Doubleback
C000: 0F BB CLR highScore ; First RESET comes here. Clear ... C002: 0F BC CLR highScore+1 ; ... high-score ; Reset: ; After the first boot, the RESET handler is modified to come here. This is also ; where the BREAK key jumps to. (Maybe BREAK should skip rebuilding the mask table ; and jump to C031). C004: 12 NOP ; Required by BASIC ROM RESET handler C005: 1A 50 ORCC #$50 ; Disable IRQ C007: 10 CE 01 50 LDS #$0150 ; Stack C00B: 30 8C F6 LEAX Reset,PC ; RESET button ... C00E: 9F 72 STX $72 ; ... now comes to C004
The Mask Table
There are 4 pixels per memory byte: aa_bb_cc_dd
The value 00 is considered transparent. When an image is blitted to the screen, any pixels with value 00 are left unchanged at the destination. In order to set the non-zero bits, a mask is needed to zero-out the pixels at the destination. The pixel mask value is 11 for pixel value 00 and 00 for any other pixel value.
For instance: 00_01_10_00 has two visible pixels in the middle and two transparents on the ends
The mask: 11_00_00_11 this would AND out any 1s at the destination allowing the new value to be ORed into the destination
Building the mask on the fly is tedious (costly in time). Instead, the code builds a 256-value lookup table to get the mask from the pixel pattern. TABLE[$18] = $C3 for the example above.
; Build the bit mask table from 0380 to 0390 C010: 8E 03 80 LDX #$0380 ; Start of mask table C013: 5F CLRB ; Start with ... C014: 34 04 PSHS B ; ... entry 0 C016: A6 E4 LDA ,S ; Table entry index C018: E6 E4 LDB ,S ; Table entry value C01A: C4 AA ANDB #$AA ; Keep the upper bit of each pixel C01C: 54 LSRB ; Copy to lower bit of each pixel C01D: E7 86 STB A,X ; Accumulate that C01F: E6 E4 LDB ,S ; Table entry value C021: C4 55 ANDB #$55 ; Keep the lower bit of each pixel C023: 58 ASLB ; Copy to upper bit of each pixel C024: EA 86 ORB A,X ; Accumulate that C026: EA E4 ORB ,S ; OR in the original bits C028: 53 COMB ; 1's to 0 for an AND mask C029: E7 86 STB A,X ; Store the entry C02B: 6C E4 INC ,S ; Do all ... C02D: 26 E7 BNE $C016 ; ... 256 entries C02F: 35 04 PULS B ; remove stack temporary SplashScreen: C031: 17 0A 1E LBSR ClearScreen ; Clear the screen C034: 17 0A 98 LBSR SetVideoMode ; Set the graphics mode C037: CC 1C 46 LDD #$1C46 ; Screen coordinates C03A: 33 8D 0D 33 LEAU StrCopyright1,PC ; Print ... C03E: 17 09 02 LBSR PrintChars ; ... copyright line 1 C041: CC 14 4E LDD #$144E ; Screen coordinates C044: 33 8D 0D 3A LEAU StrCopyright2,PC ; Print ... C048: 17 08 F8 LBSR PrintChars ; ... copyright line 2 C04B: CC 14 56 LDD #$1456 ; Screen coordinates C04E: 33 8D 0D D1 LEAU StrCopyright3,PC ; Print ... C052: 17 08 EE LBSR PrintChars ; ... copyright line 3
Cursive Doubleback
>> How is the cursive "doubleback" drawn on the screen?
The start screen has the word "doubleback" written in large cursive letters across the screen. The code also draws a reflected version (left/right and up/down) below the first.
The forward drawing begins at corrdinate (1F,18). The code uses a table of directions at CEC3 to move the drawing from pixel to pixel. Each entry in the table is a 3 bits specifying one of 8 directions (N,S,E,W,NE,SE,NW,SW).
There is an interactive demonstration of the cursive drawing below at CEC3.
; Cursive "doubleback" C055: 8E 00 E4 LDX #$00E4 ; Utility object structure C058: 86 1F LDA #$1F ; Set ... C05A: A7 84 STA ,X ; ... X coordinate C05C: 86 18 LDA #$18 ; Set ... C05E: A7 02 STA 2,X ; ... Y coordinate C060: 33 8D 0E 5F LEAU $CEC3,PC ; Cursive "doubleback" data C064: 34 04 PSHS B ; Space on stack for counter C066: C6 05 LDB #$05 ; Each word has 3*5 = 15 data points C068: E7 E4 STB ,S ; Store the count C06A: EC C1 LDD ,U++ ; Get the next 5 data points C06C: 27 42 BEQ $C0B0 ; No more ... we are done C06E: 34 06 PSHS B,A ; Hold the data points C070: C4 07 ANDB #$07 ; Lower 3 bits C072: 58 ASLB ; 2 bytes per C073: 31 8D 0E B6 LEAY DirTable,PC ; Offset table C077: EC A5 LDD B,Y ; Get X and Y offsets C079: AB 84 ADDA ,X ; Add X offset C07B: EB 02 ADDB 2,X ; Add Y offset C07D: A7 84 STA ,X ; Nex X position C07F: E7 02 STB 2,X ; New Y position C081: 40 NEGA ; Mirror ... C082: 8B 80 ADDA #$80 ; ... X ... C084: A7 01 STA 1,X ; ... coordinate C086: 50 NEGB ; Mirror ... C087: CB 3C ADDB #$3C ; ... Y ... C089: E7 03 STB 3,X ; ... coordinate C08B: 34 50 PSHS U,X ; Hold data pointer and screen pointer C08D: 17 08 CF LBSR SetPixel ; Draw top pixel C090: 30 01 LEAX 1,X ; Skip over to 2nd screen pointer C092: 17 08 CA LBSR SetPixel ; Draw bottom (reflected) pixel C095: E6 84 LDB ,X ; Is the X ... C097: C4 01 ANDB #$01 ; ... coordinate odd? C099: 26 03 BNE $C09E ; No ... skip the pause C09B: 17 0A 51 LBSR WaitVBlank ; Yes ... slight pause C09E: 35 50 PULS X,U ; Restore the data pointer and the screen pointer C0A0: 35 06 PULS A,B ; Pop the data points C0A2: 6A E4 DEC ,S ; All 5 datapoints done? C0A4: 27 C0 BEQ $C066 ; Yes ... reload next five C0A6: 44 LSRA ; No ... C0A7: 56 RORB ; ... shift ... C0A8: 44 LSRA ; ... over ... C0A9: 56 RORB ; ... next ... C0AA: 44 LSRA ; ... data ... C0AB: 56 RORB ; ... point C0AC: 34 06 PSHS B,A ; Hold current data C0AE: 20 C0 BRA $C070 ; Do next point C0B0: 35 04 PULS B ; Remove the stack counter ; Select 1 or 2 players C0B2: CC 28 3A LDD #$283A ; Print coordinates C0B5: 33 8D 0C 57 LEAU Str1or2Players,PC ; Print ... C0B9: 17 08 87 LBSR PrintChars ; ... "1 or 2 Players" C0BC: AD 9F A0 0A JSR [JOYIN] ; Read the joysticks C0C0: 0F B4 CLR numPlayers ; Number of players = 1 C0C2: CE 0C 2A LDU #$0C2A ; Screen coordinate for the underline for 1 or 2 C0C5: 6F C4 CLR ,U ; Erase the 1 underline C0C7: 6F 43 CLR 3,U ; Erase the 2 underline C0C9: B6 01 5A LDA $015A ; Player one X axis C0CC: 81 1F CMPA #$1F ; Left or right of middle? C0CE: 2F 04 BLE $C0D4 ; Left ... C0D0: 0C B4 INC numPlayers ; Number of players = 1 C0D2: 33 43 LEAU 3,U ; U points to 2 underline C0D4: 6A C4 DEC ,U ; Underline the 1 or 2 with a white 4 pixels C0D6: 17 0A 16 LBSR WaitVBlank ; Wait for VBLANKing C0D9: F6 FF 00 LDB PIA0_DA ; Button ... C0DC: C4 01 ANDB #$01 ; ... pressed? C0DE: 26 DC BNE $C0BC ; No ... keep waiting ; Clear the scores and get ready for three rounds C0E0: 0F B7 CLR p1Score ; Clear player ... C0E2: 0F B8 CLR p1Score+1 ; ... one score C0E4: 0F B9 CLR p2Score ; Clear player ... C0E6: 0F BA CLR p2Score+1 ; ... two score C0E8: C6 03 LDB #$03 ; Start with ... C0EA: D7 B5 STB numLives ; ... three lives
Game Loop
This is the game's main loop. This code calls on the main game loop 3 times for each player. Once the game is over, this code updates the high score if needed. Finally, it prints "Game Over" and waits for a button before restarting way up at the splash screen code.
; All lives -- both players C0EC: 0F B6 CLR player ; Player 0 C0EE: 17 00 3E LBSR PlayRound ; Play one round for player 0 C0F1: 0D B4 TST numPlayers ; Two player game? C0F3: 27 05 BEQ $C0FA ; No ... skip second player C0F5: 0C B6 INC player ; Player 1 C0F7: 17 00 35 LBSR PlayRound ; Play one round for player 1 C0FA: 0A B5 DEC numLives ; Subtract one from lives C0FC: 26 EE BNE $C0EC ; Go back for all lives ; ; Update high scores C0FE: DC B7 LDD p1Score ; Player 1 score C100: 10 93 BB CMPD highScore ; Beat the high score? C103: 23 02 BLS $C107 ; No ... move on C105: DD BB STD highScore ; Change the high score C107: DC B9 LDD p2Score ; Player 2 score C109: 10 93 BB CMPD highScore ; Beat the high score? C10C: 23 02 BLS $C110 ; No ... move on C10E: DD BB STD highScore ; Change the high score C110: DC BB LDD highScore ; Print ... C112: CE 04 EE LDU #$04EE ; ... high score at top ... C115: 17 05 13 LBSR DrawNumber ; ... of screen ; ; Print "Game Over" and wait for a button C118: CC 2C 28 LDD #$2C28 ; Print coordinates C11B: 33 8D 0B A0 LEAU StrGameOver,PC ; Print ... C11F: 17 08 21 LBSR PrintChars ; ... "Game Over" C122: 17 09 9B LBSR CheckForBreak ; Check for break C125: F6 FF 00 LDB PIA0_DA ; Wait for ... C128: C4 01 ANDB #$01 ; ... button ... C12A: 26 F6 BNE $C122 ; ... press ... C12C: 16 FF 02 LBRA SplashScreen ; Start a new game
Play One Round
This code plays one round for either of the players. The round ends when the player runs into a game object.
PlayRound: ; ; Clear the screen and init the round variables C12F: C6 FF LDB #$FF ; Fill screen ... C131: 17 09 1F LBSR FillScreen ; ... with white {} C134: 0F BE CLR endOfPlayer ; Offset in player's line buffer (0x200) C136: 0F D1 CLR nextObjTime ; C138: 0F CE CLR liveObjCnt ; C13A: 0F D0 CLR totalLoops ; C13C: 0F C7 CLR hasLoopScore ; Not showing a loop score C13E: 0F D6 CLR flashType ; Flash player "word" is off C140: 0F CF CLR skullCount ; C142: C6 28 LDB #$28 ; Reload counter for ... C144: D7 D5 STB flashCount ; ... flashing player "word" ; ; Print the player number so they both know whose turn it is C146: CC 2C 28 LDD #$2C28 ; Screen coordinates C149: 33 8D 0A FF LEAU StrPlayer,PC ; Graphics for "Player" C14D: 17 07 F3 LBSR PrintChars ; Print "player" C150: CC 44 28 LDD #$4428 ; Screen coordinates C153: 33 8D 0B 26 LEAU StrOne,PC ; Graphics for "one" C157: 0D B6 TST player ; Player 0 or 1? C159: 27 06 BEQ $C161 ; Player 0 ... keep the "one" C15B: 86 46 LDA #$46 ; Move "two" over a hair C15D: 33 8D 0B 3D LEAU StrTwo,PC ; Graphics for "two" C161: 17 07 DF LBSR PrintChars ; Print the player (one or two) ; ; Play the song that goes with the life number (1, 2, or 3) C164: D6 B5 LDB numLives ; What life-number are we on? C166: 33 8D 0E 1B LEAU MusicThirdLife,PC ; Song for "3rd life" C16A: 5A DECB ; Is this the last life? C16B: 27 0B BEQ $C178 ; Yes ... play this song C16D: 33 8D 0D F0 LEAU MusicSecondLife,PC ; Song for "2nd life" C171: 5A DECB ; Is this the second life? C172: 27 04 BEQ $C178 ; Yes ... play this song C174: 33 8D 0D C5 LEAU MusicFirstLife,PC ; Song for 1st life C178: 17 09 03 LBSR PlaySong ; Play the song ; ; Now that the song is done, clear the playfied and draw its border C17B: 17 08 E5 LBSR DrawPlayfiled ; C17E: C6 02 LDB #$02 ; X/Y coordinate ... C180: 34 04 PSHS B ; ... temporary C182: 8E 00 E4 LDX #$00E4 ; Utility object to draw border C185: C1 56 CMPB #$56 ; Left/Right side is shorter C187: 2E 12 BGT $C19B ; Beyond the bounds of up/down ... skip up/down lines C189: E7 02 STB 2,X ; Set the Y coordinate C18B: C6 02 LDB #$02 ; X coordinate ... C18D: E7 84 STB ,X ; ... is 2 C18F: 17 07 CD LBSR SetPixel ; Draw the line down left side C192: C6 7E LDB #$7E ; X cooridante ... C194: E7 84 STB ,X ; ... is right side C196: 17 07 C6 LBSR SetPixel ; Draw the line down right side C199: E6 02 LDB 2,X ; Counter now ... C19B: E7 84 STB ,X ; ... in the X coordinate C19D: C6 02 LDB #$02 ; Top Y ... C19F: E7 02 STB 2,X ; coordinate C1A1: 17 07 BB LBSR SetPixel ; Draw the line across the top C1A4: C6 56 LDB #$56 ; Bottom ... C1A6: E7 02 STB 2,X ; ... Y coordinate C1A8: 17 07 B4 LBSR SetPixel ; Draw the line across the bottom C1AB: 6C E4 INC ,S ; Increment the counter C1AD: E6 E4 LDB ,S ; New counter value C1AF: C1 7E CMPB #$7E ; All edge pixels drawn? C1B1: 23 CF BLS $C182 ; No ... go do them all C1B3: 35 04 PULS B ; Pop the counter ; ; Print the player scores below the playfield C1B5: 4F CLRA ; X coordinate C1B6: C6 58 LDB #$58 ; Y coordinate C1B8: 33 8D 0A 90 LEAU StrPlayer,PC ; Print "player" at bottom ... C1BC: 17 07 84 LBSR PrintChars ; ... of screen C1BF: CC 18 58 LDD #$1858 ; Coordinates for "one" C1C2: 33 8D 0A B7 LEAU StrOne,PC ; Graphics for "one" C1C6: 17 07 7A LBSR PrintChars ; Print "one" after "player" C1C9: 0D B4 TST numPlayers ; One are two players? C1CB: 27 0A BEQ $C1D7 ; Just one ... skip the "two" C1CD: CC 52 58 LDD #$5258 ; Coordinates for "two" C1D0: 33 8D 0A CA LEAU StrTwo,PC ; Print "two" farther ... C1D4: 17 07 6C LBSR PrintChars ; ... farther right C1D7: 17 04 36 LBSR PrintScores ; Print the player scores (both if two player) ; ; Show the life number indicators (3 bars -- the current life is active) C1DA: 8E 00 E4 LDX #$00E4 ; Utility object C1DD: 6F 02 CLR 2,X ; Y = 0 C1DF: C6 33 LDB #$33 ; 1st slot X ... C1E1: E7 84 STB ,X ; ... coordinate ; First slot (active if 3 lives) C1E3: 33 8D 0A 33 LEAU $CC1A,PC ; Life inidcator ACTIVE C1E7: D6 B5 LDB numLives ; Number of lives C1E9: C1 03 CMPB #$03 ; All 3? C1EB: 27 04 BEQ $C1F1 ; Yes ... 1st bar is CURRENT C1ED: 33 8D 0A 19 LEAU LifeIndicator,PC ; Life indicator INACTIVE C1F1: 17 05 69 LBSR Draw8x8 ; Draw the indicator C1F4: C6 3D LDB #$3D ; 2nd slot X ... C1F6: E7 84 STB ,X ; ... cooridinate ; Second slot (active if 2 lives) C1F8: 33 8D 0A 1E LEAU $CC1A,PC ; Life inidcator ACTIVE C1FC: D6 B5 LDB numLives ; Number of lives C1FE: C1 02 CMPB #$02 ; 2 remaining? C200: 27 04 BEQ $C206 ; Yes ... 2nd bar is CURRENT C202: 33 8D 0A 04 LEAU LifeIndicator,PC ; Life indicator INACTIVE C206: 17 05 54 LBSR Draw8x8 ; Draw the indicator C209: C6 47 LDB #$47 ; 3rd slot X ... C20B: E7 84 STB ,X ; ... coordinate ; Third slot (active if 1 life) C20D: 33 8D 0A 09 LEAU $CC1A,PC ; Life inidcator ACTIVE C211: D6 B5 LDB numLives ; Number of lives C213: C1 01 CMPB #$01 ; 1 remaining? C215: 27 04 BEQ $C21B ; Yes ... 3rd bar is CURRENT C217: 33 8D 09 EF LEAU LifeIndicator,PC ; Life indicator INACTIVE C21B: 17 05 3F LBSR Draw8x8 ; Draw the indicator ; ; Clear the player's line (all points to 64,64) C21E: 8E 00 D8 LDX #$00D8 ; Player-point object C221: 86 40 LDA #$40 ; Set X ... C223: A7 84 STA ,X ; ... to 64 ... C225: A7 02 STA 2,X ; ... and Y to 64 C227: 8E 02 00 LDX #$0200 ; Clear ... C22A: 5F CLRB ; ... the ... C22B: A7 80 STA ,X+ ; ... player ... C22D: 5A DECB ; ... line C22E: 26 FB BNE $C22B ; ... points ; ; Clear all game objects C230: 8E 01 60 LDX #$0160 ; Start of game objects C233: C6 A0 LDB #$A0 ; 160 / 8 = 20 possible objects C235: 6F 80 CLR ,X+ ; Clear ... C237: 5A DECB ; ... all ... C238: 26 FB BNE $C235 ; ... game objects C23A: 0F BD CLR collision ; Clear the collision flag ; ; Loop through one cycle of play -- over and over until done C23C: 17 00 16 LBSR OneCycle ; Move the player and the objects C23F: 0D BD TST collision ; Was there a collision? C241: 27 F9 BEQ $C23C ; No ... keep playing ; ; Dull the screen, play the tone, and return from the round C243: C6 F0 LDB #$F0 ; Dull screen ... C245: F7 FF 22 STB PIA1_DB ; ... color mode C248: 33 8D 0D 59 LEAU MusicEndOfLife,PC ; Play the ... C24C: 17 08 2F LBSR PlaySong ; ... end of life song C24F: C6 F8 LDB #$F8 ; Bright screen ... C251: F7 FF 22 STB PIA1_DB ; ... color mode C254: 39 RTS ; Done
One Cycle
This code is one pass through the game loop. It ends way down at C60F. There is a wait on VBLANK at the end of this loop. - Check for break and restart the program if pressed - Erase the tail of the player - Handle a small set game objects (not every object is processed every cycle) - Read sticks and move player's head - Check for looped objects (score and remove them) - Create a new object if it is time - Wait for the next VBLANK - Time down and remove any showing "loop score" - Flash the player word "one" or "two"
OneCycle: C255: 17 08 68 LBSR CheckForBreak ; Check for BREAK (reset if so) C258: 8E 02 00 LDX #$0200 ; Player's drawn coordinates C25B: D6 BE LDB endOfPlayer ; End of the list C25D: 3A ABX ; Offset to last point C25E: EC 84 LDD ,X ; X,Y of last point C260: 8E 00 DE LDX #$00DE ; Descriptor for erasing points C263: A7 84 STA ,X ; Set X ... C265: E7 02 STB 2,X ; ... and Y coordinate C267: 17 07 48 LBSR GetScreenAndShift ; Pointer and pixel number C26A: 17 07 29 LBSR ErasePixel ; Erase the tail of the player C26D: 0C D4 INC cycleCount ; Cycle count used to pace the objects
Move Game Objects
The game manages a list of 8-byte objects in memory at 0160. The array has 20 slots, but there is always a null slot (object type = 0) at the end to mark the end. Thus there can be only 19 objects on the screen at once.
