ATARI 800 CHECKERS DISPLAY BY C. SHAW 3/31/80 ; Copyright 1980 Atari, Inc. and Carol Shaw#

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Source Code#

10  .TITLE "ATARI 800 CHECKERS DISPLAY BY C. SHAW 3/31/80"
20 ;
30 ;COPYRIGHT ATARI 1980
40 ;
50 ;THIS IS AN EXAMPLE OF A DISPLAY LIST WHICH USES CHARACTER MAPPING TO
60 ;PRODUCE THE CHECKERS AND THE TOP AND BOTTOM BORDERS OF THE BOARD.
70 ;PLAYERS ARE USED FOR THE RED SQUARES. THIS GIVES 6 COLORS WITHOUT
80 ;CHANGING THE COLOR REGISTERS.
90 ;MISSILES ARE USED FOR THE LEFT AND RIGHT BORDERS.
0100 ;THE PROGRAM STARTS AT THE LOCATION SPECIFIED BY PMB.
0110 ;A FEW TRICKS ARE USED TO SAVE RAM, BUT FURTHER OPTIMIZATION IS POSSIBLE
0120 ;ROM CARTRIDGE.
0140 ;
0150 ;COLLEEN (ATARI 800) EQUATES
0160 ;
0170 CHBASE =    $D409
0180 DMACTL =    $D400
0190 SDMCTL =    $022F
0200 HPOSP0 =    $D000
0210 SIZEP0 =    $D008
0220 PCOLR0 =    $02C0
0230 SDLSTL =    $0230
0240 SDLSTH =    $0231
0250 GRACTL =    $D01D
0260 PMBASE =    $D407
0270 GPRIOR =    $026F
0280 VDSLST =    $0200
0290 NMIEN  =    $D40E
0300 ;
0310 ;DISPLAY LIST EQUATES
0320 ;
0330 INT    =    $80   ;DISPLAY LIST INTERRUPT (BIT 7 OF NMI STATUS)
0340 JMPWT  =    $41   ;JUMP AND WAIT UNTIL END OF NEXT VERTICAL BLANK (2 BYTES)
0350 RELOAD =    $40   ;RELOAD MEM SCAN COUNTER (2 BYTES)
0360 VSC    =    $20   ;VERTICAL SCROLL ENABLE
0370 HSC    =    $10   ;HORIZONTAL SCROLL ENABLE
0380 JUMP   =    1     ;JUMP INSTRUCTION (2 BYTES)
0390 BLANK1 =    0     ;1 BLANK TV LINE
0400 BLANK2 =    $10   ;2 BLANK LINES
0410 BLANK3 =    $20   ;3
0420 BLANK4 =    $30   ;4
0430 BLANK5 =    $40   ;5
0440 BLANK6 =    $50   ;6
0450 BLANK7 =    $60   ;7
0460 BLANK8 =    $70   ;8 BLANK TV LINES
0470  .PAGE
0480 ;
0490 INTOFF =    $20       ;USED TO GET INTERNAL CODE FOR UPPER CASE ALPHANUMERICS
0500 ;
0510 ;INTERNAL CHARACTER CODES
0520 ;
0530 SPI    =    ' -INTOFF
0540 AI     =    'A-INTOFF
0550 CI     =    'C-INTOFF
0560 DI     =    'D-INTOFF
0570 EI     =    'E-INTOFF
0580 GI     =    'G-INTOFF
0590 HI     =    'H-INTOFF
0600 II     =    'I-INTOFF
0610 OI     =    'O-INTOFF
0620 PI     =    'P-INTOFF
0630 RI     =    'R-INTOFF
0640 TI     =    'T-INTOFF
0650 YI     =    'Y-INTOFF
0660 N1I    =    '1-INTOFF
0670 N8I    =    '8-INTOFF
0680 N9I    =    '9-INTOFF
0690 N0I    =    '0-INTOFF
0700 ;
0710 ;CHECKERS EQUATES
0720 ;
0730 ;CODES FOR SPECIAL CHECKERS CHARACTER SET
0740 ;
0750 EMPTY  =    0      ;EMPTY SQUARE
0760 CHECKER=    1      ;ORDINARY CHECKER
0770 KING   =    2
0780 CURS   =    3      ;CURSOR (X)
0790 BORDER =    4      ;USED FOR TOP AND BOTTOM BORDERS OF BOARD
0800 ;
0810 CLP0   =    0      ;PLAYER 0 (HUMAN)
0820 CLP1   =    $80        ;PLAYER 1 (COMPUTER)
0830 CLBOR  =    $C0        ;BORDER COLOR (USED TO SET UP 2 MSB'S OF CHAR)
0840 PMB    =    $5000  ;PLAYER MISSILE BASE ADDRESS & PROGRAM LOCATION
0850  .PAGE
0860 ;
0870 ; RAM VARIABLES
0880 ;
0890        *=  PMB
0900 BOARD  *=  *+32        ;CHECKER BOARD (ONLY 32 BLOCK SQUARES ARE USED)
0910 T0     *=  *+1         ;TEMP FOR MOVING BOARD TO MEM MAP
0920 ;
0930 ;PLAYER AND MISSILE GRAPHICS.
0940 ;PLAYERS ARE USED FOR SQUARES, MISSILES FOR LEFT AND RIGHT BORDERS.
0950 ;
0960        *=   PMB+$180
0970 GRM03  *=   *+$80     ;MISSILE GRAPHICS
0980 GRP0   *=   *+$80     ;PLAYER 0 GRAPHICS
0990 GRP1   *=   *+$80     ;PLAYER 1
1000 GRP2   *=   *+$80     ;       2
1010 GRP3   *=   *+$80     ;       3
1020 ;
1030 TITL   *=   *+20      ;TOP LINE OF CHARS -- ATASCII MESSAGE
1040 TOPBRD *=   *+16      ;TOP BORDER OF BOARD
1050 BRDSP  *=   8*16+*    ;BOARD DISPLAY
1060 BOTBRD *=   *+16      ;BOTTOM BORDER
1070  .PAGE
1080 ;
1090 ;GP -- SPECIAL CHECKERS CHARACTER SET (ONLY CODES 0-4 ARE USED).
1100 ;
1110        *=   PMB+$600
