;.Q.!.B ; ====================================== ; HARVEY WALLBANGER by Charles Bachand ; ====================================== ; ====================================== ; Copyright (C) 1982 ANALOG Magazine ; ====================================== ; ------------------------ ; Operating System Equates ; ------------------------ HPOSP0 = $D000 ;player 0 horizontal position M0PF = $D000 ;missile 0/playfield collision HPOSP2 = $D002 ;player 2 horizontal position HPOSP3 = $D003 ;player 3 horizontal position HPOSM0 = $D004 ;missile 0 horizontal position P0PF = $D004 ;player 0/playfield collisions P0PL = $D00C ;player 0 to player collisions GRP2 = $D00F ;player 2 graphics register COLBK = $D01A ;background color GRACTL = $D01D ;graphics control register HITCLR = $D01E ;collision 'HIT' clear CONSOL = $D01F ;console switch port AUDF1 = $D200 ;audio frequency 1 AUDC1 = $D201 ;audio volume 1 AUDF2 = $D202 ;audio frequency 2 AUDC2 = $D203 ;audio volume 2 AUDF3 = $D204 ;audio frequency 3 AUDC3 = $D205 ;audio volume 3 AUDF4 = $D206 ;audio frequency 4 AUDC4 = $D207 ;audio volume 4 RANDOM = $D20A ;random number generator IRQEN = $D20E ;IRQ interrupt enable PMBASE = $D407 ;P/M base address WSYNC = $D40A ;wait for horizontal sync VCOUNT = $D40B ;scan line counter SETVBV = $E45C ;set vertical blank vector XITVBV = $E462 ;vertical blank exit vector SIOINT = $E465 ;serial I/O initialization ATRACT = $004D ;atract mode counter ; ----------------------- ; System Shadow Registers ; ----------------------- RTCLOK = $0012 ;system clock CDTMV1 = $0218 ;system timer 1 CDTMV2 = $021A ;system timer 2 CDTMA1 = $0226 ;system timer 1 vector CDTMA2 = $0228 ;system timer 2 vector SDMCTL = $022F ;DMA control SDLSTL = $0230 ;display list pointer GPRIOR = $026F ;graphics priority STICK0 = $0278 ;joystick 1 STRIG0 = $0284 ;trigger 1 PCOLR0 = $02C0 ;player 0 color PCOLR1 = $02C1 ;player 1 color PCOLR2 = $02C2 ;player 2 color PCOLR3 = $02C3 ;player 3 color COLOR2 = $02C6 ;playfield 2 color COLOR3 = $02C7 ;playfield 3 color COLOR4 = $02C8 ;background color ; ------------------- ; Page Zero Variables ; ------------------- Org $0080 ;area not used by system PIC DS 2 ;rabbit image pointer ; -------------------------- ; Player / Missile RAM Space ; -------------------------- Org $3000 ;out of everyones way PM Org *+$180 ;first area not used MISL Org *+$80 ;Missile graphics area PLR0 Org *+$80 ;player 0 graphics area PLR1 Org *+$80 ;player 1 graphics area PLR2 Org *+$80 ;player 2 graphics area PLR3 Org *+$80 ;player 3 graphics area ; ------------------- ; Program entry point ; ------------------- JMP HARVEY ; ----------------- ; Game display list ; ----------------- DL DB $70,$70 ;32 blank scan lines DB $70,$70 DB $47 ;mode 2 line w/LMS bit DW DISP ;address of game display DB $07,$07 ;9 more mode 2 lines DB $07,$07 DB $07,$07 DB $07,$07 DB $07 DB $70,$70 ;skip 16 lines DB $46 ;mode 1 lime w/LMS bit DW SLINE ;address of score line DB $41 ;jump on vertical blank DW DL ;to start of display list ; --------------- ; Score line data ; --------------- SLINE DB 'R' ; +$A0 DB 'A' ; +$A0 DB 'B' ; +$A0 DB 'B' ; +$A0 DB 'I' ; +$A0 DB 'T' ; +$A0 DB 'S' ; +$A0 DB ':' ; +$A0 RNUM DB '3' ; +$A0 ;number of rabbits DB ' ' ; +$A0 DB 'S' ; +$A0 DB 'C' ; +$A0 DB 'O' ; +$A0 DB 'R' ; +$A0 DB 'E' ; +$A0 DB ':' ; +$A0 SNUM DB '0' ; +$A0 ;score display DB '0' ; +$A0 DB '0' ; +$A0 DB '0' ; +$A0 ; ----------------- ; Game over message ; ----------------- GOMSG DB 'game' DB 0,0,'ov' DB 'er',$80 PSMSG DB 'pres' DB 's',0,0,'s' DB 'tart',$80 ; ------------------- ; Initialization Code ; ------------------- HARVEY CLD ;clear decimal flag JSR SIOINT ;stop cassette LDA #'3' ; +$A0;display for '3' STA RNUM ;3 lives (display) LDA #3 ;get 3 lives STA LIVES ;initialize counter LDA #'0' ; +$A0;display for '0' STA SNUM ;store in the four STA SNUM+1 ;bytes used for the STA SNUM+2 ;score display STA SNUM+3 ;area. MORE LDA #60 ;get 1 second count STA TIM2ST ;set reset value STA CDTMV2 ;set system timer #2 JSR CLSCRN ;clear game playfield LDY #2 ;display 3 numbers (0-2) INUMS JSR PUTNUM ;put the number on screen DEY ;decrement number counter BPL INUMS ;done yet? No. LDA
DL ;high byte DL address STA SDLSTL+1 ;DL pointer (high) LDA #$04 ;set PF over PLAYER STA GPRIOR ;graphics priority LDA #40 ;high wall STA BYLOC ;starting location LDA #196 ;low wall STA BYLOC+1 ;starting location LDA #60 ;left wall STA BXLOC ;starting location STA HPOSP2 ;hardware register LDA #184 ;right wall STA BXLOC+1 ;starting location STA HPOSP3 ;hardware register LDA #122 ;center screen-4 color clocks STA HARX ;Harvey's initial X position LDA #55 ;center P/M-8 bytes STA HARY ;Harvey's initial Y position LDA #$2E ;set P/M DMA on bits STA SDMCTL ;store in DMA control LDA #3 ;set P/M enable bits on STA GRACTL ;store in graphics control LDA >PM ;get high byte of P/M addr STA PMBASE ;point hardware to it LDA #$96 ;light blue color STA COLOR2 ;default color too dark LDA #$48 ;pink color STA COLOR3 ;same here LDA #$18 ;gold color STA PCOLR0 ;set rabbit color LDA #$98 ;blue color STA PCOLR1 ;set missile 1 color LDA #$34 ;red-orange color STA PCOLR2 ;left wall color LDA #$C4 ;green color STA PCOLR3 ;right wall color LDA #1 ;initialize trigger flag- STA STRIGF ;to no shot fired LDX >VB ;address of VB (MSB) LDY T1 ;addr of timer 1 routine MSB STA CDTMA1+1 ;set timer 1 vector MSB LDA T2 ;addr of timer 2 routine MSB STA CDTMA2+1 ;set timer 2 vector MSB LDA #1 ;get 4.25 second count STA CDTMV1+1 ;set system timer #1 LDA #0 ;get a zero STA HITCLR ;reset collision registers STA DIESW ;rabbit is alive STA TICTOC ;reset tictoc counter STA VOL1 ;start with no tictoc sound STA VOL2 ;start with no shuffle noise STA IRQEN ;disable all IRQ interrupts LDX #3 ;set index value to 3 WINCZ STA WINC,X ;zero wall mover counter STA SHOTX,X ;zero X missile location STA SHOTY,X ;zero Y missile location STA SINCX,X ;zero X missile increment STA SINCY,X ;zero Y missile increment DEX ;next wall mover counter BPL WINCZ ;more walls/missiles? Yes. TAX ;set index to zero IM01 STA MISL,X ;clear Missile area STA PLR0,X ;clear Player 0, 1 area INX ;do next byte BNE IM01 ;done yet? No. LDA #$FF ;turn on pixels IM23 STA PLR2,X ;set Player 2, 3 area INX ;do next byte BNE IM23 ;done yet? No. ; ------------------------------------------ ; Main program used to generate the display. ; Actual game done entirely during display's ; vertical blank processing routine. ; ------------------------------------------ HBARS INX ;increment wall pointer TXA ;transfer pointer to Acc AND #1 ;mask off lowest bit TAX ;put back in X register LDA BYLOC,X ;get wall vertical position LSR A ;divide by 2, odd=carry set PHP ;save carry flag VCHECK CMP VCOUNT ;compare with line counter BNE VCHECK ;not yet! STA WSYNC ;start at new line PLP ;get carry flag back BCC ONELIN ;branch on even line number STA WSYNC ;wait for next line ONELIN LDA RANDOM ;random background color AND #$F6 ;max lum of 6 STA COLBK ;for horizontal walls LDY #10 ;let's have 10 lines of this LINES LDA #0 ;get a zero for overlap STA GRP2,X ;background overlaps player STA WSYNC ;wait for next line LDA RANDOM ;random background color AND #$F6 ;max lum of 6 STA COLBK ;for horizontal walls DEY ;decrement