race car and let it drive over dots instead of bricks, and you have the earliest gobble games. The shoot-outs and gobble games, the climbing games and the simulations—they have all become more sophisticated. Now, on your own TV at home, you can have the little airplanes of "Richthofen's Revenge" flying around. And you typed the game into your computer yourself. Getting Behind the Games If you're like me, however, playing was never really enough. Right from the beginning, I wondered how it was done. I knew nothing about computers then—like many people, I thought computers were for people who were good in math or interested in engineering, and I was definitely neither. But for the first time I wanted to have whatever abilities it took to program computers. Because I wanted to make my own games.

	213



	I wanted to create a game where I could handle old-time sailing ships through currents and winds to explore different islands and conduct sea battles. I wanted a game where I could build cities and design traffic flow patterns, create the image of a city's life. I wanted to have the power of a computer to create whatever world I wanted, and whatever game I wanted to play within that world. But I knew it would never happen. I wasn't good in math or interested in engineering, and to people like me computers would never be anything but big black boxes. Unlocking the Little Black Box The big black boxes have changed, haven't they? You can treat your 64 as a black box, if you want—plug in a game on a ROM cartridge and away you go. But for most games, you still need to type things like LOAD and RUN. And for the games in this book, you need to type in entire programs. And if it hasn't occurred to you before, it certainly should be plain now. You have the equipment to program all those games you have always wished you could play. Your Commodore 64 can do almost everything the videogames in the arcade can do. Best of all, though, it can do things that have never been done before. It can display worlds that you create, and carry out actions that you designed. And as for the myth that programmers have to be good in math or engineering—you don't believe that anymore, do you? My wife still has to balance the checkbook for me and I can't tell a circuit diagram from a plate of vermicelli, but I have written games that actually work, using BASIC and machine language both. And like those old-time ads ("My Friends Laughed When I Sat Down At The Piano"), I assure you that if I can do it, anybody can. How to Learn How to Program Games Unfortunately, you won't find a night school class in videogame programming. Colleges and high schools tend to teach programming with a business or mathematical slant. They rarely teach much about the graphics and sound techniques at the heart of game programming. So the best way to learn programming is to find a friend who's an expert videogame programmer and get him to teach

	214



	Appendix	D

	you, step by step, how to solve the problems you run into trying to program your first game. Because you can only learn to program by programming, and having an expert (and patient) friend gets you through the rough places. The second best way is books. There are books that teach you BASIC programming for the Commodore 64, reference books that give you valuable information about memory locations and special techniques, books that teach machine language programming for the 6510 that runs your 64, and even a book called Creating Arcade Games on the Commodore 64, which sounds like exactly the book you want. (Before I give you my full list of recommended reading, I'd better explain something. This list will include mostly books published by COMPUTE! Books, which is the publisher of COMPUTEI's First Book of Commodore 64 Games. However, this is not merely shameless self-promotion. Wherever I knew of a valuable teaching or reference book by another publisher, I have listed it. But the Commodore 64 is such a new computer that at the time of this writing, most publishers don't have their Commodore 64 books out yet. In fact, many of the books on my list haven't been published yet, either. But because I'm an editor at COMPUTE! Books, I know all about our books that are at the printer or in production or still coming, a chapter at a time, from authors in California, Michigan, Utah, Virginia, Pennsylvania, and New Jersey Therefore, I can include those books on the list and promise you that they'll help you learn programming. But I can't tell you about forthcoming books by other publishers because, unfortunately, in the world of publishing we don't always tell each other what we have planned. By the time you read this, there may be a hundred other books that can help you; this list will only tell you about the ones I know.) In the following list, an asterisk () marks the books that are useful only if you are planning to use machine language. BASIC Programming.* If you're new at programming, here are some books that can help supplement the manuals published by Commodore. Camp, David. Creating Arcade Games on the Commodore 64. Greensboro, North Carolina: COMPUTE! Books. Chamberlain, Craig. All About the Commodore 64. 2 vols. COMPUTE! Books. Heilborn, John and Ron Talbott. Your Commodore 64: A Guide to the Commodore 64 Computer. Berkeley, California: Osborne/ McGraw-Hill. 215



	COMPUTEl's First Book of Commodore 64. Commodore 64 Programmer's Reference Guide. West Chester, Pennsylvania: Commodore Business Machines, Inc. Graphics and Sound Techniques. Once you've mastered the basics of BASIC, you can get into the fascinating techniques of moving shapes and colors on the TV screen and creating sounds from the TV speaker. This is an area where the Commodore 64 is different from every other computer, even its little brother, the VIC-20. Heilborn, John. COMPUTEl's Reference Guide to Commodore 64 Graphics. Heilborn, John. COMPUTEl's Reference Guide to Commodore 64 Sound. COMPUTERS First Book of Commodore 64 Sound and Graphics. Reference Books. These are books that give you detailed information about features and key memory locations of the Commodore 64. Many of these features are only usable in machine language, but others are valuable to BASIC programmers as well. Heeb, Dan. The Commodore 64 Tool Kit: Kernal Routines.* COMPUTE! Books. Heeb, Dan. The BASIC Tool Kit: Commodore 64 and VIC-20.* COMPUTE! Books. Leemon, Sheldon. Mapping the Commodore 64. COMPUTE! Books. Learning Machine Language. These are books that help you learn how to put real speed and complex but smooth animation into your videogames. Fernandez, Judi N., Donna N. Tabler, and Ruth Ashley. 6502 Assembly Language Programming. New York: John Wiley and Sons. Leventhal, Lance A., and Winthrop Saville. 6502 Assembly Language Subroutines. Osborne/McGraw-Hill. Mansfield, Richard. Machine Language for Beginners. COMPUTE! Books. Zaks, Rodnay Programming the 6502. Berkeley, California: Sybex.

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