Object structure (offset in the 8 bytes):
- 00 X coordinate
- 01 X residue (if used)
- 02 Y coordinate
- 03 Y residue (if used)
- 04 delta X (if used) and looped flag
- 05 delta Y (if used) and looped flag
- 06 object type (0 means end of list)
- 07 image number (if used) for flipping images
Every object has an object-type (1-9), and X coordinate, and a Y coordinate.
Animated objects us an "image number" value they can use to flip images, though some of the objects use the X coordinate odd/even instead.
Animated objects use a delta-X and delta-Y value to make their movements. The move-routine extends the X coordinate and Y coordinate to two-bytes each (the residue values in the structure). This allows for finer-grain movement speeds.
The delta-X and delta-Y fields are also used during the process of figuring out if an object has been looped or not. More on that with the looping-detection algorithm below.
C26F: 8E 01 60 LDX #$0160 ; List of objects ; ObjectLoop: C272: 6D 06 TST 6,X ; Object type 0 (end of list)? C274: 10 27 01 17 LBEQ $C38F ; Yes ... done with list C278: 30 08 LEAX 8,X ; Next slot C27A: 1F 10 TFR X,D ; 8 bytes per slot ... C27C: 54 LSRB ; ... get the ... C27D: 54 LSRB ; ... slot number ... C27E: 54 LSRB ; ... to B C27F: DB D4 ADDB cycleCount ; Add in cycle count C281: C4 07 ANDB #$07 ; Time for this slot to update? C283: 26 ED BNE ObjectLoop ; No ... skip this object C285: 30 18 LEAX -8,X ; Back up to start of this object C287: E6 06 LDB 6,X ; Object type C289: 5A DECB ; 1=APPLE (fixed position) C28A: 26 0A BNE $C296 ; No ... check other types C28C: 33 8D 08 6A LEAU ImageApple,PC ; Apple graphic C290: 17 04 CA LBSR Draw8x8 ; Draw apple C293: 16 00 F0 LBRA NextObject ; Next object C296: 5A DECB ; 2=CHERRY (fixed position) C297: 26 0A BNE $C2A3 ; No ... check other types C299: 33 8D 08 6D LEAU ImageCherry,PC ; Cherry graphic C29D: 17 04 BD LBSR Draw8x8 ; Draw cherry C2A0: 16 00 E3 LBRA NextObject ; Next object C2A3: 5A DECB ; 3=MAGNET (slow moving X/Y) C2A4: 26 17 BNE $C2BD ; No ... check other types C2A6: 33 8D 08 70 LEAU ImageMagnet,PC ; Erase current ... C2AA: 17 05 AE LBSR Erase8x8 ; ... magnet C2AD: CC 10 10 LDD #$1010 ; DeltaX,DeltaY = 16,16 C2B0: 17 07 4C LBSR FollowPlayer ; C2B3: 33 8D 08 63 LEAU ImageMagnet,PC ; Draw the ... C2B7: 17 04 A3 LBSR Draw8x8 ; ... magnet C2BA: 16 00 C9 LBRA NextObject ; Next object C2BD: 5A DECB ; 4=SKATE (moves along X only) C2BE: 26 24 BNE $C2E4 ; No ... check other types C2C0: 8D 13 BSR $C2D5 ; Get skate image C2C2: 17 05 96 LBSR Erase8x8 ; Erase the current skate C2C5: 6C 07 INC 7,X ; Next skate image C2C7: 86 10 LDA #$10 ; DeltaX,DeltaY = ... C2C9: 5F CLRB ; ... 16,0 C2CA: 17 07 32 LBSR FollowPlayer ; C2CD: 8D 06 BSR $C2D5 ; Get the skate image C2CF: 17 04 8B LBSR Draw8x8 ; Draw the skate C2D2: 16 00 B1 LBRA NextObject ; Next object ; C2D5: 33 8D 08 51 LEAU ImageSkate,PC ; Skate graphic 1 C2D9: E6 07 LDB 7,X ; Image number C2DB: C4 01 ANDB #$01 ; Either 0 or 1 C2DD: 26 04 BNE $C2E3 ; Not 1 ... use this graphic C2DF: 33 8D 08 57 LEAU $CB3A,PC ; Use skate graphic 2 C2E3: 39 RTS ; Done C2E4: 5A DECB ; 5=YOYO (moves up and down and leaves a string) C2E5: 26 3C BNE $C323 ; No ... check other types C2E7: 33 8D 08 9F LEAU $CB8A,PC ; Erase the current yoyo but ... C2EB: 17 05 6D LBSR Erase8x8 ; ... leave the string piece of the image C2EE: 4F CLRA ; Set deltaX ... C2EF: A7 04 STA 4,X ; ... to zero C2F1: C6 20 LDB #$20 ; Downward deltaY C2F3: 6D 07 TST 7,X ; Moving down? C2F5: 27 01 BEQ $C2F8 ; Yes ... keep this C2F7: 50 NEGB ; No ... moving UP. Negate it C2F8: E7 05 STB 5,X ; Store deltaY C2FA: 17 06 CB LBSR MoveObject ; C2FD: E6 02 LDB 2,X ; Y coordinate C2FF: C1 0C CMPB #$0C ; At the top-most allowed? C301: 24 04 BHS $C307 ; No ... keep moving in current direction C303: 6F 07 CLR 7,X ; Yes ... now moving down C305: C6 0C LDB #$0C ; Set to the top-most allowed C307: C1 42 CMPB #$42 ; At the bottom-most allowed? C309: 25 04 BLO $C30F ; No ... keep moving in current direction C30B: 6C 07 INC 7,X ; Yes ... now moving up C30D: C6 42 LDB #$42 ; Set to the bottom-most allowed C30F: E7 02 STB 2,X ; New Y coordinate C311: 33 8D 08 35 LEAU ImageYoYo,PC ; YoYo images C315: C4 03 ANDB #$03 ; 4 of them based on Y coordinate C317: 58 ASLB ; 16 ... C318: 58 ASLB ; ... bytes ... C319: 58 ASLB ; ... each ... C31A: 58 ASLB ; ... image C31B: 33 C5 LEAU B,U ; Point to current image C31D: 17 04 3D LBSR Draw8x8 ; C320: 16 00 63 LBRA NextObject ; Next object C323: 5A DECB ; 6=PEAR (fixed position) C324: 26 09 BNE $C32F ; No ... check other types C326: 33 8D 08 90 LEAU ImagePear,PC ; C32A: 17 04 30 LBSR Draw8x8 ; C32D: 20 57 BRA NextObject ; Next object C32F: 5A DECB ; 7=SPIDER (fast moving X/Y) C330: 26 21 BNE $C353 ; No ... check other types C332: 8D 10 BSR $C344 ; Get spider image C334: 17 05 24 LBSR Erase8x8 ; Erase current spider image C337: CC 30 30 LDD #$3030 ; DeltaX,DeltaY = 48,48 C33A: 17 06 C2 LBSR FollowPlayer ; Move towards player C33D: 8D 05 BSR $C344 ; Get spider image C33F: 17 04 1B LBSR Draw8x8 ; Draw the spider C342: 20 42 BRA NextObject ; Next object ; C344: 33 8D 08 82 LEAU ImageSpider,PC ; First spider image C348: E6 02 LDB 2,X ; Y coordinate C34A: C4 01 ANDB #$01 ; Is the Y coordinate odd? C34C: 26 04 BNE $C352 ; Yes ... use first image C34E: 33 8D 08 88 LEAU $CBDA,PC ; No ... use 2nd image C352: 39 RTS ; Done C353: 5A DECB ; 8=SKULL (fixed position) C354: 26 09 BNE $C35F ; No ... check other types C356: 33 8D 08 50 LEAU ImageSkull,PC ; C35A: 17 04 00 LBSR Draw8x8 ; C35D: 20 27 BRA NextObject ; Next object C35F: 5A DECB ; 9=X (very fast moving X/Y) C360: 26 24 BNE NextObject ; No. Anything but 0-9 ... skip. C362: 8D 13 BSR $C377 ; Get the current image C364: 17 04 F4 LBSR Erase8x8 ; Erase the current image C367: 6C 07 INC 7,X ; Next image index C369: CC 7F 7F LDD #$7F7F ; DeltaX,DeltaY = 127,127 ! Very fast! C36C: 17 06 90 LBSR FollowPlayer ; Move towards player C36F: 8D 06 BSR $C377 ; Get the image C371: 17 03 E9 LBSR Draw8x8 ; Draw the image C374: 16 00 0F LBRA NextObject ; Next object ; C377: 33 8D 08 6F LEAU ImageX,PC ; X picture small C37B: E6 07 LDB 7,X ; The image number C37D: C4 01 ANDB #$01 ; Is image number odd? C37F: 26 04 BNE $C385 ; Yes ... keep small picture C381: 33 8D 08 75 LEAU $CBFA,PC ; No ... use large picture C385: 39 RTS ; Done NextObject: C386: 6F 04 CLR 4,X ; Clear any ... C388: 6F 05 CLR 5,X ; ... deltas (used as flags later) C38A: 30 08 LEAX 8,X ; Next object C38C: 16 FE E3 LBRA ObjectLoop ; continue with next
Read the Player's Input
Any "loop score" that is showing is erased before the player is drawn. Collision detection is noted as the player is drawn. Then any "loop score" is immediately drawn back.
Joystick axises are read as 6-bit values from 0 (left/up) to 63 (right/down). The code subtracts 32 to make 6-bit signed values for the delta-X and delta-Y.