1120 GR
1130        .BYTE 0,0,0,0,0,0,0,0 ; BLANK (0)
1140        .BYTE $3C,$7E,$FF,$FF,$FF,$FF,$7E,$3C ;CHECKER (1)
1150        .BYTE $3C,$7E,$A5,$A5,$C3,$C3,$7E,$3C ;KING (2)
1160        .BYTE $C3,$66,$3C,$18,$18,$3C,$66,$C3 ;CURSOR (3)
1170        .BYTE 0,$FF,$FF,$FF,$FF,$FF,$FF,0 ;BORDER (4)
1180  .PAGE
1190 ;
1200 ;
1210 ;DISPLAY LIST
1220 ;
1230 DSP
1240        .BYTE BLANK8 ;24 BLANK LINES
1250        .BYTE BLANK8
1260        .BYTE BLANK8
1270        .BYTE RELOAD+6 ;LINES 0-7 MESSAGE LINE: 20 ACROSS X 5 COLOR X 1 LINE RESOLUTION CHARACTERS
1280        .WORD TITL
1290        .BYTE INT+BLANK1 ;8. INTERRUPT TO CHANGE CHARACTER BASE ADDRESS AND CHANGE TO NARROW SCREEN.
1300        .BYTE 6        ;9-16. TOP BORDER: 16 X 5 X 1 CHARS (LAST LINE IS TOP OF 1ST ROW OF SQUARES)
1310        .BYTE BLANK2   ;17-18. TOP OF FIRST ROW OF SQUARES
1320 ;                     CHECKERBOARD (8 LINES OF CHARS WITH SPACES INBETWEEN - 22 LINES/SQUARE)
1330        .BYTE 7        ;19-34. 16X5X2 LINE RESOLUTION CHARS
1340        .BYTE BLANK6   ;35-40. FIRST 3 LINES=BOTTOM OF PREVIOUS SQUARE.
1350        .BYTE 7        ;41-56
1360        .BYTE BLANK6   ;57-62. LAST 3 LINES=TOP OF NEXT SQUARE.
1370        .BYTE 7        ;63-78
1380        .BYTE BLANK6   ;79-84
1390        .BYTE 7        ;85-100
1400        .BYTE BLANK6   ;101-106
1410        .BYTE 7        ;107-122
1420        .BYTE BLANK6   ;123-128
1430        .BYTE 7        ;129-144
1440        .BYTE BLANK6   ;145-150
1450        .BYTE 7        ;151-166
1460        .BYTE BLANK6   ;167-172
1470        .BYTE 7        ;173-188
1480 ;                      NEXT THREE LINES ARE BOTTOM OF PREVIOUS SQUARE
1490        .BYTE BLANK2   ;189-190. END OF NORMAL DISPLAY (SHOULD BE ON SCREEN ON ALL TV'S).
1500        .BYTE 6        ;191-198. BOTTOM BORDER (MAY OVERSCAN, BUT NOT ESSENTIAL TO GAME PLAY)
1510        .BYTE JMPWT    ;WAIT FOR NEXT VBLANK, THEN START OVER
1520        .WORD DSP
1530 ;
1540 ;
1550 ;DSP -- DISPLAY LIST INTERRUPT HANDLER.
1560 ;CHANGES CHARACTER BASE AND WIDTH OF DISPLAY FOR SPECIAL CHECKERS GRAPHICS
1570 ;THE OS WILL CHANGE CHBASE BACK TO NORMAL DURING VERTICAL BLANK.
1580 ;
1590 NCHR
1600        PHA
1610        LDA  #GR/256
1620        STA  CHBASE
1630 ;
1640 ;INSTRUCTION FETCH DMA ENABLE, P/M 2 LINE RES, P/M DMA ENABLE, NARROW SCREEN (128 CLOCKS)
1650        LDA  #$2D
1660        STA  DMACTL
1670        PLA
1680        RTI
1690  .PAGE
1700 ;
1710 ;INITIALIZATION CODE -- START EXECUTION HERE
1720 ;
1730        *=   PMB+$700
1740 ;
1750 ;INIT OS'S DMACTL VRRIRBLE
1760 ;INSTRUCTION FETCH DMA ENABLE, P/M 2 LINE RES, P/M DMA ENABLE, STANDARD SCREEN (160 CLOCKS)
1770 ;
1780        LDA  #$2E
1790        STA  SDMCTL
1800 ;
1810 ;CLEAR RAM
1820 ;
1830        LDA  #0
1840        TAX
1850 INITLP
1860        STA  PMB,X
1870        STA  PMB+$100,X
1880        STA  PMB+$200,X
1890        STA  PMB+$300,X
1900        STA  PMB+$400,X
1910        INX
1920        BNE  INITLP
1930 ;
1940 ;INITIALIZE MISSILE GRAPHICS FOR BORDERS
1950 ;
1960        LDA  #$0E
1970        LDY  #$5E
1980 LQPZ   STA  GRM03+$14,Y
1990        DEY
2000        BNE  LQPZ
2010 ;
2020 ;INITIALIZE TOP AND BOTTOM BORDERS.
2030 ;
2040        LDY  #16
2050        LDA  #CLBOR+BORDER
2060 TBLP   STA  TOPBRD-1,Y
2070        STA  BOTBRD-1,Y
2080        DEY
2090        BNE  TBLP ; CONTINUE UNTIL Y=0
2100 ;
2110 ;INITIALIZE PLAYER GRAPHICS FOR SQUARES (CHECKER BOARD) Y=0
2120 ;
2130        LDA  #$F0
2140 IN2    LDX  #10
2150 IN3    STA  GRP0+$18,Y
2160        STA  GRP1+$18,Y
2170        STA  GRP2+$18,Y
2180        STA  GRP3+$18,Y
2190 ;
2200        PHA
2210        LDA  #$0A
2220        STA  GRM03+$18,Y ;REST OF MISSILE GRAPHICS
2230        PLA
2240        INY
2250        DEX
2260        BPL  IN3
2270        EOR  #$FF      ;FILL IN OPPOSITE SQUARES
2280        CPY  #88
2290        BCC  IN2
2300        LDY  #8
2310 ;
2320 ; INITIALIZE PLAYER AND MISSILE POSITIONS AND COLORS
2330 ;
2340 IN4    LDA  ITBL,Y
2350        STA  HPOSP0,Y
2360        TXA           ;$FF
2370        STA  SIZEP0,Y ;$03 INDICATES 4 TIMES NORMAL SIZE (REST IS DON'T CARE)
2380        LDA  ITBL1,Y
2390        STA  PCOLR0,Y
2400        DEY
2410        BPL  IN4
2420 ;
2430 ;OS, ANTIC, POKEY INITIALIZATION
2440 ;
2450        LDA  #DSP&$FF  ; DISPLAY LIST START ADDRESS (LSB)
2460        STA  SDLSTL
2470        LDA  #DSP/256  ; MSB OF ADDRESS
2480        STA  SDLSTH
2490        LDA  #3        ;ENABLE PLAYER/MISSILE DMA TO GRAPHICS REGS.
2500        STA  GRACTL
2510        LDA  #PMB/256  ;MSB OF ADDRESS OF PLAYER/MISSILE GRAPHICS
2520        STA  PMBASE
2530        LDA  #$14      ;5TH PLAYER ENABLE (USE PF3 FOR MISSILE COLOR), PF TAKES PRIO OVER PLAYERS
2540        STA  GPRIOR    ;OS PRIORITY REG
2550        LDA  #NCHR&$FF ;DISPLAY LIST INTERRUPT VECTOR (LSB)
2560        STA  VDSLST
2570        LDA  #NCHR/256
2580        STA  VDSLST+1
2590        STX  NMIEN     ;X=$FF   $C0 ENABLES DISPLAY LIST & VBLANK INTERRUPTS.
2600 ;
2610 ;INITIALIZE BOARD DISPLAY
2620 ;
2630        LDX  #11
2640 BRDLP
2650        LDA  #CHECKER+CLP0 ;HUMAN PIECES ON SQUARES 0-11
2660        STA  BOARD,X
2670        LDA  #CHECKER+CLP1 ;COMPUTER PIECES ON SQUARES 20-31
2680        STA  BOARD+20,X
2690        DEX
2700        BPL  BRDLP
2710 ;
2720 ;MOVE COPYRIGHT MESSAGE TO MESSAGE DISPLAY LINE
2730 ;
2740        LDX  #19
2750 IN6    LDA  COPY,X
2760        STA  TITL,X
2770        DEX
2780        BPL  IN6
2790 ;
2800 ;LOOP TO MOVE BOARD TO GRAPHICS AREA.
2810 ;THE CHECKERS PROGRAM LOGIC COULD BE ADDED HERE OR A VBLANK INTERRUPT COULD BE USED.
2820 ;
2830 LOOP
2840        JSR  UPCHR
2850        JMP  LOOP
2860 ;
2870 ;
2880 ;
2890 ;
2900 ;UPCHR -- SUBROUTINE TO MOVE 32 BYTES OF CHECKER BOARD TO DISPLAY RAM.
2910 ;
2920 UPCHR
2930        LDX  #31       ;SQUARE 31 = UPPER LEFT
2940        LDY  #0
2950 UPLP1
2960        LDA  #4-1      ;4 SQUARES/LINE
2970        STA  T0
2980 UPLP2
2990        LDA  BOARD,X
3000        STA  BRDSP+2,Y ; FOR ROWS SHIFTED TO RIGHT
3010        LDA  BOARD-4,X
3020        STA  BRDSP+$10,Y ; FOR ROWS SHIFTED TO LEFT
3030        INY
3040        INY
3050        INY
3060        INY
3070        DEX
3080        DEC  T0
3090        BPL  UPLP2
3100 ;
3110        TYA
3120        CLC
3130        ADC  #$10
3140        TAY
3150        TXA
3160        SBC  #4-1      ;CARRY IS CLEAR (SUBTRACT 4)
3170        TAX
3180        BCS  UPLP1
3190        RTS
3200 ;
3210 ;
3220 ;
3230 ;
3240 ;DATA
3250 ;HORIZONTAL POSITION OF PLAYERS (SQUARES) AND MISSILES (SIDE BORDERS).
3260 ;M0=RIGHT BORDER, M1=LEFT BORDER
3270 ;M2 & M3 ARE PLACED WITH M1.
3280 ;             P0, P1, P2, P3, M0, M1, M2, M2
3290 ITBL
3300        .BYTE $3C,$5C,$7C,$9C,$BC,$38,$38,$38
3310 ;
3320 ;COLOR TABLE
3330 ITBL1
3340        .BYTE $34,$34,$34,$34 ;4 PLAYERS (RED SQUARES)
3350        .BYTE $36      ;PF0 RED CHECKERS AND MESSAGES
3360        .BYTE $88      ;PF1 BLUE CHARACTERS
3370        .BYTE $0E      ;PF2 WHITE CHECKERS AND MESSAGES
3380        .BYTE $26      ;PF3 YELLOW BORDER (CHARS & MISSILES)
3390        .BYTE 0        ;BK: BLACK BACKGROUND
3400 ;
3410 ;"COPYRIGHT ATARI 1980" MESSAGE
3420 ;
3430 OF     =    $00       ;FOR PF0 COLOR (RED)
3440 OF2    =    $80       ;FOR PF2 COLOR (WHITE)
3450 OF3    =    $40       ;FOR PF1 COLOR (BLUE)
3460 TGTBL
3470 COPY   .BYTE SPI,CI+OF,OI+OF,PI+OF,YI+OF,RI+OF,II+OF,GI+OF,HI+OF,TI+OF
3480        .BYTE AI+OF2,TI+OF2,AI+OF2,RI+OF2,II+OF2,N1I+OF3,N9I+OF3,N8I+OF3,N0I+OF3