; Read the player's input C38F: 9F D2 STX nextFreeObj ; C391: AD 9F A0 0A JSR [JOYIN] ; JOYIN reads all 4 joysticks (15A,15B,15C,15D) C395: 8E 00 D8 LDX #$00D8 ; Object for drawing player point C398: 10 8E 01 5A LDY #$015A ; Memory for analog inputs C39C: D6 B6 LDB player ; Player number C39E: 58 ASLB ; 2 axis per joystick C39F: 31 A5 LEAY B,Y ; Point to 15A, 15B (player 0) or 15C, 15D (player 1) C3A1: E6 A4 LDB ,Y ; Get the X stick value C3A3: A6 A4 LDA ,Y ; Add in ... C3A5: 9B D7 ADDA random ; ... some ... C3A7: 97 D7 STA random ; ... randomness to RNG C3A9: C0 20 SUBB #$20 ; 0 to 64 now -32 to 32 C3AB: E7 04 STB 4,X ; Hold as delta X C3AD: E6 21 LDB 1,Y ; Next axis C3AF: C0 20 SUBB #$20 ; 0 to 64 now -32 to 32 C3B1: E7 05 STB 5,X ; Hold as delta Y C3B3: 17 06 12 LBSR MoveObject ; Move ... C3B6: 17 03 66 LBSR EraseLoopScore ; ... player's dot ; ; Draw the new player head C3B9: 8E 00 D8 LDX #$00D8 ; Player point structure C3BC: 17 05 A0 LBSR SetPixel ; Draw the new player dot C3BF: D7 BF STB origPixel ; Hold the original pixel (for collision detection) C3C1: 17 03 4F LBSR DrawLoopScore ; Redraw the loop score (after we drew the head and checked collision) ; ; Check for a loop C3C4: 0F C3 CLR nontouch ; So far, no non-touching point C3C6: D6 BE LDB endOfPlayer ; End of the player ... C3C8: D7 C0 STB objCounter ; ... line (ring buffer) ; C3CA: D6 C0 LDB objCounter ; Move up ... C3CC: C0 02 SUBB #$02 ; ... one point (this wraps around from FF) C3CE: D7 C0 STB objCounter ; Hold the new pointer C3D0: D1 BE CMPB endOfPlayer ; Caught up to head? C3D2: 10 27 01 24 LBEQ $C4FA ; Yes ... we are done C3D6: 8E 02 00 LDX #$0200 ; Player's points C3D9: 3A ABX ; Offset into the points C3DA: EC 84 LDD ,X ; Get X,Y of point C3DC: 8E 00 D8 LDX #$00D8 ; Player's X,Y C3DF: A0 84 SUBA ,X ; This point ... C3E1: 4C INCA ; ... X next to the ... C3E2: 81 02 CMPA #$02 ; ... start X? C3E4: 22 07 BHI $C3ED ; No ... skip C3E6: E0 02 SUBB 2,X ; This point ... C3E8: 5C INCB ; ... Y next to the ... C3E9: C1 02 CMPB #$02 ; Start Y? C3EB: 23 04 BLS $C3F1 ; Yes ... we need to check for looped objects C3ED: 0C C3 INC nontouch ; C3EF: 20 D9 BRA $C3CA ; Keep looking for a crossing ; C3F1: 10 83 01 01 CMPD #$0101 ; Did we cross ourselves (as opposed to just touching next to the head) C3F5: 26 02 BNE $C3F9 ; No ... keep the point under the player C3F7: 0F BF CLR origPixel ; Clear the pixel under the player (no collision) C3F9: 0D C3 TST nontouch ; Were there any points that didn't touch the head? C3FB: 27 CD BEQ $C3CA ; No ... we are on top of ourselves ... keep looking for a crossing C3FD: 0F BF CLR origPixel ; No collision detection ; C3FF: D6 C0 LDB objCounter ; Note where we ... C401: D7 C1 STB loopStart ; ... formed a loop C403: D6 BE LDB endOfPlayer ; Reset ... C405: D7 C0 STB objCounter ; ... the end pointer ; C407: D6 C0 LDB objCounter ; Move up ... C409: C0 02 SUBB #$02 ; a point C40B: D7 C0 STB objCounter ; New pointer C40D: 8E 02 00 LDX #$0200 ; Player line points C410: 3A ABX ; Get the ... C411: EC 84 LDD ,X ; ... X,Y coordinates C413: C0 03 SUBB #$03 ; Translate to top of objects (compare player point to center of object) C415: D7 C2 STB transY ; Hold the Y C417: 80 03 SUBA #$03 ; Translate the left side of objects ... X in A C419: 8E 01 60 LDX #$0160 ; Start of objects
Looped Object Detection
We look at all points in the player's loop. For each point, we run the list of objects. If the Y coordinate of the player point matches the object's center Y coordinate (or one beyond) then we note the object as having a point on either the left or right side by comparing the X coordinates. These notes are kept in the object structure at OBJ[4] for left side or OBJ[5] for right side.
After we have run all points, we look at the notes. If an object has a point noted on the left AND on the right side, we consider it looped.
Most of the time, this is a good (and fast) check. But you can "loop" and object by making a "U" around it either up or down without actually going around it. In fact, the sides of the U can be half the height of the object.
For instance, this object "O" is considered looped by the player line "*":
******************
* *
* ************** *
* * * *
* * OOOOOOOO * *
* * OOOOOOOO * *
* * OOOOOOOO * *
*** OOOOOOOO ***
OOOOOOOO
OOOOOOOO
OOOOOOOO
OOOOOOOO
C41C: 6D 06 TST 6,X ; Reached the end of the list? C41E: 27 15 BEQ $C435 ; yes ... done C420: D6 C2 LDB transY ; The Y coordinate C422: E0 02 SUBB 2,X ; Compare Y coordinates C424: 54 LSRB ; (Also match the next Y coordinate) C425: 26 0A BNE $C431 ; This Y coordinate is not the center of the object .. skip C427: A1 84 CMPA ,X ; The X coordinate is ... C429: 22 04 BHI $C42F ; ... above. Mark that. C42B: 6C 04 INC 4,X ; Mark the X coordinate is below C42D: 20 02 BRA $C431 ; Check other points C42F: 6C 05 INC 5,X ; There was a Y coordinate close C431: 30 08 LEAX 8,X ; Check all ... C433: 20 E7 BRA $C41C ; ... objects ; C435: D6 C0 LDB objCounter ; Check ... C437: D1 C1 CMPB loopStart ; ... all points ... C439: 26 CC BNE $C407 ; ... in the loop ; C43B: 8E 01 60 LDX #$0160 ; Start of objects C43E: 0F C4 CLR numLooped ; Number of objects looped C440: 0F C8 CLR loopScoreTmp ; Sum of ... C442: 0F C9 CLR loopScoreTmp+1 ; ... looped objects score ; C444: E6 06 LDB 6,X ; End of the object list? C446: 27 5D BEQ $C4A5 ; Yes ... done C448: 6D 04 TST 4,X ; Close-Y points on the left? C44A: 27 55 BEQ $C4A1 ; No ... wasn't looped C44C: 6D 05 TST 5,X ; And close-Y points on the right? C44E: 27 51 BEQ $C4A1 ; No ... wasn't looped C450: C1 08 CMPB #$08 ; This object a skull? C452: 27 4D BEQ $C4A1 ; Yes ... it doesn't count ... next object C454: 0C C4 INC numLooped ; number of objects looped C456: 0C D0 INC totalLoops ; C458: 0A CE DEC liveObjCnt ; ; ; Score the looped object C45A: 33 8D 0B 4B LEAU ScoreTable,PC ; The table of object scores C45E: E6 C5 LDB B,U ; Get the score for this object C460: 1D SEX ; No score is greater than 127 ... this is a quick way to clear A C461: D3 C8 ADDD loopScoreTmp ; Add the score ... C463: DD C8 STD loopScoreTmp ; ... to the accumulated loop score C465: CE 00 EA LDU #$00EA ; Descriptor for erasing C468: E6 84 LDB ,X ; Copy ... C46A: E7 C4 STB ,U ; ... X coordinate C46C: E6 02 LDB 2,X ; Copy ... C46E: E7 42 STB 2,U ; ... Y coordinate C470: 33 8D 07 B7 LEAU GenericEraser,PC ; Erase the ... C474: 17 03 E4 LBSR Erase8x8 ; ... object C477: E6 06 LDB 6,X ; Is this ... C479: C1 05 CMPB #$05 ; ... a yoyo? C47B: 26 11 BNE $C48E ; No ... skip the string C47D: 33 8D 07 19 LEAU StringEraser,PC ; Line erase graphic C481: 17 03 D7 LBSR Erase8x8 ; Erase the string C484: E6 02 LDB 2,X ; Move ... C486: C0 04 SUBB #$04 ; ... up by ... C488: E7 02 STB 2,X ; ... 4 pixels C48A: C1 03 CMPB #$03 ; At the top of the screen? C48C: 2E F3 BGT $C481 ; No ... keep erasing possible string C48E: 1F 13 TFR X,U ; For memory copy C490: C6 08 LDB #$08 ; 8 bytes per object C492: DF D2 STU nextFreeObj ; end of the object list (where we add new objects) C494: A6 48 LDA 8,U ; Close ... C496: A7 C0 STA ,U+ ; ... up ... C498: 5A DECB ; ... list ... C499: 26 F9 BNE $C494 ; ... over ... C49B: 6D 46 TST 6,U ; ... removed ... C49D: 26 F1 BNE $C490 ; ... object C49F: 20 A3 BRA $C444 ; Next object ; C4A1: 30 08 LEAX 8,X ; Next object C4A3: 20 9F BRA $C444 ; Continue checking C4A5: 0D C4 TST numLooped ; Were any objects looped? C4A7: 27 51 BEQ $C4FA ; No ... skip score update C4A9: 17 02 73 LBSR EraseLoopScore ; Erase any loop score being shown C4AC: 4F CLRA ; Score for all ... C4AD: 5F CLRB ; Looped ... C4AE: D3 C8 ADDD loopScoreTmp ; Sum of looped objects score C4B0: 0A C4 DEC numLooped ; Multiply score of summed by ... C4B2: 26 FA BNE $C4AE ; ... number of objects looped C4B4: DD CA STD loopScoreShown ; The value of the loop score to show C4B6: 0D B6 TST player ; Player 0 or 1 C4B8: 26 06 BNE $C4C0 ; ... player 1 C4BA: D3 B7 ADDD p1Score ; Player 1 score C4BC: DD B7 STD p1Score ; Update player 1 score C4BE: 20 04 BRA $C4C4 ; Continue C4C0: D3 B9 ADDD p2Score ; Player 2 score C4C2: DD B9 STD p2Score ; Update player 2 score C4C4: C6 3C LDB #$3C ; Counter for showing ... C4C6: D7 C6 STB loopScoreCnt ; ... loop score C4C8: 8E 00 EA LDX #$00EA ; Current game object C4CB: E6 84 LDB ,X ; X coordinate C4CD: C1 60 CMPB #$60 ; Too far to the right to print score? C4CF: 2F 02 BLE $C4D3 ; No ... keep it C4D1: C6 60 LDB #$60 ; Keep loop score on the screen C4D3: E7 84 STB ,X ; Constrained X coordinate C4D5: 17 04 DA LBSR GetScreenAndShift ; Store the screen ... C4D8: DF CC STU loopScoreLoc ; ... location of the loop score C4DA: 0C C7 INC hasLoopScore ; We now have a loop score to show C4DC: 17 01 31 LBSR PrintScores ; Print the scores (both if 2 player) ; ; Make popping sound after scoring object C4DF: 7F FF 20 CLR PIA1_DA ; DAC to zero C4E2: BD A9 76 JSR $A976 ; Enable the sound C4E5: C6 80 LDB #$80 ; Outer loop C4E7: 1F 98 TFR B,A ; Outter to inner C4E9: 4A DECA ; Slight ... C4EA: 26 FD BNE $C4E9 ; ... delay C4EC: F7 FF 20 STB PIA1_DA ; Store samples C4EF: 1F 98 TFR B,A ; Another ... C4F1: 4A DECA ; ... slight ... C4F2: 26 FD BNE $C4F1 ; ... delay C4F4: 7F FF 20 CLR PIA1_DA ; DAC to 0 C4F7: 5A DECB ; All loops made? C4F8: 26 ED BNE $C4E7 ; No ... continue popping sound
Update the Player's Line
The new "head" coordinate overwrites the tail coordinate, and the dividing line moves around the ring.
C4FA: 8E 02 00 LDX #$0200 ; The player's line points C4FD: D6 BE LDB endOfPlayer ; the end of the player line C4FF: 3A ABX ; The tail and head separator C500: CE 00 D8 LDU #$00D8 ; Player's head C503: A6 C4 LDA ,U ; Player's head ... C505: E6 42 LDB 2,U ; ... X and Y C507: ED 84 STD ,X ; Add it to the start of the list (will be start after we increment below) ; C509: D6 BF LDB origPixel ; The pixel the player over-drew C50B: DB BD ADDB collision ; Mark ... C50D: D7 BD STB collision ; ... collision C50F: 0C BE INC endOfPlayer ; Next point ... C511: 0C BE INC endOfPlayer ; ... slot in player line
Make new Game Object
We only allow 19 game object on the screen at once. The type of the object made depends on the player's score and the number of completed loops the player has made. Higher values result in more advanced objects.
When the code tries to make a new skull, it looks to see if there are already 10 skulls on the screen. If there are, the new object becomes the fast moving "X" shape instead.
C513: 0C D1 INC nextObjTime ; Time to make a new object? C515: 10 26 00 B3 LBNE $C5CC ; No ... skip making one C519: D6 CE LDB liveObjCnt ; Do we already have ... C51B: C1 13 CMPB #$13 ; ... 19 objects? C51D: 10 2C 00 AB LBGE $C5CC ; Yes ... skip making one C521: 0C CE INC liveObjCnt ; Bump the object count C523: 33 8D 0A 7A LEAU $CFA1,PC ; Make the popping sound ... C527: 17 05 54 LBSR PlaySong ; ... of a new object appearing ; ; We are making a new object now, but we'll make the timer until the next one. ; Next object's appearence is based on the total number of loops made so far and the player's ; score. The more loops and the higher the score, the sooner the next object can appear. C52A: 96 D0 LDA totalLoops ; Total number of loops made C52C: 48 ASLA ; Times ... C52D: 48 ASLA ; ... 4 C52E: 8E 00 B7 LDX #$00B7 ; Player 1 score C531: D6 B6 LDB player ; Which player is playing? C533: 58 ASLB ; Point to current player score C534: AB 85 ADDA B,X ; Add in the player's score upper byte C536: 94 D7 ANDA random ; Some randomness C538: 97 D1 STA nextObjTime ; Timer for next object to appear ; ; The type of the next object is random but based on the player's score. The higher the score, the ; more advanced the object can be. ; (SCORE[0]+4) * random(256) / 256 ; For a score of 0: 4*255/256 = 0,1,2,3 (apple, cherry, magnet, skate) ; Upper digit of 4 is 4*256 = 1024. Add the extra zero (all scores have it): 10,000 is where skulls start. ; TODO break them all down ; For a score of (4+4)*255/256 = 0,1,2,3,4,5,6,7 (everything ... skulls begin) C53A: A6 85 LDA B,X ; Upper byte of score C53C: 8B 04 ADDA #$04 ; Add 4 (even with no score you can get an object) C53E: D6 D7 LDB random ; Multiply ... C540: 3D MUL ; ... by random number 0 to 255 C541: 84 07 ANDA #$07 ; Divide by 256 and random object type ... C543: 4C INCA ; ... from 1 to 8 C544: 81 08 CMPA #$08 ; Is this a skull? C546: 26 09 BNE $C551 ; No ... keep whatever it is
The Unexpected
This is the code that creates the fast-moving "X" after 10 skulls.