Assembled Source Code with 0 errors#


0000        10          .TITLE "ATARI 800 CHECKERS DISPLAY BY C. SHAW 3/31/80"
            20 ;
            30 ;COPYRIGHT ATARI 1980
            40 ;
            50 ;THIS IS AN EXAMPLE OF A DISPLAY LIST WHICH USES CHARACTER MAPPING TO
            60 ;PRODUCE THE CHECKERS AND THE TOP AND BOTTOM BORDERS OF THE BOARD.
            70 ;PLAYERS ARE USED FOR THE RED SQUARES. THIS GIVES 6 COLORS WITHOUT
            80 ;CHANGING THE COLOR REGISTERS.
            90 ;MISSILES ARE USED FOR THE LEFT AND RIGHT BORDERS.
            0100 ;THE PROGRAM STARTS AT THE LOCATION SPECIFIED BY PMB.
            0110 ;A FEW TRICKS ARE USED TO SAVE RAM, BUT FURTHER OPTIMIZATION IS POSSIBLE
            0120 ;ROM CARTRIDGE.
            0140 ;
            0150 ;COLLEEN (ATARI 800) EQUATES
            0160 ;
D409        0170 CHBASE =    $D409     
D400        0180 DMACTL =    $D400     
022F        0190 SDMCTL =    $022F     
D000        0200 HPOSP0 =    $D000     
D008        0210 SIZEP0 =    $D008     
02C0        0220 PCOLR0 =    $02C0     
0230        0230 SDLSTL =    $0230     
0231        0240 SDLSTH =    $0231     
D01D        0250 GRACTL =    $D01D     
D407        0260 PMBASE =    $D407     
026F        0270 GPRIOR =    $026F     
0200        0280 VDSLST =    $0200     
D40E        0290 NMIEN  =    $D40E     
            0300 ;
            0310 ;DISPLAY LIST EQUATES
            0320 ;
0080        0330 INT    =    $80       ;DISPLAY LIST INTERRUPT (BIT 7 OF NMI STATUS)
0041        0340 JMPWT  =    $41       ;JUMP AND WAIT UNTIL END OF NEXT VERTICAL BLANK (2 BYTES)
0040        0350 RELOAD =    $40       ;RELOAD MEM SCAN COUNTER (2 BYTES)
0020        0360 VSC    =    $20       ;VERTICAL SCROLL ENABLE
0010        0370 HSC    =    $10       ;HORIZONTAL SCROLL ENABLE
0001        0380 JUMP   =    1         ;JUMP INSTRUCTION (2 BYTES)
0000        0390 BLANK1 =    0         ;1 BLANK TV LINE
0010        0400 BLANK2 =    $10       ;2 BLANK LINES
0020        0410 BLANK3 =    $20       ;3
0030        0420 BLANK4 =    $30       ;4
0040        0430 BLANK5 =    $40       ;5
0050        0440 BLANK6 =    $50       ;6
0060        0450 BLANK7 =    $60       ;7
0070        0460 BLANK8 =    $70       ;8 BLANK TV LINES


ATARI 800 CHECKERS DISPLAY BY C. SHAW 3/31/80
 

0000        0470        .PAGE          
            0480 ;
0020        0490 INTOFF =    $20       ;USED TO GET INTERNAL CODE FOR UPPER CASE ALPHANUMERICS
            0500 ;
            0510 ;INTERNAL CHARACTER CODES
            0520 ;
0000        0530 SPI    =    ' -INTOFF 
0021        0540 AI     =    'A-INTOFF 
0023        0550 CI     =    'C-INTOFF 
0024        0560 DI     =    'D-INTOFF 
0025        0570 EI     =    'E-INTOFF 
0027        0580 GI     =    'G-INTOFF 
0028        0590 HI     =    'H-INTOFF 
0029        0600 II     =    'I-INTOFF 
002F        0610 OI     =    'O-INTOFF 
0030        0620 PI     =    'P-INTOFF 
0032        0630 RI     =    'R-INTOFF 
0034        0640 TI     =    'T-INTOFF 
0039        0650 YI     =    'Y-INTOFF 
0011        0660 N1I    =    '1-INTOFF 
0018        0670 N8I    =    '8-INTOFF 
0019        0680 N9I    =    '9-INTOFF 
0010        0690 N0I    =    '0-INTOFF 
            0700 ;
            0710 ;CHECKERS EQUATES
            0720 ;
            0730 ;CODES FOR SPECIAL CHECKERS CHARACTER SET
            0740 ;
0000        0750 EMPTY  =    0         ;EMPTY SQUARE
0001        0760 CHECKER=    1         ;ORDINARY CHECKER
0002        0770 KING   =    2         
0003        0780 CURS   =    3         ;CURSOR (X)
0004        0790 BORDER =    4         ;USED FOR TOP AND BOTTOM BORDERS OF BOARD
            0800 ;
0000        0810 CLP0   =    0         ;PLAYER 0 (HUMAN)
0080        0820 CLP1   =    $80        ;PLAYER 1 (COMPUTER)
00C0        0830 CLBOR  =    $C0        ;BORDER COLOR (USED TO SET UP 2 MSB'S OF CHAR)
5000        0840 PMB    =    $5000     ;PLAYER MISSILE BASE ADDRESS & PROGRAM LOCATION


ATARI 800 CHECKERS DISPLAY BY C. SHAW 3/31/80
 

0000        0850        .PAGE          
            0860 ;
            0870 ; RAM VARIABLES
            0880 ;
0000        0890        *=   PMB       
5000        0900 BOARD  *=   *+32        ;CHECKER BOARD (ONLY 32 BLOCK SQUARES ARE USED)
5020        0910 T0     *=   *+1         ;TEMP FOR MOVING BOARD TO MEM MAP
            0920 ;
            0930 ;PLAYER AND MISSILE GRAPHICS.
            0940 ;PLAYERS ARE USED FOR SQUARES, MISSILES FOR LEFT AND RIGHT BORDERS.
            0950 ;
5021        0960        *=   PMB+$180  
5180        0970 GRM03  *=   *+$80     ;MISSILE GRAPHICS
5200        0980 GRP0   *=   *+$80     ;PLAYER 0 GRAPHICS
5280        0990 GRP1   *=   *+$80     ;PLAYER 1
5300        1000 GRP2   *=   *+$80     ;       2
5380        1010 GRP3   *=   *+$80     ;       3
            1020 ;
5400        1030 TITL   *=   *+20      ;TOP LINE OF CHARS -- ATASCII MESSAGE
5414        1040 TOPBRD *=   *+16      ;TOP BORDER OF BOARD
5424        1050 BRDSP  *=   8*16+*    ;BOARD DISPLAY
54A4        1060 BOTBRD *=   *+16      ;BOTTOM BORDER


ATARI 800 CHECKERS DISPLAY BY C. SHAW 3/31/80
 

54B4        1070        .PAGE          
            1080 ;
            1090 ;GP -- SPECIAL CHECKERS CHARACTER SET (ONLY CODES 0-4 ARE USED).
            1100 ;
54B4        1110        *=   PMB+$600  
            1120 GR
5600 00     1130        .BYTE 0,0,0,0,0,0,0,0 ; BLANK (0)
5601 00
5602 00
5603 00
5604 00
5605 00
5606 00
5607 00
5608 3C     1140        .BYTE $3C,$7E,$FF,$FF,$FF,$FF,$7E,$3C ;CHECKER (1)
5609 7E
560A FF
560B FF
560C FF
560D FF
560E 7E
560F 3C
5610 3C     1150        .BYTE $3C,$7E,$A5,$A5,$C3,$C3,$7E,$3C ;KING (2)
5611 7E
5612 A5
5613 A5
5614 C3
5615 C3
5616 7E
5617 3C
5618 C3     1160        .BYTE $C3,$66,$3C,$18,$18,$3C,$66,$C3 ;CURSOR (3)
5619 66
561A 3C
561B 18
561C 18
561D 3C
561E 66
561F C3
5620 00     1170        .BYTE 0,$FF,$FF,$FF,$FF,$FF,$FF,0 ;BORDER (4)
5621 FF
5622 FF
5623 FF
5624 FF
5625 FF
5626 FF
5627 00