C548: 0C CF INC skullCount ; Bump the skull count C54A: D6 CF LDB skullCount ; Do we have ... C54C: C1 0A CMPB #$0A ; ... 10 skulls on the screen? C54E: 23 01 BLS $C551 ; No ... this is a new skull C550: 4C INCA ; Yes ... promote this to a moving "X" C551: 9E D2 LDX nextFreeObj ; Next object slot C553: A7 06 STA 6,X ; New object's type C555: 6F 07 CLR 7,X ; Any image flipping starts at 0 ; ; Pick a candidate X,Y coordinate (we'll check it later) C557: 96 D7 LDA random ; Mix ... C559: 1F 89 TFR A,B ; ... up ... C55B: 54 LSRB ; ... the ... C55C: 46 RORA ; ... C55D: 54 LSRB ; ... C55E: 46 RORA ; ... C55F: 97 D7 STA random ; ... random a bit C561: 54 LSRB ; Mix ... C562: 46 RORA ; ... C563: 54 LSRB ; ... C564: 46 RORA ; ... even more C565: C6 44 LDB #$44 ; Y coordinate = ... C567: 3D MUL ; ... random(68) ... C568: 8B 08 ADDA #$08 ; ... + 8 C56A: A7 02 STA 2,X ; New random Y coordinate C56C: 96 D7 LDA random ; Random value C56E: C6 60 LDB #$60 ; X coordinate = ... C570: 3D MUL ; ... random(96) ; TODO simulate this algorithm and see what's going on exactly C571: 84 FC ANDA #$FC ; Drop lower 2 bits C573: 8B 0C ADDA #$0C ; Now between 12 and 119 C575: 8B 04 ADDA #$04 ; Move right 4 bits C577: 81 6C CMPA #$6C ; Too close to the right side (X=108)? C579: 24 FA BHS $C575 ; Yes ... keep moving right 4 (and wrap) C57B: 81 10 CMPA #$10 ; Too close to the left sice (X=16)? C57D: 23 F6 BLS $C575 ; Yes ... keep moving right 4 (and wrap) C57F: A7 84 STA ,X ; X coordinate ; ; Don't drop a new object near the player C581: E6 02 LDB 2,X ; Y coordinate C583: CE 00 D8 LDU #$00D8 ; Player's X,y C586: E0 42 SUBB 2,U ; Are we far ... C588: CB 14 ADDB #$14 ; ... enough from ... C58A: C1 28 CMPB #$28 ; ... the player? C58C: 24 0C BHS $C59A ; Yes ... keep this location C58E: A0 C4 SUBA ,U ; No ... compare X too C590: 8B 14 ADDA #$14 ; Are we far ... C592: 81 28 CMPA #$28 ; ... enough from the player? C594: 24 04 BHS $C59A ; Yes ... keep this location C596: A6 84 LDA ,X ; No ... go back for ... C598: 20 DB BRA $C575 ; ... another random X coordinate ; ; Try not to drop similar objects near each other C59A: 1F 13 TFR X,U ; Is this the ... C59C: 11 83 01 60 CMPU #$0160 ; ... first slot? C5A0: 27 2A BEQ $C5CC ; Yes ... good to go C5A2: 33 58 LEAU -8,U ; Is one of this ... C5A4: E6 46 LDB 6,U ; ... new object ... C5A6: E1 06 CMPB 6,X ; ... alread on the screen? C5A8: 26 F2 BNE $C59C ; Keep checking C5AA: E6 84 LDB ,X ; Compare ... C5AC: E0 C4 SUBB ,U ; ... X coordinate C5AE: CB 08 ADDB #$08 ; +8 C5B0: C1 10 CMPB #$10 ; Are these close in X? C5B2: 22 E8 BHI $C59C ; No ... keep checking C5B4: E6 02 LDB 2,X ; Compare ... C5B6: E0 42 SUBB 2,U ; ... Y coordinate C5B8: CB 08 ADDB #$08 ; +8 C5BA: C1 10 CMPB #$10 ; Are these close in Y? C5BC: 22 DE BHI $C59C ; No ... keep checking C5BE: E6 02 LDB 2,X ; Y coordinate C5C0: CB 15 ADDB #$15 ; Move Y coordinate down 21 C5C2: C1 4C CMPB #$4C ; too close to the bottom? C5C4: 2D 02 BLT $C5C8 ; No keep it C5C6: C0 44 SUBB #$44 ; Yes ... back it up to the top C5C8: E7 02 STB 2,X ; New Y coordinate C5CA: 20 CA BRA $C596 ; Go all the way back for another random X coordinate ; ; Sync up to VBLANK for timing and tearing C5CC: 17 05 20 LBSR WaitVBlank ; Sync the gameloop to VBLANK ; ; Time down and remove loop score indicator C5CF: 0D C7 TST hasLoopScore ; Is there a loop score showing? C5D1: 27 09 BEQ $C5DC ; No ... skip timing it out C5D3: 0A C6 DEC loopScoreCnt ; Time to erase it? C5D5: 26 05 BNE $C5DC ; No ... leave it alone C5D7: 17 01 45 LBSR EraseLoopScore ; Erase the loop score C5DA: 0F C7 CLR hasLoopScore ; No longer showing the loop score C5DC: 0A D5 DEC flashCount ; Time to flash the player word? ; ; Flash the player's word on and off with a counter C5DE: 26 2F BNE $C60F ; No ... skip it C5E0: C6 28 LDB #$28 ; Reload the ... C5E2: D7 D5 STB flashCount ; ... player word flash counter C5E4: C6 58 LDB #$58 ; Y coordinate of player word C5E6: 0D B6 TST player ; Player one? C5E8: 26 12 BNE $C5FC ; No ... go to player one C5EA: 86 18 LDA #$18 ; X coordinate of player "one" C5EC: 03 D6 COM flashType ; Value was zero? C5EE: 26 06 BNE $C5F6 ; Yes ... erase the word C5F0: 33 8D 06 89 LEAU StrOne,PC ; No ... print the word C5F4: 20 16 BRA $C60C ; Go print and out C5F6: 33 8D 06 31 LEAU GenericEraser,PC ; Erase the word C5FA: 20 10 BRA $C60C ; Go erase and out ; C5FC: 86 52 LDA #$52 ; X coordinate for "two" C5FE: 03 D6 COM flashType ; Value was zero? C600: 26 06 BNE $C608 ; Yes ... erase the word C602: 33 8D 06 98 LEAU StrTwo,PC ; No ... print the word C606: 20 04 BRA $C60C ; Go print and out C608: 33 8D 06 1F LEAU GenericEraser,PC ; Erase graphics C60C: 17 03 34 LBSR PrintChars ; Draw whatever graphics C60F: 39 RTS ; Done
Print Scores
Number are drawn with 4x5 pixel patterns (see the images below). The right most column is always blank for spacing.
Both scores are printed at the same time (or just one for 1-player game).
PrintScores: C610: C6 FF LDB #$FF ; White background chars ... C612: D7 C5 STB digitColor ; ... for score digits C614: DC B7 LDD p1Score ; Player one score C616: CE 0F 2B LDU #$0F2B ; Location of player one score on screen C619: 17 00 0F LBSR DrawNumber ; Print player one score C61C: 0D B4 TST numPlayers ; Is there a second player? C61E: 27 08 BEQ $C628 ; No ... skip player two score C620: DC B9 LDD p2Score ; Player two score C622: CE 0F 3A LDU #$0F3A ; Location of player two score on screen C625: 17 00 03 LBSR DrawNumber ; Print the player two score C628: 0F C5 CLR digitColor ; Default back to black background chars C62A: 39 RTS ; Done
Draw Number
This code breaks a 2-byte word into 5 printed digits. Much of the work is brute-force. Numbers are always drawn with a trailing 0; every value is shown multiplied by 10. Space invaders did this too to make the scores look bigger.
The maximum printed number is thus 655360 with the trailing zero.
The code drops leading 0s at it prints. The code does not preserve the screen bits around the digits.
DrawNumber: ; Numbers are kept in words ... max value 65_536. Max 5 digits. ; An extra "0" is always added to the end of the number (multiply by 10) C62B: 10 83 27 10 CMPD #$2710 ; Decimal 10_000 C62F: 24 14 BHS $C645 ; Handle digits C631: 10 83 03 E8 CMPD #$03E8 ; Decimal 1_000 C635: 24 13 BHS $C64A ; Handle 4 digits C637: 10 83 00 64 CMPD #$0064 ; Decimal 100 C63B: 24 12 BHS $C64F ; Handle 3 digits C63D: 10 83 00 0A CMPD #$000A ; Decimal 10 C641: 24 11 BHS $C654 ; Handle 2 digit C643: 20 14 BRA $C659 ; Just one digit ; C645: 8E 27 10 LDX #$2710 ; Base amount 10000 C648: 8D 19 BSR $C663 ; Draw digit picture C64A: 8E 03 E8 LDX #$03E8 ; Base amount 1000 C64D: 8D 14 BSR $C663 ; Draw digit picture C64F: 8E 00 64 LDX #$0064 ; Base amount 100 C652: 8D 0F BSR $C663 ; Draw digit picture C654: 8E 00 0A LDX #$000A ; Base amount 10 C657: 8D 0A BSR $C663 ; Draw digit picture C659: 8E 00 01 LDX #$0001 ; Base amount 1 C65C: 8D 05 BSR $C663 ; Draw digit picture C65E: 4F CLRA ; Add a ... C65F: 5F CLRB ; ... zero to everything C660: 8D 01 BSR $C663 ; Print 0 C662: 39 RTS ; Done ; C663: 34 10 PSHS X ; Hold the value C665: 30 8D 00 78 LEAX Digit0,PC ; Graphics for "0" C669: A3 E4 SUBD ,S ; Subtract off base amount C66B: 25 46 BLO $C6B3 ; This is the digit C66D: 30 8D 00 75 LEAX Digit1,PC ; Graphics for "1" C671: A3 E4 SUBD ,S ; Subtract off base amount C673: 25 3E BLO $C6B3 ; This is the digit C675: 30 8D 00 72 LEAX Digit2,PC ; Graphics for "2" C679: A3 E4 SUBD ,S ; Subtract off base amount C67B: 25 36 BLO $C6B3 ; This is the digit C67D: 30 8D 00 6F LEAX Digit3,PC ; Graphics for "3" C681: A3 E4 SUBD ,S ; Subtract off base amount C683: 25 2E BLO $C6B3 ; This is the digit C685: 30 8D 00 6C LEAX Digit4,PC ; Graphics for "4" C689: A3 E4 SUBD ,S ; Subtract off base amount C68B: 25 26 BLO $C6B3 ; This is the digit C68D: 30 8D 00 69 LEAX Digit5,PC ; Graphics for "5" C691: A3 E4 SUBD ,S ; Subtract off base amount C693: 25 1E BLO $C6B3 ; This is the digit C695: 30 8D 00 66 LEAX Digit6,PC ; Graphics for "6" C699: A3 E4 SUBD ,S ; Subtract off base amount C69B: 25 16 BLO $C6B3 ; This is the digit C69D: 30 8D 00 63 LEAX Digit7,PC ; Graphics for "7" C6A1: A3 E4 SUBD ,S ; Subtract off base amount C6A3: 25 0E BLO $C6B3 ; This is the digit C6A5: 30 8D 00 60 LEAX Digit8,PC ; Graphics for "8" C6A9: A3 E4 SUBD ,S ; Subtract off base amount C6AB: 25 06 BLO $C6B3 ; This is the digit C6AD: 30 8D 00 5D LEAX Digit9,PC ; Graphics for "9" C6B1: A3 E4 SUBD ,S ; Subtract off base amount C6B3: E3 E4 ADDD ,S ; Add one base amount back (we overshot above) C6B5: 34 06 PSHS B,A ; Hold the value C6B7: E6 84 LDB ,X ; Get first row data C6B9: 54 LSRB ; Everything drawn in color "01" (not sure why it wasn't defined that way to begin with) C6BA: D8 C5 EORB digitColor ; Flip the color if needed C6BC: E7 C0 STB ,U+ ; Store to screen C6BE: E6 01 LDB 1,X ; Repeat ... C6C0: 54 LSRB ; ... with ... C6C1: D8 C5 EORB digitColor ; ... next ... C6C3: E7 C8 1F STB $1F,U ; ... row C6C6: E6 02 LDB 2,X ; Repeat ... C6C8: 54 LSRB ; ... with ... C6C9: D8 C5 EORB digitColor ; ... next ... C6CB: E7 C8 3F STB $3F,U ; ... row C6CE: E6 03 LDB 3,X ; Repeat ... C6D0: 54 LSRB ; ... with ... C6D1: D8 C5 EORB digitColor ; ... next ... C6D3: E7 C8 5F STB $5F,U ; ... row C6D6: E6 04 LDB 4,X ; Repeat ... C6D8: 54 LSRB ; ... with ... C6D9: D8 C5 EORB digitColor ; ... next ... C6DB: E7 C8 7F STB $7F,U ; ... row C6DE: 35 16 PULS A,B,X ; Restore C6E0: 39 RTS ; Done
Digit Graphics
Digit0: ; ..#..... ; #...#... ; #...#... ; #...#... ; ..#..... C6E1: 20 88 88 88 20 Digit1: ; ..#..... ; #.#..... ; ..#..... ; ..#..... ; #.#.#... C6E6: 20 A0 20 20 A8 Digit2: ; ..#..... ; #...#... ; ....#... ; ..#..... ; #.#.#... C6EB: 20 88 08 20 A8 Digit3: ; #.#.#... ; ....#... ; ..#.#... ; ....#... ; #.#.#... C6F0: A8 08 28 08 A8 Digit4: ; #....... ; #...#... ; #...#... ; #.#.#... ; ....#... C6F5: 80 88 88 A8 08 Digit5: ; #.#.#... ; #....... ; ..#..... ; ....#... ; #.#..... C6FA: A8 80 20 08 A0 Digit6: ; #.#.#... ; #....... ; #.#.#... ; #...#... ; #.#.#... C6FF: A8 80 A8 88 A8 Digit7: ; #.#.#... ; ....#... ; ....#... ; ..#..... ; ..#..... C704: A8 08 08 20 20 Digit8: ; #.#.#... ; #...#... ; #.#.#... ; #...#... ; #.#.#... C709: A8 88 A8 88 A8 Digit9: ; ..#..... ; #...#... ; ..#.#... ; ....#... ; #.#..... C70E: 20 88 28 08 A0
Draw and Erase the Loop Score
This code checks to see if there is a loop-score showing before taking action.
DrawLoopScore: ; If there is a loop score, draw it C713: 0D C7 TST hasLoopScore ; Is there a value? C715: 27 07 BEQ $C71E ; No ... skip drawing it C717: DE CC LDU loopScoreLoc ; Screen coordinate C719: DC CA LDD loopScoreShown ; Value C71B: 17 FF 0D LBSR DrawNumber ; Draw number C71E: 39 RTS ; Done EraseLoopScore: C71F: 0D C7 TST hasLoopScore ; Is there a value? C721: 27 2A BEQ $C74D ; No ... skip erasing it C723: DE CC LDU loopScoreLoc ; Screen coordinate C725: DC CA LDD loopScoreShown ; Value C727: 10 83 27 10 CMPD #$2710 ; Decimal 10_000 C72B: 24 14 BHS $C741 ; Erase 6 digits C72D: 10 83 03 E8 CMPD #$03E8 ; Decimal 1_000 C731: 24 10 BHS $C743 ; Erase 5 digits C733: 10 83 00 64 CMPD #$0064 ; Decimal 100 C737: 24 0C BHS $C745 ; Erase 4 digits C739: 10 83 00 0A CMPD #$000A ; Decimal 10 C73D: 24 08 BHS $C747 ; Erase 3 digits C73F: 20 08 BRA $C749 ; Erase 2 digits
Erase a Number
This is very similar brute-force logic as drawing a number, except here the screen area is erased.
Note this is only ever called when erasing the loop score. The only other numbers on the screen are the scores, and they are just overwritten without being erased first.
; Erase number of digits C741: 8D 0B BSR EraseDigit ; Erase 1 digit and advance C743: 8D 09 BSR EraseDigit ; Erase 1 digit and advance C745: 8D 07 BSR EraseDigit ; Erase 1 digit and advance C747: 8D 05 BSR EraseDigit ; Erase 1 digit and advance C749: 8D 03 BSR EraseDigit ; Erase 1 digit and advance C74B: 8D 01 BSR EraseDigit ; Erase 1 digit and advance C74D: 39 RTS ; Done EraseDigit: ; Erase the digit and advance U to next digit start C74E: 6F C0 CLR ,U+ ; Erase 1st line and advance U C750: 6F C8 1F CLR $1F,U ; Erase 2nd line C753: 6F C8 3F CLR $3F,U ; Erase 3rd line C756: 6F C8 5F CLR $5F,U ; Erase 4th line C759: 6F C8 7F CLR $7F,U ; Erase 5th line C75C: 39 RTS ; Done
Draw and Erase an 8x8 Pixel Object
This code ORs an 8x8 pixel object onto the screen. A pixel value of 00 in the object is considered transparent, and the existing screen pixels are left alone.
There is a lot of screen-math and shifting here since there are 4 pixels per byte.