ATARI 800 CHECKERS DISPLAY BY C. SHAW 3/31/80


5628        1180        .PAGE          
            1190 ;
            1200 ;
            1210 ;DISPLAY LIST
            1220 ;
            1230 DSP
5628 70     1240        .BYTE BLANK8   ;24 BLANK LINES
5629 70     1250        .BYTE BLANK8   
562A 70     1260        .BYTE BLANK8   
562B 46     1270        .BYTE RELOAD+6 ;LINES 0-7 MESSAGE LINE: 20 ACROSS X 5 COLOR X 1 LINE RESOLUTION CHARACTERS
562C 0054   1280        .WORD TITL     
562E 80     1290        .BYTE INT+BLANK1 ;8. INTERRUPT TO CHANGE CHARACTER BASE ADDRESS AND CHANGE TO NARROW SCREEN.
562F 06     1300        .BYTE 6        ;9-16. TOP BORDER: 16 X 5 X 1 CHARS (LAST LINE IS TOP OF 1ST ROW OF SQUARES)
5630 10     1310        .BYTE BLANK2   ;17-18. TOP OF FIRST ROW OF SQUARES
            1320 ;                     CHECKERBOARD (8 LINES OF CHARS WITH SPACES INBETWEEN - 22 LINES/SQUARE)
5631 07     1330        .BYTE 7        ;19-34. 16X5X2 LINE RESOLUTION CHARS
5632 50     1340        .BYTE BLANK6   ;35-40. FIRST 3 LINES=BOTTOM OF PREVIOUS SQUARE.
5633 07     1350        .BYTE 7        ;41-56
5634 50     1360        .BYTE BLANK6   ;57-62. LAST 3 LINES=TOP OF NEXT SQUARE.
5635 07     1370        .BYTE 7        ;63-78
5636 50     1380        .BYTE BLANK6   ;79-84
5637 07     1390        .BYTE 7        ;85-100
5638 50     1400        .BYTE BLANK6   ;101-106
5639 07     1410        .BYTE 7        ;107-122
563A 50     1420        .BYTE BLANK6   ;123-128
563B 07     1430        .BYTE 7        ;129-144
563C 50     1440        .BYTE BLANK6   ;145-150
563D 07     1450        .BYTE 7        ;151-166
563E 50     1460        .BYTE BLANK6   ;167-172
563F 07     1470        .BYTE 7        ;173-188
            1480 ;                      NEXT THREE LINES ARE BOTTOM OF PREVIOUS SQUARE
5640 10     1490        .BYTE BLANK2   ;189-190. END OF NORMAL DISPLAY (SHOULD BE ON SCREEN ON ALL TV'S).
5641 06     1500        .BYTE 6        ;191-198. BOTTOM BORDER (MAY OVERSCAN, BUT NOT ESSENTIAL TO GAME PLAY)
5642 41     1510        .BYTE JMPWT    ;WAIT FOR NEXT VBLANK, THEN START OVER
5643 2856   1520        .WORD DSP      
            1530 ;
            1540 ;
            1550 ;DSP -- DISPLAY LIST INTERRUPT HANDLER.
            1560 ;CHANGES CHARACTER BASE AND WIDTH OF DISPLAY FOR SPECIAL CHECKERS GRAPHICS
            1570 ;THE OS WILL CHANGE CHBASE BACK TO NORMAL DURING VERTICAL BLANK.
            1580 ;
            1590 NCHR
5645 48     1600        PHA            
5646 A956   1610        LDA  #GR/256   
5648 8D09D4 1620        STA  CHBASE    
            1630 ;
            1640 ;INSTRUCTION FETCH DMA ENABLE, P/M 2 LINE RES, P/M DMA ENABLE, NARROW SCREEN (128 CLOCKS)
564B A92D   1650        LDA  #$2D      
564D 8D00D4 1660        STA  DMACTL    
5650 68     1670        PLA            
5651 40     1680        RTI            


ATARI 800 CHECKERS DISPLAY BY C. SHAW 3/31/80
 

5652        1690        .PAGE          
            1700 ;
            1710 ;INITIALIZATION CODE -- START EXECUTION HERE
            1720 ;
5652        1730        *=   PMB+$700  
            1740 ;
            1750 ;INIT OS'S DMACTL VRRIRBLE
            1760 ;INSTRUCTION FETCH DMA ENABLE, P/M 2 LINE RES, P/M DMA ENABLE, STANDARD SCREEN (160 CLOCKS)
            1770 ;
5700 A92E   1780        LDA  #$2E      
5702 8D2F02 1790        STA  SDMCTL    
            1800 ;
            1810 ;CLEAR RAM
            1820 ;
5705 A900   1830        LDA  #0        
5707 AA     1840        TAX            
            1850 INITLP
5708 9D0050 1860        STA  PMB,X     
570B 9D0051 1870        STA  PMB+$100,X
570E 9D0052 1880        STA  PMB+$200,X
5711 9D0053 1890        STA  PMB+$300,X
5714 9D0054 1900        STA  PMB+$400,X
5717 E8     1910        INX            
5718 D0EE   1920        BNE  INITLP    
            1930 ;
            1940 ;INITIALIZE MISSILE GRAPHICS FOR BORDERS
            1950 ;
571A A90E   1960        LDA  #$0E      
571C A05E   1970        LDY  #$5E      
571E 999451 1980 LQPZ   STA  GRM03+$14,Y
5721 88     1990        DEY            
5722 D0FA   2000        BNE  LQPZ      
            2010 ;
            2020 ;INITIALIZE TOP AND BOTTOM BORDERS.
            2030 ;
5724 A010   2040        LDY  #16       
5726 A9C4   2050        LDA  #CLBOR+BORDER
5728 991354 2060 TBLP   STA  TOPBRD-1,Y
572B 99A354 2070        STA  BOTBRD-1,Y
572E 88     2080        DEY            
572F D0F7   2090        BNE  TBLP      ; CONTINUE UNTIL Y=0
            2100 ;
            2110 ;INITIALIZE PLAYER GRAPHICS FOR SQUARES (CHECKER BOARD) Y=0
            2120 ;
5731 A9F0   2130        LDA  #$F0      
5733 A20A   2140 IN2    LDX  #10       
5735 991852 2150 IN3    STA  GRP0+$18,Y
5738 999852 2160        STA  GRP1+$18,Y
573B 991853 2170        STA  GRP2+$18,Y
573E 999853 2180        STA  GRP3+$18,Y
            2190 ;
5741 48     2200        PHA            
5742 A90A   2210        LDA  #$0A      
5744 999851 2220        STA  GRM03+$18,Y ;REST OF MISSILE GRAPHICS
5747 68     2230        PLA            
5748 C8     2240        INY            
5749 CA     2250        DEX            
574A 10E9   2260        BPL  IN3       
574C 49FF   2270        EOR  #$FF      ;FILL IN OPPOSITE SQUARES


ATARI 800 CHECKERS DISPLAY BY C. SHAW 3/31/80
 

574E C058   2280        CPY  #88       
5750 90E1   2290        BCC  IN2       
5752 A008   2300        LDY  #8        
            2310 ;
            2320 ; INITIALIZE PLAYER AND MISSILE POSITIONS AND COLORS
            2330 ;
5754 B9D857 2340 IN4    LDA  ITBL,Y    
5757 9900D0 2350        STA  HPOSP0,Y  
575A 8A     2360        TXA            ;$FF
575B 9908D0 2370        STA  SIZEP0,Y  ;$03 INDICATES 4 TIMES NORMAL SIZE (REST IS DON'T CARE)
575E B9E057 2380        LDA  ITBL1,Y   
5761 99C002 2390        STA  PCOLR0,Y  
5764 88     2400        DEY            
5765 10ED   2410        BPL  IN4       
            2420 ;
            2430 ;OS, ANTIC, POKEY INITIALIZATION
            2440 ;
5767 A928   2450        LDA  #DSP&$FF  ; DISPLAY LIST START ADDRESS (LSB)
5769 8D3002 2460        STA  SDLSTL    
576C A956   2470        LDA  #DSP/256  ; MSB OF ADDRESS
576E 8D3102 2480        STA  SDLSTH    
5771 A903   2490        LDA  #3        ;ENABLE PLAYER/MISSILE DMA TO GRAPHICS REGS.
5773 8D1DD0 2500        STA  GRACTL    
5776 A950   2510        LDA  #PMB/256  ;MSB OF ADDRESS OF PLAYER/MISSILE GRAPHICS
5778 8D07D4 2520        STA  PMBASE    
577B A914   2530        LDA  #$14      ;5TH PLAYER ENABLE (USE PF3 FOR MISSILE COLOR), PF TAKES PRIO OVER PLAYERS
577D 8D6F02 2540        STA  GPRIOR    ;OS PRIORITY REG
5780 A945   2550        LDA  #NCHR&$FF ;DISPLAY LIST INTERRUPT VECTOR (LSB)
5782 8D0002 2560        STA  VDSLST    
5785 A956   2570        LDA  #NCHR/256 
5787 8D0102 2580        STA  VDSLST+1  
578A 8E0ED4 2590        STX  NMIEN     ;X=$FF   $C0 ENABLES DISPLAY LIST & VBLANK INTERRUPTS.
            2600 ;
            2610 ;INITIALIZE BOARD DISPLAY
            2620 ;
578D A20B   2630        LDX  #11       
            2640 BRDLP
578F A901   2650        LDA  #CHECKER+CLP0 ;HUMAN PIECES ON SQUARES 0-11
5791 9D0050 2660        STA  BOARD,X   
5794 A981   2670        LDA  #CHECKER+CLP1 ;COMPUTER PIECES ON SQUARES 20-31
5796 9D1450 2680        STA  BOARD+20,X
5799 CA     2690        DEX            
579A 10F3   2700        BPL  BRDLP     
            2710 ;
            2720 ;MOVE COPYRIGHT MESSAGE TO MESSAGE DISPLAY LINE
            2730 ;
579C A213   2740        LDX  #19       
579E BDE957 2750 IN6    LDA  COPY,X    
57A1 9D0054 2760        STA  TITL,X    
57A4 CA     2770        DEX            
57A5 10F7   2780        BPL  IN6       
            2790 ;
            2800 ;LOOP TO MOVE BOARD TO GRAPHICS AREA.
            2810 ;THE CHECKERS PROGRAM LOGIC COULD BE ADDED HERE OR A VBLANK INTERRUPT COULD BE USED.
            2820 ;
            2830 LOOP
57A7 20AD57 2840        JSR  UPCHR     
57AA 4CA757 2850        JMP  LOOP      
            2860 ;