Draw8x8: ; X = object pointer (has X,Y coordinate) ; U = pointer to data (8x8 pixels = 16 bytes) C75D: C6 08 LDB #$08 ; 8 Rows C75F: 34 54 PSHS U,X,B ; Hold these C761: 17 02 4E LBSR GetScreenAndShift ; Get pointer to screen memory C764: 10 8E 03 80 LDY #$0380 ; Mask table C768: AE 63 LDX 3,S ; Incoming U (data pointer) to X C76A: 5D TSTB ; 0 means ... C76B: 10 27 00 CA LBEQ $C839 ; ... draw with no shift C76F: 5A DECB ; 1 means ... C770: 10 27 00 88 LBEQ $C7FC ; ... one pixel shift right C774: 5A DECB ; 2 means ... C775: 10 27 00 3E LBEQ $C7B7 ; ... two pixel shift right ; ; One pixel shift left (three pixel shift right) C779: E6 80 LDB ,X+ ; First byte of pixel data C77B: 4F CLRA ; Make it a word with leading 0s C77C: 58 ASLB ; Shift ... C77D: 49 ROLA ; ... left ... C77E: 58 ASLB ; ... one ... C77F: 49 ROLA ; ... pixel C780: 34 06 PSHS B,A ; Hold this C782: E6 80 LDB ,X+ ; Second byte of pixel data C784: 4F CLRA ; Make it a word with leading 0s C785: 58 ASLB ; Shift ... C786: 49 ROLA ; ... left ... C787: 58 ASLB ; ... one ... C788: 49 ROLA ; ... pixel C789: AB 61 ADDA 1,S ; Combine pixels ... C78B: A7 61 STA 1,S ; ... in middle byte C78D: 34 04 PSHS B ; Third byte C78F: A6 A5 LDA B,Y ; Mask ... C791: A4 42 ANDA 2,U ; ... screen ... C793: AB E4 ADDA ,S ; ... add pixels ... C795: A7 42 STA 2,U ; ... to screen C797: E6 62 LDB 2,S ; 2nd byte C799: A6 A5 LDA B,Y ; Mask ... C79B: A4 41 ANDA 1,U ; ... screen ... C79D: AB 62 ADDA 2,S ; ... add pixels ... C79F: A7 41 STA 1,U ; ... to screen C7A1: E6 61 LDB 1,S ; First byte C7A3: A6 A5 LDA B,Y ; Mask ... C7A5: A4 C4 ANDA ,U ; ... screen ... C7A7: AB 61 ADDA 1,S ; ... add pixels ... C7A9: A7 C4 STA ,U ; ... to screen C7AB: 32 63 LEAS 3,S ; Pull the 3-byte temporary C7AD: 33 C8 20 LEAU $20,U ; Next row C7B0: 6A E4 DEC ,S ; All rows done? C7B2: 26 C5 BNE $C779 ; No ... keep going C7B4: 16 00 A1 LBRA $C858 ; Yes ... done ; ; Two pixel shift right C7B7: E6 80 LDB ,X+ ; First byte of pixel data C7B9: 4F CLRA ; Make it a word with leading 0s C7BA: 54 LSRB ; Shift ... C7BB: 46 RORA ; ... right ... C7BC: 54 LSRB ; ... two ... C7BD: 46 RORA ; ... C7BE: 54 LSRB ; ... C7BF: 46 RORA ; ... C7C0: 54 LSRB ; ... C7C1: 46 RORA ; ... pixels C7C2: 34 06 PSHS B,A ; Hold this C7C4: E6 80 LDB ,X+ ; Second byte of pixel data C7C6: 4F CLRA ; Make it a word with leading 0s C7C7: 54 LSRB ; Shift ... C7C8: 46 RORA ; ... right ... C7C9: 54 LSRB ; ... two ... C7CA: 46 RORA ; ... C7CB: 54 LSRB ; ... C7CC: 46 RORA ; ... C7CD: 54 LSRB ; ... C7CE: 46 RORA ; ... pixels C7CF: EB E4 ADDB ,S ; Combine pixels ... C7D1: E7 E4 STB ,S ; ... in middle byte C7D3: 34 02 PSHS A ; Third byte C7D5: A6 A6 LDA A,Y ; Mask ... C7D7: A4 42 ANDA 2,U ; ... screen ... C7D9: AB E4 ADDA ,S ; ... add pixels ... C7DB: A7 42 STA 2,U ; ... to screen C7DD: E6 61 LDB 1,S ; 2nd byte C7DF: A6 A5 LDA B,Y ; Mask ... C7E1: A4 41 ANDA 1,U ; ... screen ... C7E3: AB 61 ADDA 1,S ; ... add pixels ... C7E5: A7 41 STA 1,U ; ... to screen C7E7: E6 62 LDB 2,S ; 3rd byte C7E9: A6 A5 LDA B,Y ; Mask ... C7EB: A4 C4 ANDA ,U ; ... screen ... C7ED: AB 62 ADDA 2,S ; ... add pixels ... C7EF: A7 C4 STA ,U ; ... to screen C7F1: 32 63 LEAS 3,S ; Pull the 3-byte temporary C7F3: 33 C8 20 LEAU $20,U ; Next row C7F6: 6A E4 DEC ,S ; All rows done? C7F8: 26 BD BNE $C7B7 ; No ... keep going C7FA: 20 5C BRA $C858 ; Yes ... done ; ; One pixel shift right C7FC: E6 80 LDB ,X+ ; First byte of pixel data C7FE: 4F CLRA ; Make it a word with leading 0s C7FF: 54 LSRB ; Shift ... C800: 46 RORA ; ... right ... C801: 54 LSRB ; ... one ... C802: 46 RORA ; ... pixel C803: 34 06 PSHS B,A ; Hold this C805: E6 80 LDB ,X+ ; Second byte of pixel data C807: 4F CLRA ; Make it a word with leading 0s C808: 54 LSRB ; Shift ... C809: 46 RORA ; ... right ... C80A: 54 LSRB ; ... one ... C80B: 46 RORA ; ... pixel C80C: EB E4 ADDB ,S ; Combine pixels ... C80E: E7 E4 STB ,S ; ... in middle byte C810: 34 02 PSHS A ; Third byte C812: A6 A6 LDA A,Y ; Mask ... C814: A4 42 ANDA 2,U ; ... screen ... C816: AB E4 ADDA ,S ; ... add pixels ... C818: A7 42 STA 2,U ; ... to screen C81A: E6 61 LDB 1,S ; 2nd byte C81C: A6 A5 LDA B,Y ; Mask ... C81E: A4 41 ANDA 1,U ; ... screen ... C820: AB 61 ADDA 1,S ; ... add pixels ... C822: A7 41 STA 1,U ; ... to screen C824: E6 62 LDB 2,S ; 3rd byte C826: A6 A5 LDA B,Y ; Mask ... C828: A4 C4 ANDA ,U ; ... screen ... C82A: AB 62 ADDA 2,S ; ... add pixels ... C82C: A7 C4 STA ,U ; ... to screen C82E: 32 63 LEAS 3,S ; Pull the 3-byte temporary C830: 33 C8 20 LEAU $20,U ; Next row C833: 6A E4 DEC ,S ; All rows done? C835: 26 C5 BNE $C7FC ; No ... keep going C837: 20 1F BRA $C858 ; All done ; ; Draw with no shift C839: EC 81 LDD ,X++ ; Pixel data C83B: 34 06 PSHS B,A ; Hold it C83D: A6 A6 LDA A,Y ; Look up mask for value C83F: A4 C4 ANDA ,U ; Get pixels from screen C841: AB E4 ADDA ,S ; Add in the image pixels C843: A7 C4 STA ,U ; To the screen C845: E6 61 LDB 1,S ; 2nd byte C847: A6 A5 LDA B,Y ; Look up mask for value C849: A4 41 ANDA 1,U ; Get pixels from screen C84B: AB 61 ADDA 1,S ; Add in the image pixels C84D: A7 41 STA 1,U ; To the screen C84F: 32 62 LEAS 2,S ; Pop the temporaries C851: 33 C8 20 LEAU $20,U ; Next row C854: 6A E4 DEC ,S ; All rows done? C856: 26 E1 BNE $C839 ; No ... keep going C858: 35 54 PULS B,X,U ; Restore C85A: 39 RTS ; Done Erase8x8: ; X = object pointer (has X,Y coordinate) ; U = pointer to data (8x8 pixels = 16 bytes) C85B: C6 08 LDB #$08 ; 8 rows C85D: 34 54 PSHS U,X,B ; Hold these C85F: 17 01 50 LBSR GetScreenAndShift ; Get pointer to screen memory C862: 10 8E 03 80 LDY #$0380 ; Mask table C866: AE 63 LDX 3,S ; Incoming U (data pointer) to X C868: 5D TSTB ; 0 means ... C869: 10 27 00 B8 LBEQ $C925 ; ... erase with no shift C86D: 5A DECB ; 1 means ... C86E: 10 27 00 7C LBEQ $C8EE ; ... one pixel shift right C872: 5A DECB ; 2 means ... C873: 10 27 00 38 LBEQ $C8AF ; ... two pixel shift right ; ; One pixel shift left (three pixel shift right) C877: E6 80 LDB ,X+ ; First byte of pixel data C879: 4F CLRA ; Make it a word with leading 0s C87A: 58 ASLB ; Shift ... C87B: 49 ROLA ; ... left ... C87C: 58 ASLB ; ... one ... C87D: 49 ROLA ; ... pixel C87E: 34 06 PSHS B,A ; Hold this C880: E6 80 LDB ,X+ ; Second byte of pixel data C882: 4F CLRA ; Make it a word with leading 0s C883: 58 ASLB ; Shift ... C884: 49 ROLA ; ... left ... C885: 58 ASLB ; ... one ... C886: 49 ROLA ; ... pixel C887: AB 61 ADDA 1,S ; Combine pixels ... C889: A7 61 STA 1,S ; ... in middle byte C88B: 34 04 PSHS B ; Third byte C88D: A6 A5 LDA B,Y ; Mask ... C88F: A4 42 ANDA 2,U ; ... screen ... C891: A7 42 STA 2,U ; ... to screen C893: E6 62 LDB 2,S ; 2nd byte C895: A6 A5 LDA B,Y ; Mask ... C897: A4 41 ANDA 1,U ; ... screen ... C899: A7 41 STA 1,U ; ... to screen C89B: E6 61 LDB 1,S ; 3rd byte C89D: A6 A5 LDA B,Y ; Mask ... C89F: A4 C4 ANDA ,U ; ... screen ... C8A1: A7 C4 STA ,U ; ... to screen C8A3: 32 63 LEAS 3,S ; Pull the 3-byte temporary C8A5: 33 C8 20 LEAU $20,U ; Next row C8A8: 6A E4 DEC ,S ; All rows done? C8AA: 26 CB BNE $C877 ; No ... keep going C8AC: 16 00 91 LBRA $C940 ; yest ... done ; ; Two pixel shift right C8AF: E6 80 LDB ,X+ ; First byte of pixel data C8B1: 4F CLRA ; Make it a word with leading 0s C8B2: 54 LSRB ; Shift ... C8B3: 46 RORA ; ... right ... C8B4: 54 LSRB ; ... two ... C8B5: 46 RORA ; ... C8B6: 54 LSRB ; ... C8B7: 46 RORA ; ... C8B8: 54 LSRB ; ... C8B9: 46 RORA ; ... pixels C8BA: 34 06 PSHS B,A ; Hold this C8BC: E6 80 LDB ,X+ ; Second byte of pixel data C8BE: 4F CLRA ; Shift ... C8BF: 54 LSRB ; ... right ... C8C0: 46 RORA ; ... two C8C1: 54 LSRB ; ... C8C2: 46 RORA ; ... C8C3: 54 LSRB ; ... C8C4: 46 RORA ; ... C8C5: 54 LSRB ; ... C8C6: 46 RORA ; ... pixels C8C7: EB E4 ADDB ,S ; Combine pixels ... C8C9: E7 E4 STB ,S ; ... in middle byte C8CB: 34 02 PSHS A ; Third byte C8CD: A6 A6 LDA A,Y ; Mask ... C8CF: A4 42 ANDA 2,U ; ... screen ... C8D1: A7 42 STA 2,U ; ... to screen C8D3: E6 61 LDB 1,S ; Second byte C8D5: A6 A5 LDA B,Y ; Mask ... C8D7: A4 41 ANDA 1,U ; ... screen ... C8D9: A7 41 STA 1,U ; ... to screen C8DB: E6 62 LDB 2,S ; Third byte C8DD: A6 A5 LDA B,Y ; Mask ... C8DF: A4 C4 ANDA ,U ; ... screen ... C8E1: A7 C4 STA ,U ; ... to screen C8E3: 32 63 LEAS 3,S ; Pull the 3-byte temporary C8E5: 33 C8 20 LEAU $20,U ; Next row C8E8: 6A E4 DEC ,S ; All rows done? C8EA: 26 C3 BNE $C8AF ; No ... keep going C8EC: 20 52 BRA $C940 ; Yes ... done ; ; One pixel shift right C8EE: E6 80 LDB ,X+ ; First byte of pixel data C8F0: 4F CLRA ; Make it a word with leading 0s C8F1: 54 LSRB ; Shift ... C8F2: 46 RORA ; ... right ... C8F3: 54 LSRB ; ... one ... C8F4: 46 RORA ; ... pixel C8F5: 34 06 PSHS B,A ; Hold this C8F7: E6 80 LDB ,X+ ; Second byte of pixel data C8F9: 4F CLRA ; Make it a word with leading 0s C8FA: 54 LSRB ; Shift ... C8FB: 46 RORA ; ... right ... C8FC: 54 LSRB ; ... one ... C8FD: 46 RORA ; ... pixel C8FE: EB E4 ADDB ,S ; Combine pixels ... C900: E7 E4 STB ,S ; ... in middle byte C902: 34 02 PSHS A ; Third byte C904: A6 A6 LDA A,Y ; Mask ... C906: A4 42 ANDA 2,U ; ... screen ... C908: A7 42 STA 2,U ; ... to screen C90A: E6 61 LDB 1,S ; 2nd byte C90C: A6 A5 LDA B,Y ; Mask ... C90E: A4 41 ANDA 1,U ; ... screen ... C910: A7 41 STA 1,U ; ... to screen C912: E6 62 LDB 2,S ; Third byte C914: A6 A5 LDA B,Y ; Mask ... C916: A4 C4 ANDA ,U ; ... screen ... C918: A7 C4 STA ,U ; ... to screen C91A: 32 63 LEAS 3,S ; Pull the 3 byte temporary C91C: 33 C8 20 LEAU $20,U ; Next row C91F: 6A E4 DEC ,S ; All rows done? C921: 26 CB BNE $C8EE ; No ... keep going C923: 20 1B BRA $C940 ; All done ; ; Erase with no shift C925: EC 81 LDD ,X++ ; Pixel data C927: 34 06 PSHS B,A ; Hold it C929: A6 A6 LDA A,Y ; Look up mask for value C92B: A4 C4 ANDA ,U ; Mask screen C92D: A7 C4 STA ,U ; Back to screen C92F: E6 61 LDB 1,S ; 2nd byte C931: A6 A5 LDA B,Y ; Look up mask for value C933: A4 41 ANDA 1,U ; Mas screen C935: A7 41 STA 1,U ; Back to screen C937: 32 62 LEAS 2,S ; Pop the temporaries C939: 33 C8 20 LEAU $20,U ; Next row C93C: 6A E4 DEC ,S ; All rows done? C93E: 26 E5 BNE $C925 ; No ... keep going C940: 35 54 PULS B,X,U ; Restore C942: 39 RTS ; Done
Print a Sequence of Characters
Characters here are 8x8 tiles that form images on the screen. This is only ever used for printing text areas, but there are no patterns for individual letters. See the actual graphics patterns decoded below.
PrintChars: ; A = X coordinate ; B = Y coordinate ; U = text string C943: 8E 00 E4 LDX #$00E4 ; Utility descriptor C946: A7 84 STA ,X ; Set the X coordinate C948: E7 02 STB 2,X ; Set the Y coordinate C94A: E6 5F LDB -1,U ; Characters ... C94C: E7 04 STB 4,X ; ... to print C94E: 17 FE 0C LBSR Draw8x8 ; C951: 33 C8 10 LEAU $10,U ; Next image C954: A6 84 LDA ,X ; X coordinate C956: 8B 08 ADDA #$08 ; Next character ... C958: A7 84 STA ,X ; ... over C95A: 6A 04 DEC 4,X ; All done? C95C: 26 F0 BNE $C94E ; No ... do all C95E: 39 RTS ; Done
Set and Clear Pixel
These functions manipulate individual pixels by X,Y coordinate. This is used to draw the cursive "doubleback" on the splash screen. And it is used to draw the player's head pixel.
This code captures the pixel value from the screen before overwriting it. This value is used for collision detection for the player.
SetPixel: C95F: 17 00 50 LBSR GetScreenAndShift ; C962: A6 C4 LDA ,U ; Value from screen C964: 5D TSTB ; Shift 0 means ... C965: 26 0A BNE $C971 ; ... upper pixel C967: 84 3F ANDA #$3F ; Mask off upper pixel ..111111 C969: 1F 89 TFR A,B ; Return the bits ... (used by collision detection)) C96B: E0 C4 SUBB ,U ; ... we removed C96D: 8A 80 ORA #$80 ; OR in the upper pixel C96F: 20 22 BRA $C993 ; Set and done ; C971: 5A DECB ; Shift 1 means ... C972: 26 0A BNE $C97E ; ... 2nd pixel C974: 84 CF ANDA #$CF ; Mask off the 2nd pixel 11..1111 C976: 1F 89 TFR A,B ; Return the bits ... C978: E0 C4 SUBB ,U ; ... we removed C97A: 8A 20 ORA #$20 ; OR in the 2nd pixel C97C: 20 15 BRA $C993 ; Set and done ; C97E: 5A DECB ; Shift 2 means ... C97F: 26 0A BNE $C98B ; ... 3rd pixel C981: 84 F3 ANDA #$F3 ; Mask off the 3rd pixel 1111..11 C983: 1F 89 TFR A,B ; Return the bits ... C985: E0 C4 SUBB ,U ; ... we removed C987: 8A 08 ORA #$08 ; OR in the 3rd pixel C989: 20 08 BRA $C993 ; Set and done ; C98B: 84 FC ANDA #$FC ; Mask off the last pixel 111111.. C98D: 1F 89 TFR A,B ; Return the bits ... C98F: E0 C4 SUBB ,U ; ... we removed C991: 8A 02 ORA #$02 ; OR in the last pixel ; C993: A7 C4 STA ,U ; Store pixel to screen C995: 39 RTS ; Done ErasePixel: ; U = pointer to screen memory C996: A6 C4 LDA ,U ; Value from the screen C998: 5D TSTB ; Pixel shift value C999: 26 04 BNE $C99F ; Not 0 (left most pixel) ... try others C99B: 84 3F ANDA #$3F ; Mask off the left most pixel ..111111 C99D: 20 10 BRA $C9AF ; Clear the pixel C99F: 5A DECB ; Is this the 2nd pixel? C9A0: 26 04 BNE $C9A6 ; No ... try the 3rd C9A2: 84 CF ANDA #$CF ; Mask off the 2nd pixel 11..1111 C9A4: 20 09 BRA $C9AF ; Clear the pixel C9A6: 5A DECB ; Is this the 3rd pixel? C9A7: 26 04 BNE $C9AD ; No ... must be the 4th C9A9: 84 F3 ANDA #$F3 ; Mask off the 3rd pixel 1111..11 C9AB: 20 02 BRA $C9AF ; Clear the pixel C9AD: 84 FC ANDA #$FC ; Mask off the 4th pixel 111111.. C9AF: A7 C4 STA ,U ; Clear the pixel on the screen C9B1: 39 RTS ; Done
Get Screen Pointer and Pixel Number
This decodes an X,Y coordinate to a pointer to screen memory. Since each byte of memory holds 4 pixels, this routine also returns the pixel number within that byte.
GetScreenAndShift:
; Ultimately, the equation for screen pointer is: Y*32 + X/4.
; This code cleverly does:
; (Y*256 + X*2) / 8 =
; (Y*128 + X) / 4 =
; Y*32 + X/4
; Input: X pointer to object structure
; Mangle: A, Y
; Return: U screen pointer
; Return: B shift amount
C9B2: E6 84 LDB ,X ; The object's X coordinate
C9B4: A6 02 LDA 2,X ; The object's Y coordinate
C9B6: 58 ASLB ; D = Y*256 + X*2
C9B7: 47 ASRA ; Divide ...
C9B8: 56 RORB ; ...
C9B9: 47 ASRA ; ...
C9BA: 56 RORB ; ...
C9BB: 47 ASRA ; ...
C9BC: 56 RORB ; ... eight
C9BD: 10 8E 04 00 LDY #$0400 ; Start of screen memory
C9C1: 33 AB LEAU D,Y ; Point into screen memory
C9C3: E6 84 LDB ,X ; X coordinate
C9C5: C4 03 ANDB #$03 ; 4 pixels per byte ... 4 possible shifts
C9C7: 39 RTS ; Done
Move an Object by its DeltaX and DeltaY
This function works on the bytes within a single object structure. The X and Y coordinate are considered to be words in the object structure, but the deltas are single bytes.
MoveObject: ; coordinates = coordinates + 8 * delta (with limits) C9C8: E6 04 LDB 4,X ; Word ... C9CA: 1D SEX ; ... deltaX C9CB: 58 ASLB ; Multiply ... C9CC: 49 ROLA ; ... C9CD: 58 ASLB ; ... C9CE: 49 ROLA ; ... deltaX ... C9CF: 58 ASLB ; ... C9D0: 49 ROLA ; ... by 8 C9D1: E3 84 ADDD ,X ; Add to the 2-byte X coordiante C9D3: 80 03 SUBA #$03 ; Temporarily translate for contraining C9D5: 81 7B CMPA #$7B ; X coordinate too high? C9D7: 25 07 BLO $C9E0 ; No ... keep it C9D9: 86 7A LDA #$7A ; Yes ... constrain it C9DB: 6D 04 TST 4,X ; X coordinate too low? C9DD: 2A 01 BPL $C9E0 ; No ... keep it C9DF: 4F CLRA ; Yes ... constrain it C9E0: 8B 03 ADDA #$03 ; Translate back to the right C9E2: ED 84 STD ,X ; Store X coordinate (integer and fractional) C9E4: E6 05 LDB 5,X ; Word ... C9E6: 1D SEX ; ... deltaY C9E7: 58 ASLB ; Multiply ... C9E8: 58 ASLB ; ... C9E9: 58 ASLB ; ... ?? why no ROLA C9EA: 49 ROLA ; ... by 8 C9EB: E3 02 ADDD 2,X ; Add to the 2-byte Y coordinate C9ED: 80 03 SUBA #$03 ; Temporarily translate for constraining C9EF: 81 53 CMPA #$53 ; Y coordinate too high? C9F1: 25 07 BLO $C9FA ; No ... keep it C9F3: 86 52 LDA #$52 ; Yes ... constrain it C9F5: 6D 05 TST 5,X ; Y coordinate too low? C9F7: 2A 01 BPL $C9FA ; No ... keep it C9F9: 4F CLRA ; Yes ... constrain it C9FA: 8B 03 ADDA #$03 ; Translate back down C9FC: ED 02 STD 2,X ; Store Y coordinate (integer and fractional) C9FE: 39 RTS ; Done
Follow the Player
This code moves the given object towards the player's head point. The absolute delta speeds are given in A and B. The code changes the sign as needed.
FollowPlayer: ; X = object to move C9FF: A7 04 STA 4,X ; Store the deltaX ... CA01: E7 05 STB 5,X ; ... and deltaY CA03: CE 00 D8 LDU #$00D8 ; Player object to U CA06: A6 84 LDA ,X ; Objects are 8 pixels wide. Get ... CA08: 8B 04 ADDA #$04 ; ... the center X of the object CA0A: A7 84 STA ,X ; Update coordinate CA0C: A0 C4 SUBA ,U ; Compare object X to player X CA0E: 2B 07 BMI $CA17 ; Object X is less ... keep deltaX CA10: 60 04 NEG 4,X ; Reverse direction on deltaX CA12: 4D TSTA ; Are the coordinates the same? CA13: 26 02 BNE $CA17 ; No ... keep this CA15: 6F 04 CLR 4,X ; Yes ... no movement on X axis ; CA17: E6 04 LDB 4,X ; DeltaX to B CA19: A6 02 LDA 2,X ; Objects are 8 pixels tall. Get ... CA1B: 8B 04 ADDA #$04 ; ... the center Y of the object CA1D: A7 02 STA 2,X ; Update coordinate CA1F: A0 42 SUBA 2,U ; Compare object Y to player Y CA21: 2B 07 BMI $CA2A ; Object Y is less ... keep deltaY CA23: 60 05 NEG 5,X ; Reverse direction on deltaY CA25: 4D TSTA ; Are the coordinates the same? CA26: 26 02 BNE $CA2A ; No ... keep this CA28: 6F 05 CLR 5,X ; Yes ... no movement on Y axis ; CA2A: 17 FF 9B LBSR MoveObject ; Move the object towards the player CA2D: A6 84 LDA ,X ; X coordinate CA2F: 80 04 SUBA #$04 ; Translate back to upper left corner CA31: 81 03 CMPA #$03 ; Is coordinate too small? CA33: 2C 02 BGE $CA37 ; No ... keep it. CA35: 86 03 LDA #$03 ; Yes ... constrain to X>=3 CA37: 81 76 CMPA #$76 ; Is coordinate too big? CA39: 2F 02 BLE $CA3D ; No ... keep it CA3B: 86 76 LDA #$76 ; Yes ... constrain to X<=118 CA3D: A7 84 STA ,X ; Update the object's X coordiante CA3F: A6 02 LDA 2,X ; Get the Y coordinate CA41: 80 04 SUBA #$04 ; Translate back to the upper left corner CA43: 81 03 CMPA #$03 ; Is coordinate too small? CA45: 2C 02 BGE $CA49 ; No ... keep it. CA47: 86 03 LDA #$03 ; Yes ... constrain to Y>=3 CA49: 81 4E CMPA #$4E ; Is coordinate too big? CA4B: 2F 02 BLE $CA4F ; No ... keep it CA4D: 86 4E LDA #$4E ; Yes ... constrain to Y<=78 CA4F: A7 02 STA 2,X ; Update the object's Y coordinate CA51: 39 RTS ; Done ClearScreen: CA52: 5F CLRB ; Clear value is black FillScreen: CA53: CE 04 00 LDU #$0400 ; Start of screen CA56: 33 C9 0C 00 LEAU $0C00,U ; Now to the end of screen CA5A: E7 C2 STB ,-U ; Store value ... CA5C: 11 83 04 00 CMPU #$0400 ; ... to the ... CA60: 22 F8 BHI $CA5A ; ... screen CA62: 39 RTS ; Done DrawPlayfiled: CA63: CE 04 00 LDU #$0400 ; Start of screen CA66: 33 C8 60 LEAU $60,U ; 3rd row down CA69: 86 53 LDA #$53 ; 83 rows in the playfield CA6B: C6 F0 LDB #$F0 ; 2 pixels on the left ... CA6D: E7 C0 STB ,U+ ; ... are white CA6F: C6 1E LDB #$1E ; Clear ... CA71: 6F C0 CLR ,U+ ; ... 30 columns ... CA73: 5A DECB ; ... on each ... CA74: 26 FB BNE $CA71 ; ... row CA76: C6 0F LDB #$0F ; 2 pixels on the right ... CA78: E7 C0 STB ,U+ ; ... are white CA7A: 4A DECA ; Do ... CA7B: 26 EE BNE $CA6B ; ... all rows CA7D: 39 RTS ; Done
Play Song
PlaySong: CA7E: 7F FF 20 CLR PIA1_DA ; D/A to 0 CA81: BD A9 76 JSR $A976 ; Enable analog mux CA84: 17 00 39 LBSR CheckForBreak ; CA87: EC C1 LDD ,U++ ; Get next data CA89: 27 34 BEQ $CABF ; No more ... done CA8B: 34 06 PSHS B,A ; Audio timing magic CA8D: 1F 98 TFR B,A ; Audio timing magic CA8F: 4A DECA ; Delay amount CA90: 1E 11 EXG X,X ; Small ... CA92: 1E 11 EXG X,X ; ... CA94: 1E 11 EXG X,X ; ... CA96: 1E 11 EXG X,X ; ... delay CA98: 26 F5 BNE $CA8F ; Finish the delay CA9A: 86 3C LDA #$3C ; 6 bit D/A to ... CA9C: B7 FF 20 STA PIA1_DA ; ... 111100 CA9F: 1F 98 TFR B,A ; Audio timing magic CAA1: A0 61 SUBA 1,S ; Audio timing magic CAA3: 43 COMA ; Audio timing magic CAA4: 4A DECA ; Delay amount CAA5: 1E 11 EXG X,X ; Small ... CAA7: 1E 11 EXG X,X ; ... CAA9: 1E 11 EXG X,X ; ... CAAB: 1E 11 EXG X,X ; ... delay CAAD: 26 F5 BNE $CAA4 ; Finish the delay CAAF: 7F FF 20 CLR PIA1_DA ; D/A to 0 CAB2: 5A DECB ; Audio timing magic CAB3: 26 02 BNE $CAB7 ; Audio timing magic CAB5: E6 61 LDB 1,S ; Audio timing magic CAB7: 6A E4 DEC ,S ; Audio timing magic CAB9: 26 D2 BNE $CA8D ; Audio timing magic CABB: 35 06 PULS A,B ; Audio timing magic CABD: 20 BF BRA PlaySong ; Play until end CABF: 39 RTS ; Done CheckForBreak: CAC0: C6 FB LDB #$FB ; All high but ... CAC2: F7 FF 02 STB PIA0_DB ; ... BREAK column CAC5: F6 FF 00 LDB PIA0_DA ; Read keyboard rows CAC8: C4 40 ANDB #$40 ; Is BREAK row low? CACA: 10 27 F5 36 LBEQ Reset ; Yes ...break is pressed ... restart CACE: 39 RTS ; Break not pressed ... continue SetVideoMode: ; Set mode 128x96 Color Graphics ; Set display offset to $400 ; V2 V1 V0 7 6 5 4 3 2 1 0 ; 1 0 0 1 1 1 1 1 x x x CACF: 8D 1E BSR WaitVBlank ; Wait for VBLANK CAD1: 8E FF C6 LDX #$FFC6 ; Set ... CAD4: E7 84 STB ,X ; ... display ... 000010 CAD6: E7 03 STB 3,X ; ... offset to ... CAD8: E7 04 STB 4,X ; ... 00010 ... CADA: E7 06 STB 6,X ; ... 0.5K * 2 = 1K ... CADC: E7 08 STB 8,X ; ... ... CADE: E7 0A STB 10,X ; ... address=$400 CAE0: F7 FF C0 STB dispMode ; V0=0 CAE3: F7 FF C2 STB dispMode+2 ; V1=0 CAE6: F7 FF C5 STB dispMode+5 ; V2=1 (Mode 100 = G3C) CAE9: C6 F8 LDB #$F8 ; Bright screen ... CAEB: F7 FF 22 STB PIA1_DB ; ... color mode CAEE: 39 RTS ; Cone WaitVBlank: CAEF: 7D FF 02 TST PIA0_DB ; ??? why read the keyboard register? It doesn't clear anything CAF2: 0C D7 INC random ; ?? randomness? CAF4: 7D FF 03 TST PIA0_CB ; Wait for ... CAF7: 2A F9 BPL $CAF2 ; ... vertical blank CAF9: 39 RTS ; Cone
Data From Here Down
Game Objects
ImageApple:
; Object type 1
CAFA: 00 80 ; ....2...
CAFC: 16 50 ; .11211..
CAFE: 55 54 ; 1111111.
CB00: 55 D4 ; 1111311.
CB02: 55 D4 ; 1111311.
CB04: 15 50 ; .11111..
CB06: 05 40 ; ..111...
CB08: 00 00 ; ........
ImageCherry:
; Object type 2
CB0A: 00 20 ; .....2..
CB0C: 00 80 ; ....2...
CB0E: 02 20 ; ...2.2..
CB10: 08 14 ; ..2..11.
CB12: 14 5D ; .11.1131
CB14: 5D 55 ; 11311111
CB16: 55 14 ; 1111.11.
CB18: 14 00 ; .11.....
ImageMagnet:
; Object type 3
CB1A: 0A A0 ; ..2222..
CB1C: 2A A8 ; .222222.