ATARI 800 CHECKERS DISPLAY BY C. SHAW 3/31/80


            2870 ;
            2880 ;
            2890 ;
            2900 ;UPCHR -- SUBROUTINE TO MOVE 32 BYTES OF CHECKER BOARD TO DISPLAY RAM.
            2910 ;
            2920 UPCHR
57AD A21F   2930        LDX  #31       ;SQUARE 31 = UPPER LEFT
57AF A000   2940        LDY  #0        
            2950 UPLP1
57B1 A903   2960        LDA  #4-1      ;4 SQUARES/LINE
57B3 8D2050 2970        STA  T0        
            2980 UPLP2
57B6 BD0050 2990        LDA  BOARD,X   
57B9 992654 3000        STA  BRDSP+2,Y ; FOR ROWS SHIFTED TO RIGHT
57BC BDFC4F 3010        LDA  BOARD-4,X 
57BF 993454 3020        STA  BRDSP+$10,Y ; FOR ROWS SHIFTED TO LEFT
57C2 C8     3030        INY            
57C3 C8     3040        INY            
57C4 C8     3050        INY            
57C5 C8     3060        INY            
57C6 CA     3070        DEX            
57C7 CE2050 3080        DEC  T0        
57CA 10EA   3090        BPL  UPLP2     
            3100 ;
57CC 98     3110        TYA            
57CD 18     3120        CLC            
57CE 6910   3130        ADC  #$10      
57D0 A8     3140        TAY            
57D1 8A     3150        TXA            
57D2 E903   3160        SBC  #4-1      ;CARRY IS CLEAR (SUBTRACT 4)
57D4 AA     3170        TAX            
57D5 B0DA   3180        BCS  UPLP1     
57D7 60     3190        RTS            
            3200 ;
            3210 ;
            3220 ;
            3230 ;
            3240 ;DATA
            3250 ;HORIZONTAL POSITION OF PLAYERS (SQUARES) AND MISSILES (SIDE BORDERS).
            3260 ;M0=RIGHT BORDER, M1=LEFT BORDER
            3270 ;M2 & M3 ARE PLACED WITH M1.
            3280 ;             P0, P1, P2, P3, M0, M1, M2, M2
            3290 ITBL
57D8 3C     3300        .BYTE $3C,$5C,$7C,$9C,$BC,$38,$38,$38
57D9 5C
57DA 7C
57DB 9C
57DC BC
57DD 38
57DE 38
57DF 38
            3310 ;
            3320 ;COLOR TABLE
            3330 ITBL1
57E0 34     3340        .BYTE $34,$34,$34,$34 ;4 PLAYERS (RED SQUARES)
57E1 34
57E2 34
57E3 34
57E4 36     3350        .BYTE $36      ;PF0 RED CHECKERS AND MESSAGES


ATARI 800 CHECKERS DISPLAY BY C. SHAW 3/31/80
 

57E5 88     3360        .BYTE $88      ;PF1 BLUE CHARACTERS
57E6 0E     3370        .BYTE $0E      ;PF2 WHITE CHECKERS AND MESSAGES
57E7 26     3380        .BYTE $26      ;PF3 YELLOW BORDER (CHARS & MISSILES)
57E8 00     3390        .BYTE 0        ;BK: BLACK BACKGROUND
            3400 ;
            3410 ;"COPYRIGHT ATARI 1980" MESSAGE
            3420 ;
0000        3430 OF     =    $00       ;FOR PF0 COLOR (RED)
0080        3440 OF2    =    $80       ;FOR PF2 COLOR (WHITE)
0040        3450 OF3    =    $40       ;FOR PF1 COLOR (BLUE)
            3460 TGTBL
57E9 00     3470 COPY   .BYTE SPI,CI+OF,OI+OF,PI+OF,YI+OF,RI+OF,II+OF,GI+OF,HI+OF,TI+OF
57EA 23
57EB 2F
57EC 30
57ED 39
57EE 32
57EF 29
57F0 27
57F1 28
57F2 34
57F3 A1     3480        .BYTE AI+OF2,TI+OF2,AI+OF2,RI+OF2,II+OF2,N1I+OF3,N9I+OF3,N8I+OF3,N0I+OF3
57F4 B4
57F5 A1
57F6 B2
57F7 A9
57F8 51
57F9 59
57FA 58
57FB 50
0 ERRORS

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