CB1E: A8 2A ; 222..222
CB20: A0 0A ; 22....22
CB22: A0 0A ; 22....22
CB24: A0 0A ; 22....22
CB26: 28 28 ; .22..22.
CB28: 28 28 ; .22..22.
ImageSkate:
; Object type 4 ; 2 images CB2A: FC 00 ; 333..... CB2C: F7 00 ; 3313.... CB2E: FF 74 ; 3333131. CB30: FF FF ; 33333333 CB32: 55 55 ; 11111111 CB34: 10 04 ; .1....1. CB36: 54 15 ; 111..111 CB38: 10 04 ; .1....1. ; CB3A: FC 00 ; 333..... CB3C: F7 00 ; 3313.... CB3E: FF 74 ; 3333131. CB40: FF FF ; 33333333 CB42: 55 55 ; 11111111 CB44: 44 11 ; 1.1..1.1 CB46: 10 04 ; .1....1. CB48: 44 11 ; 1.1..1.1 ImageYoYo:
; Object type 5 ; 5 images CB4A: 00 10 ; .....1.. CB4C: 0A 90 ; ..2221.. CB4E: 2A A0 ; .22222.. CB50: AA A8 ; 2222222. CB52: FF FC ; 3333333. CB54: AA A8 ; 2222222. CB56: 2A A0 ; .22222.. CB58: 0A 80 ; ..222... ; CB5A: 00 10 ; .....1.. CB5C: 0A 90 ; ..2221.. CB5E: 2A B0 ; .22223.. CB60: AA E8 ; 2222322. CB62: AB A8 ; 2223222. CB64: AE A8 ; 2232222. CB66: 3A A0 ; .32222.. CB68: 0A 80 ; ..222... ; CB6A: 00 10 ; .....1.. CB6C: 0B 90 ; ..2321.. CB6E: 2B A0 ; .22322.. CB70: AB A8 ; 2223222. CB72: AB A8 ; 2223222. CB74: AB A8 ; 2223222. CB76: 2B A0 ; .22322.. CB78: 0B 80 ; ..232... ; CB7A: 00 10 ; .....1.. CB7C: 0A 90 ; ..2221.. CB7E: 3A A0 ; .32222.. CB80: AE A8 ; 2232222. CB82: AB A8 ; 2223222. CB84: AA E8 ; 2222322. CB86: 2A B0 ; .22223.. CB88: 0A 80 ; ..222... ; CB8A: 00 00 ; ........ CB8C: 0A 80 ; ..222... CB8E: 2A A0 ; .22222.. CB90: AA A8 ; 2222222. CB92: AA A8 ; 2222222. CB94: AA A8 ; 2222222. CB96: 2A A0 ; .22222.. CB98: 0A 80 ; ..222... StringEraser: CB9A: 00 30 ; .....3.. CB9C: 00 30 ; .....3.. CB9E: 00 30 ; .....3.. CBA0: 00 30 ; .....3.. CBA2: 00 30 ; .....3.. CBA4: 00 30 ; .....3.. CBA6: 00 30 ; .....3.. CBA8: 00 30 ; .....3.. ImageSkull:
; Object type 8
CBAA: 0F C0 ; ..333...
CBAC: 3F F0 ; .33333..
CBAE: 37 70 ; .31313..
CBB0: 3F F0 ; .33333..
CBB2: 0F C0 ; ..333...
CBB4: CF CC ; 3.333.3.
CBB6: 30 30 ; .3...3..
CBB8: C0 0C ; 3.....3.
ImagePear:
; Object type 6
CBBA: 00 10 ; .....1..
CBBC: 00 40 ; ....1...
CBBE: 00 C0 ; ....3...
CBC0: 03 C0 ; ...33...
CBC2: 0F F0 ; ..3333..
CBC4: 3F F0 ; .33333..
CBC6: 3F F0 ; .33333..
CBC8: 0F C0 ; ..333...
ImageSpider:
; Object type 7 ; 2 images CBCA: 04 10 ; ..1..1.. CBCC: 44 11 ; 1.1..1.1 CBCE: 12 84 ; .1.22.1. CBD0: 06 90 ; ..1221.. CBD2: 06 90 ; ..1221.. CBD4: 12 84 ; .1.22.1. CBD6: 42 81 ; 1..22..1 CBD8: 40 01 ; 1......1 ; CBDA: 04 10 ; ..1..1.. CBDC: 04 10 ; ..1..1.. CBDE: 02 80 ; ...22... CBE0: 56 95 ; 11122111 CBE2: 02 80 ; ...22... CBE4: 16 94 ; .112211. CBE6: 42 81 ; 1..22..1 CBE8: 00 00 ; ........ ImageX:
; Object type 9 ; 2 images CBEA: 00 00 ; ........ CBEC: 00 00 ; ........ CBEE: 08 20 ; ..2..2.. CBF0: 02 80 ; ...22... CBF2: 02 80 ; ...22... CBF4: 08 20 ; ..2..2.. CBF6: 00 00 ; ........ CBF8: 00 00 ; ........ ; CBFA: 80 02 ; 2......2 CBFC: 20 08 ; .2....2. CBFE: 08 20 ; ..2..2.. CC00: 02 80 ; ...22... CC02: 02 80 ; ...22... CC04: 08 20 ; ..2..2.. CC06: 20 08 ; .2....2. CC08: 80 02 ; 2......2 LifeIndicator:
; Inactive CC0A: AA 80 ; 22222... CC0C: 00 00 ; ........ CC0E: 00 00 ; ........ CC10: 00 00 ; ........ CC12: 00 00 ; ........ CC14: 00 00 ; ........ CC16: 00 00 ; ........ CC18: 00 00 ; ........ ; Active CC1A: 55 40 ; 11111... CC1C: 00 00 ; ........ CC1E: 00 00 ; ........ CC20: 00 00 ; ........ CC22: 00 00 ; ........ CC24: 00 00 ; ........ CC26: 00 00 ; ........ CC28: 00 00 ; ........ CC2A: 02 ; 2 tiles GenericEraser: ; 3333333333333333 ; 3333333333333333 ; 3333333333333333 ; 3333333333333333 ; 3333333333333333 ; 3333333333333333 ; 3333333333333333 ; 3333333333333333 ; CC2B: FF FF ; 33333333 CC2D: FF FF ; 33333333 CC2F: FF FF ; 33333333 CC31: FF FF ; 33333333 CC33: FF FF ; 33333333 CC35: FF FF ; 33333333 CC37: FF FF ; 33333333 CC39: FF FF ; 33333333 ; CC3B: FF FF ; 33333333 CC3D: FF FF ; 33333333 CC3F: FF FF ; 33333333 CC41: FF FF ; 33333333 CC43: FF FF ; 33333333 CC45: FF FF ; 33333333 CC47: FF FF ; 33333333 CC49: FF FF ; 33333333
Text Areas
CC4B: 03 ; 3 tiles
StrPlayer:
; .....1..................
; .....1..................
; 111..1..11.......11..111
; 1..1.1...1.1..1.1111.1..
; 1..1.1.111.1..1.1....1..
; 111..1.111..111..11..1..
; 1.............1.........
; 1..........111..........
;
CC4C: 00 10 ; .....1..
CC4E: 00 10 ; .....1..
CC50: 54 10 ; 111..1..
CC52: 41 10 ; 1..1.1..
CC54: 41 11 ; 1..1.1.1
CC56: 54 11 ; 111..1.1
CC58: 40 00 ; 1.......
CC5A: 40 00 ; 1.......
;
CC5C: 00 00 ; ........
CC5E: 00 00 ; ........
CC60: 50 00 ; 11......
CC62: 11 04 ; .1.1..1.
CC64: 51 04 ; 11.1..1.
CC66: 50 54 ; 11..111.
CC68: 00 04 ; ......1.
CC6A: 01 50 ; ...111..
;
CC6C: 00 00 ; ........
CC6E: 00 00 ; ........
CC70: 14 15 ; .11..111
CC72: 55 10 ; 1111.1..
CC74: 40 10 ; 1....1..
CC76: 14 10 ; .11..1..
CC78: 00 00 ; ........
CC7A: 00 00 ; ........
CC7C: 02 ; 2 tiles
StrOne:
; ................
; ................
; ...11..111...11.
; ..1..1.1..1.1111
; ..1..1.1..1.1...
; ...11..1..1..11.
; ................
; ................
;
CC7D: 00 00 ; ........
CC7F: 00 00 ; ........
CC81: 01 41 ; ...11..1
CC83: 04 11 ; ..1..1.1
CC85: 04 11 ; ..1..1.1
CC87: 01 41 ; ...11..1
CC89: 00 00 ; ........
CC8B: 00 00 ; ........
;
CC8D: 00 00 ; ........
CC8F: 00 00 ; ........
CC91: 50 14 ; 11...11.
CC93: 04 55 ; ..1.1111
CC95: 04 40 ; ..1.1...
CC97: 04 14 ; ..1..11.
CC99: 00 00 ; ........
CC9B: 00 00 ; ........
CC9D: 02 ; 2 tiles
StrTwo:
; ................
; .1..............
; 111..1..1..11...
; .1...1..1.1..1..
; .1.1.1111.1..1..
; ..1..1111..11...
; ................
; ................
;
CC9E: 00 00 ; ........
CCA0: 10 00 ; .1......
CCA2: 54 10 ; 111..1..
CCA4: 10 10 ; .1...1..
CCA6: 11 15 ; .1.1.111
CCA8: 04 15 ; ..1..111
CCAA: 00 00 ; ........
CCAC: 00 00 ; ........
;
CCAE: 00 00 ; ........
CCB0: 00 00 ; ........
CCB2: 41 40 ; 1..11...
CCB4: 44 10 ; 1.1..1..
CCB6: 44 10 ; 1.1..1..
CCB8: 41 40 ; 1..11...
CCBA: 00 00 ; ........
CCBC: 00 00 ; ........
CCBE: 05 ; 5 tiles
StrGameOver:
; ..33333333333333333333333333333333333...
; .3333333333333333333333333333333333333..
; 332233322322223322333332233232332233222.
; 323323332322223222233323323232322223233.
; 323323222323323233333323323323323333233.
; 332223222323323322333332233323332233233.
; .3332333333333333333333333333333333333..
; .222333333333333333333333333333333333...
;
CCBF: 0F FF ; ..333333
CCC1: 3F FF ; .3333333
CCC3: FA FE ; 33223332
CCC5: EF BF ; 32332333
CCC7: EF BA ; 32332322
CCC9: FA BA ; 33222322
CCCB: 3F BF ; .3332333
CCCD: 2A FF ; .2223333
;
CCCF: FF FF ; 33333333
CCD1: FF FF ; 33333333
CCD3: BA AF ; 23222233
CCD5: BA AE ; 23222232
CCD7: BB EE ; 23233232
CCD9: BB EF ; 23233233
CCDB: FF FF ; 33333333
CCDD: FF FF ; 33333333
;
CCDF: FF FF ; 33333333
CCE1: FF FF ; 33333333
CCE3: AF FE ; 22333332
CCE5: AB FB ; 22233323
CCE7: FF FB ; 33333323
CCE9: AF FE ; 22333332
CCEB: FF FF ; 33333333
CCED: FF FF ; 33333333
;
CCEF: FF FF ; 33333333
CCF1: FF FF ; 33333333
CCF3: BE EF ; 23323233
CCF5: EE EE ; 32323232
CCF7: EF BE ; 32332332
CCF9: BF BF ; 23332333
CCFB: FF FF ; 33333333
CCFD: FF FF ; 33333333
;
CCFF: FF C0 ; 33333...
CD01: FF F0 ; 333333..
CD03: AF A8 ; 2233222.
CD05: AB BC ; 2223233.
CD07: FF BC ; 3333233.
CD09: AF BC ; 2233233.
CD0B: FF F0 ; 333333..
CD0D: FF C0 ; 33333...
CD0F: 06 ; Six tiles
Str1or2Players:
;. 3...........33.........1.......................
; 33..111.11..3..3...111..1.......................
; .3..1.1.1.....3....1..1.1..11.1..1..11..111..11.
; .3..1.1.1....3.....1..1.1...1.1..1.1111.1...1...
; .3..111.1...3......1..1.1.111.1..1.1....1....11.
; 333.........3333...111..1.111..111..11..1...11..
; ...................1.............1..............
; ...................1...........111..............
;
CD10: 30 00 ; .3......
CD12: F0 54 ; 33..111.
CD14: 30 44 ; .3..1.1.
CD16: 30 44 ; .3..1.1.
CD18: 30 54 ; .3..111.
CD1A: FC 00 ; 333.....
CD1C: 00 00 ; ........
CD1E: 00 00 ; ........
;
CD20: 00 3C ; .....33.
CD22: 50 C3 ; 11..3..3
CD24: 40 0C ; 1.....3.
CD26: 40 30 ; 1....3..
CD28: 40 C0 ; 1...3...
CD2A: 00 FF ; ....3333
CD2C: 00 00 ; ........
CD2E: 00 00 ; ........
;
CD30: 00 00 ; ........
CD32: 01 50 ; ...111..
CD34: 01 04 ; ...1..1.
CD36: 01 04 ; ...1..1.
CD38: 01 04 ; ...1..1.
CD3A: 01 50 ; ...111..
CD3C: 01 00 ; ...1....
CD3E: 01 00 ; ...1....
;
CD40: 40 00 ; 1.......
CD42: 40 00 ; 1.......
CD44: 41 44 ; 1..11.1.
CD46: 40 44 ; 1...1.1.
CD48: 45 44 ; 1.111.1.
CD4A: 45 41 ; 1.111..1
CD4C: 00 00 ; ........
CD4E: 00 01 ; .......1
;
CD50: 00 00 ; ........
CD52: 00 00 ; ........
CD54: 10 50 ; .1..11..
CD56: 11 54 ; .1.1111.
CD58: 11 00 ; .1.1....
CD5A: 50 50 ; 11..11..
CD5C: 10 00 ; .1......
CD5E: 50 00 ; 11......
;
CD60: 00 00 ; ........
CD62: 00 00 ; ........
CD64: 54 14 ; 111..11.
CD66: 40 40 ; 1...1...
CD68: 40 14 ; 1....11.
CD6A: 40 50 ; 1...11..
CD6C: 00 00 ; ........
CD6E: 00 00 ; ........
; Copyright message in 3 lines of tiles ; ........ ; ........ ; ........ ; ........ ; ........ ; ........ ; .2222... ; 2....2.. ; .......2..22..2..2..22...22...22................................................ ; .......2.2....2.22.2..2.2..2.2..2......22...2..2...222...2...222..2..22......... ; .......2.2....2..2..222..22....2.......2.2.2.2.2...2.....2...2...2.2.2.2........ ; .......2..22..2..2....2.2..2..2........2.2.222.2...22....2...22..222.22......... ; ........2....2..222.22...22..2222......22..2.2.222.222...222.222.2.2.2.2........ ; .........2222................................................................... ; ........................................22222.22..2..2.222..2.2................. ; 2...2..22.222.2..2..22.222.22...222..2....2..2..2.22.2.2..2.2.2...22..2..22..22. ; 2...2.2...2...22.2.2...2...2.2...2..2.2...2..2..2.22.2.2..2.222..2...2.2.2.2.2.2 ; 2...2.2...22..2.22..22.22..2.2...2..2.2...2..2222.2.22.2..2..2...2...2.2.22..22. ; 222.2..22.222.2..2.22..222.22....2...2....2..2..2.2.22.222...2....22..2..2.2.2.. ; ................................................................................ ; .......2..2...2.....22..2..22.2.2.222..22...22..222..22.222.22..2.2.222.22...... ; ......2.2.2...2.....2.2.2.2...2.2..2..2.....2.2.2...2...2...2.2.2.2.2...2.2..... ; ......222.2...2.....22..2.2.2.222..2...22...22..22...22.22..22..2.2.22..2.2..... ; ......2.2.222.222...2.2.2..22.2.2..2..22....2.2.222.22..222.2.2..2..222.22...... CD70: 01 ; 1 tile StrCopyright1: CD71: 00 00 ; ........ CD73: 00 00 ; ........ CD75: 00 00 ; ........ CD77: 00 00 ; ........ CD79: 00 00 ; ........ CD7B: 00 00 ; ........ CD7D: 2A 80 ; .2222... CD7F: 80 20 ; 2....2.. CD81: 0A ; 10 tiles StrCopyright2: ; .......2..22..2..2..22...22...22................................................ ; .......2.2....2.22.2..2.2..2.2..2......22...2..2...222...2...222..2..22......... ; .......2.2....2..2..222..22....2.......2.2.2.2.2...2.....2...2...2.2.2.2........ ; .......2..22..2..2....2.2..2..2........2.2.222.2...22....2...22..222.22......... ; ........2....2..222.22...22..2222......22..2.2.222.222...222.222.2.2.2.2........ ; .........2222................................................................... ; ........................................22222.22..2..2.222..2.2................. ; 2...2..22.222.2..2..22.222.22...222..2....2..2..2.22.2.2..2.2.2...22..2..22..22. ; CD82: 00 02 ; .......2 CD84: 00 02 ; .......2 CD86: 00 02 ; .......2 CD88: 00 02 ; .......2 CD8A: 00 00 ; ........ CD8C: 00 00 ; ........ CD8E: 00 00 ; ........ CD90: 80 82 ; 2...2..2 ; CD92: 0A 08 ; ..22..2. CD94: 20 08 ; .2....2. CD96: 20 08 ; .2....2. CD98: 0A 08 ; ..22..2. CD9A: 80 20 ; 2....2.. CD9C: 2A 80 ; .2222... CD9E: 00 00 ; ........ CDA0: 8A 88 ; 2.222.2. ; CDA2: 20 A0 ; .2..22.. CDA4: A2 08 ; 22.2..2. CDA6: 20 A8 ; .2..222. CDA8: 20 08 ; .2....2. CDAA: A8 A0 ; 222.22.. CDAC: 00 00 ; ........ CDAE: 00 00 ; ........ CDB0: 20 A2 ; .2..22.2 ; CDB2: 28 0A ; .22...22 CDB4: 82 20 ; 2..2.2.. CDB6: 28 02 ; .22....2 CDB8: 82 08 ; 2..2..2. CDBA: 28 2A ; .22..222 CDBC: 00 00 ; ........ CDBE: 00 00 ; ........ CDC0: A2 80 ; 22.22... ; CDC2: 00 00 ; ........ CDC4: 80 02 ; 2......2 CDC6: 00 02 ; .......2 CDC8: 00 02 ; .......2 CDCA: 80 02 ; 2......2 CDCC: 00 00 ; ........ CDCE: 00 00 ; ........ CDD0: A8 20 ; 222..2.. ; CDD2: 00 00 ; ........ CDD4: 80 82 ; 2...2..2 CDD6: 22 22 ; .2.2.2.2 CDD8: 22 A2 ; .2.222.2 CDDA: 82 22 ; 2..2.2.2 CDDC: 00 00 ; ........ CDDE: AA 8A ; 22222.22 CDE0: 08 20 ; ..2..2.. ; CDE2: 00 00 ; ........ CDE4: 02 A0 ; ...222.. CDE6: 02 00 ; ...2.... CDE8: 02 80 ; ...22... CDEA: A2 A0 ; 22.222.. CDEC: 00 00 ; ........ CDEE: 08 22 ; ..2..2.2 CDF0: 8A 22 ; 2.22.2.2 ; CDF2: 00 00 ; ........ CDF4: 20 2A ; .2...222 CDF6: 20 20 ; .2...2.. CDF8: 20 28 ; .2...22. CDFA: 2A 2A ; .222.222 CDFC: 00 00 ; ........ CDFE: A0 88 ; 22..2.2. CE00: 08 88 ; ..2.2.2. ; CE02: 00 00 ; ........ CE04: 08 28 ; ..2..22. CE06: 22 22 ; .2.2.2.2 CE08: 2A 28 ; .222.22. CE0A: 22 22 ; .2.2.2.2 CE0C: 00 00 ; ........ CE0E: 00 00 ; ........ CE10: 0A 08 ; ..22..2. ; CE12: 00 00 ; ........ CE14: 00 00 ; ........ CE16: 00 00 ; ........ CE18: 00 00 ; ........ CE1A: 00 00 ; ........ CE1C: 00 00 ; ........ CE1E: 00 00 ; ........ CE20: 28 28 ; .22..22. CE22: 0A StrCopyright3: ; 2...2.2...2...22.2.2...2...2.2...2..2.2...2..2..2.22.2.2..2.222..2...2.2.2.2.2.2 ; 2...2.2...22..2.22..22.22..2.2...2..2.2...2..2222.2.22.2..2..2...2...2.2.22..22. ; 222.2..22.222.2..2.22..222.22....2...2....2..2..2.2.22.222...2....22..2..2.2.2.. ; ................................................................................ ; .......2..2...2.....22..2..22.2.2.222..22...22..222..22.222.22..2.2.222.22...... ; ......2.2.2...2.....2.2.2.2...2.2..2..2.....2.2.2...2...2...2.2.2.2.2...2.2..... ; ......222.2...2.....22..2.2.2.222..2...22...22..22...22.22..22..2.2.22..2.2..... ; ......2.2.222.222...2.2.2..22.2.2..2..22....2.2.222.22..222.2.2..2..222.22...... ; CE23: 80 88 ; 2...2.2. CE25: 80 88 ; 2...2.2. CE27: A8 82 ; 222.2..2 CE29: 00 00 ; ........ CE2B: 00 02 ; .......2 CE2D: 00 08 ; ......2. CE2F: 00 0A ; ......22 CE31: 00 08 ; ......2. ; CE33: 08 0A ; ..2...22 CE35: 0A 08 ; ..22..2. CE37: 8A 88 ; 2.222.2. CE39: 00 00 ; ........ CE3B: 08 08 ; ..2...2. CE3D: 88 08 ; 2.2...2. CE3F: 88 08 ; 2.2...2. CE41: 8A 8A ; 2.222.22 ; CE43: 22 02 ; .2.2...2 CE45: A0 A2 ; 22..22.2 CE47: 22 82 ; .2.22..2 CE49: 00 00 ; ........ CE4B: 00 A0 ; ....22.. CE4D: 00 88 ; ....2.2. CE4F: 00 A0 ; ....22.. CE51: 80 88 ; 2...2.2. ; CE53: 02 20 ; ...2.2.. CE55: 82 20 ; 2..2.2.. CE57: A2 80 ; 22.22... CE59: 00 00 ; ........ CE5B: 82 88 ; 2..22.2. CE5D: 88 08 ; 2.2...2. CE5F: 88 8A ; 2.2.2.22 CE61: 82 88 ; 2..22.2. ; CE63: 20 88 ; .2..2.2. CE65: 20 88 ; .2..2.2. CE67: 20 20 ; .2...2.. CE69: 00 00 ; ........ CE6B: 8A 82 ; 2.222..2 CE6D: 82 08 ; 2..2..2. CE6F: 82 02 ; 2..2...2 CE71: 82 0A ; 2..2..22 ; CE73: 08 20 ; ..2..2.. CE75: 08 2A ; ..2..222 CE77: 08 20 ; ..2..2.. CE79: 00 00 ; ........ CE7B: 80 A0 ; 2...22.. CE7D: 00 88 ; ....2.2. CE7F: 80 A0 ; 2...22.. CE81: 00 88 ; ....2.2. ; CE83: 8A 22 ; 2.22.2.2 CE85: 88 A2 ; 2.2.22.2 CE87: 88 A2 ; 2.2.22.2 CE89: 00 00 ; ........ CE8B: A8 28 ; 222..22. CE8D: 80 80 ; 2...2... CE8F: A0 28 ; 22...22. CE91: A8 A0 ; 222.22.. ; CE93: 08 A8 ; ..2.222. CE95: 08 20 ; ..2..2.. CE97: A0 20 ; 22...2.. CE99: 00 00 ; ........ CE9B: A8 A0 ; 222.22.. CE9D: 80 88 ; 2...2.2. CE9F: A0 A0 ; 22..22.. CEA1: A8 88 ; 222.2.2. ; CEA3: 20 22 ; .2...2.2 CEA5: 20 22 ; .2...2.2 CEA7: 0A 08 ; ..22..2. CEA9: 00 00 ; ........ CEAB: 88 A8 ; 2.2.222. CEAD: 88 80 ; 2.2.2... CEAF: 88 A0 ; 2.2.22.. CEB1: 20 A8 ; .2..222. ; CEB3: 22 22 ; .2.2.2.2 CEB5: 28 28 ; .22..22. CEB7: 22 20 ; .2.2.2.. CEB9: 00 00 ; ........ CEBB: A0 00 ; 22...... CEBD: 88 00 ; 2.2..... CEBF: 88 00 ; 2.2..... CEC1: A0 00 ; 22......
The Cursive Doubleback Text
; Cursive "doubleback" data. Each 2 bytes holds 5 directional data points. ; The upper bit is unused. CEC3: 6D B6 ; 0 110 110 110 110 110 W W W W W CEC5: 27 6D ; 0 010 011 101 101 101 SW SW SW SE E CEC7: 12 52 ; 0 001 001 001 010 010 E E NE NE NE CEC9: 12 49 ; 0 001 001 001 001 001 NE NE NE NE NE CECB: 5A 49 ; 0 101 101 001 001 001 NE NE NE SW SW CECD: 5B 6D ; 0 101 101 101 101 101 SW SW SW SW SW CECF: 29 25 ; 0 010 100 100 100 101 SW S S S E CED1: 12 4A ; 0 001 001 001 001 010 E NE NE NE NE CED3: 5D 92 ; 0 101 110 110 010 010 E E W W SW CED5: 24 E5 ; 0 010 010 011 100 101 SW S SE E E CED7: 30 09 ; 0 011 000 000 001 001 NE NE N N SE CED9: 52 53 ; 0 101 001 001 010 011 SE E NE NE SW CEDB: 24 E5 ; 0 010 010 011 100 101 SW S SE E E CEDD: 52 49 ; 0 101 001 001 001 001 NE NE NE NE SW CEDF: 24 ED ; 0 010 010 011 101 101 SW SW SE E E CEE1: 12 52 ; 0 001 001 001 010 010 E E NE NE NE CEE3: 10 49 ; 0 001 000 001 001 001 NE NE NE N NE CEE5: 5C 00 ; 0 101 110 000 000 000 N N N W SW CEE7: 4B 2D ; 0 100 101 100 101 101 SW SW S SW S CEE9: 39 25 ; 0 011 100 100 100 101 SW S S S SE CEEB: 70 52 ; 0 111 000 001 010 010 E E NE N NW CEED: 24 93 ; 0 010 010 010 010 011 SE E E E E CEEF: 02 49 ; 0 000 001 001 001 001 NE NE NE NE N CEF1: 60 01 ; 0 110 000 000 000 001 NE N N N W CEF3: 59 6D ; 0 101 100 101 101 101 SW SW SW S SW CEF5: 49 2C ; 0 100 100 100 101 100 S SW S S S CEF7: 24 93 ; 0 010 010 010 010 011 SE E E E E CEF9: 02 4A ; 0 000 001 001 001 010 E NE NE NE N CEFB: 49 76 ; 0 100 100 101 110 110 W W SW S S CEFD: 24 93 ; 0 010 010 010 010 011 SE E E E E CEFF: 12 92 ; 0 001 001 010 010 010 E E E NE NE CF01: 02 49 ; 0 000 001 001 001 001 NE NE NE NE N CF03: 60 01 ; 0 110 000 000 000 001 NE N N N W CF05: 59 6D ; 0 101 100 101 101 101 SW SW SW S SW CF07: 49 2C ; 0 100 100 100 101 100 S SW S S S CF09: 02 93 ; 0 000 001 010 010 011 SE E E NE N CF0B: 14 9F ; 0 001 010 010 011 111 NW SE E E NE CF0D: 64 8A ; 0 110 010 010 001 010 E NE E E W CF0F: 39 6E ; 0 011 100 101 101 110 W SW SW S SE CF11: 40 4A ; 0 100 000 001 001 010 E NE NE N S CF13: 14 9D ; 0 001 010 010 011 101 SW SE E E NE CF15: 24 49 ; 0 010 010 001 001 001 NE NE NE E E CF17: 6D DA ; 0 110 110 111 011 010 E SE NW W W CF19: 39 2E ; 0 011 100 100 101 110 W SW S S SE CF1B: 24 92 ; 0 010 010 010 010 010 E E E E E CF1D: 12 49 ; 0 001 001 001 001 001 NE NE NE NE NE CF1F: 00 41 ; 0 000 000 001 000 001 NE N NE N N CF21: 5B 70 ; 0 101 101 101 110 000 N W SW SW SW CF23: 4B 2C ; 0 100 101 100 101 100 S SW S SW S CF25: 24 4C ; 0 010 010 001 001 100 S NE NE E E CF27: 37 AB ; 0 011 011 110 101 011 SE SW W SE SE CF29: 12 52 ; 0 001 001 001 010 010 E E NE NE NE CF2B: 00 00 ; END DirTable: ; These are X/Y offsets for each 8 directions CF2D: 00 FF ; 0 N CF2F: 01 FF ; 1 NE CF31: 01 00 ; 2 E CF33: 01 01 ; 3 SE CF35: 00 01 ; 4 S CF37: FF 01 ; 5 SW CF39: FF 00 ; 6 W CF3B: FF FF ; 7 NW
Songs
MusicFirstLife: CF3D: 28 80 CF3F: 40 40 CF41: 28 80 CF43: 40 40 CF45: 28 80 CF47: 40 40 CF49: 28 80 CF4B: 40 40 CF4D: 19 5F CF4F: 19 64 CF51: 19 5F CF53: 1A 55 CF55: 1C 4B CF57: 1C 55 CF59: 1C 4B CF5B: 1C 43 CF5D: 40 40 CF5F: 00 00 MusicSecondLife: CF61: 28 80 CF63: 40 40 CF65: 40 43 CF67: 40 40 CF69: 37 5F CF6B: 37 4B CF6D: 37 55 CF6F: 37 4B CF71: 19 5F CF73: 19 64 CF75: 19 5F CF77: 1A 55 CF79: 1C 4B CF7B: 1C 55 CF7D: 1C 4B CF7F: 1C 43 CF81: 40 40 CF83: 00 00 MusicThirdLife: CF85: 28 80 CF87: 40 40 CF89: 40 43 CF8B: 3C 4B CF8D: 39 55 CF8F: 37 5F CF91: 37 64 CF93: 37 5F CF95: 39 55 CF97: 3C 4B CF99: 40 43 CF9B: 39 55 CF9D: 40 40 CF9F: 00 00 CFA1: 14 1E CFA3: 00 00 MusicEndOfLife: ; Just one long note CFA5: FF FF CFA7: 00 00 ScoreTable: ; A zero is added to the end of all scores CFA9: 00 ; End marker CFAA: 07 ; Type 1: Apple 70 CFAB: 0A ; Type 2: Cherry 100 CFAC: 0F ; Type 3: Magnet 150 CFAD: 14 ; Type 4: Skate 200 CFAE: 19 ; Type 5: YoYo 250 CFAF: 1E ; Type 6: Pear 300 CFB0: 32 ; Type 7: Spider 500 CFB1: 00 ; Type 8: Skull (no score) CFB2: 64 ; Type 9: X 1000 ; ASCII version of the copyright (never used by the code) ; "COPYRIGHT 1982 DALE A. LEAR ALL RIGHTS RESERVED LICENSED TO TANDY COPRPORATION" CFB3: 43 4F 50 59 52 49 47 48 54 20 31 39 38 32 20 44 41 4C 45 20 41 2E 20 4C 45 41 52 20 41 4C 4C 20 CFD3: 52 49 47 48 54 53 20 52 45 53 45 52 56 45 44 20 4C 49 43 45 4E 53 45 44 20 54 4F 20 54 41 4E 44 CFF3: 59 20 43 4F 52 50 4F 52 41 54 49 4F 4E