line counter BNE LINES ;10 lines done yet? No! LDA COLOR4 ;get original background STA COLBK ;store in background LDA LIVES ;more lives BEQ HB1 ;No. skip code LDA DIESW ;a new life? BPL HB1 ;No. JMP MORE ;Yes. more lives HB1 LDA CONSOL ;check for start switch AND #$01 ;mask off bit BNE HBARS ;start? No. JMP HARVEY ;restart game ; ----------------------------------------- ; System timer #1 interrupt handler. ; Used to speed up walls every 4.25 seconds. ; ----------------------------------------- T1 LDA TIM2ST ;get wall speed CMP #2 ;must stop at two BEQ TIM1 ;is it two? Yes. DEC TIM2ST ;No, then decrement TIM1 LDA #1 ;get 4.25 second cycle time STA CDTMV1+1 ;reset timer #1 RTS ;return ; ------------------------------------------- ; System timer #2 interrupt handler. ; Used to move walls and initiate wall noise. ; ------------------------------------------- T2 LDA TIM2ST ;get timer #2 value STA CDTMV2 ;reset timer #2 INC BYLOC ;move top wall down DEC BYLOC+1 ;move bottom wall up INC BXLOC ;change left wall location LDA BXLOC ;get new location STA HPOSP2 ;change player 2 position DEC BXLOC+1 ;change right wall location LDA BXLOC+1 ;get new location STA HPOSP3 ;change player 3 position INC TICTOC ;increment TIC-TOC counter LDA TICTOC ;get counter value AND #1 ;just need 0 or 1 value TAX ;use for index LDA METRO,X ;get sound frequency STA AUDF1 ;change frequency LDA #$08 ;get volume value STA VOL1 ;save in volume counter RTS ;return ; ------------------------------------------- ; Deferred vertical blank processing routine. ; Here is where all the actual game playing ; takes place. This could be quite long. ; ------------------------------------------- VB LDA DIESW ;rabbit dying? BNE VB0 ;He sure is. LDA LIVES ;any lives left? BNE VB0 ;There sure are. JSR CLSCRN ;clear screen of numbers LDX #0 ;initialize X with zero STX AUDC1 ;stop tictoc sound STX AUDC2 ;stop dying sound STX AUDC3 ;stop gun noise STX AUDC4 ;stop number sound STX CDTMV1 ;shut off the two timers STX CDTMV1+1 ;ditto. STX CDTMV2 ;same here. GOPRT LDA GOMSG,X ;get a character BMI PSINIT ;end of scring? Yes. STA DISP+85,X ;put on screen INX ;increment index JMP GOPRT ;continue PSINIT LDX #0 ;zero the index PSPRT LDA PSMSG,X ;get another character BMI VBXIT ;end of string? Yes. STA DISP+144,X ;put on screen INX ;increment index JMP PSPRT ;continue VBXIT JMP VBX ;exit vertical blank VB0 LDA P0PL ;player/player collisions STA P0PLT ;store in temp variable LDA P0PF ;player to PF collisions STA P0PFT ;store in temp variable LDA NSOUND ;treasure sound counter BMI NOSND ;end of sound? Yes. DEC NSOUND ;decrement volume LSR A ;divide volume by 2 ORA #$A0 ;add pure tone STA AUDC4 ;change volume NOSND LDA VOL1 ;get tictoc volume value BMI SND2 ;if <0 we produce no sound DEC VOL1 ;decrement volume value ORA #$C0 ;mask on the distortion STA AUDC1 ;generate the tictoc sound SND2 LDA VOL2 ;get shuffle volume BMI SND3 ;if <0 we produce no sound DEC VOL2 ;decrement volume value ORA #$80 ;mask on the distortion STA AUDC2 ;generate the shuffle noise SND3 LDA FREQ3 ;get shot frequency INC FREQ3 ;increment shot frequency INC FREQ3 ;do it again INC FREQ3 ;and one last time STA AUDF3 ;change frequency (lower) LDA DIESW ;is rabbit dying BEQ TMOV1 ;No. continue INC DIESW ;Yes. 2 second die period INC PCOLR0 ;change rabbit colors INC PCOLR0 ;again LDA PCOLR0 ;get number ASL A ;*2 ASL A ;*4 ASL A ;*8 STA AUDF2 ;use as frequency LDA #$88 ;get distortion STA AUDC2 ;make sound JMP VBX ;exit vertical blank TMOV1 LDA WINC ;check push wall up BEQ TMOV2 ;push up? No. DEC WINC ;decrement push up counter LDA BYLOC ;get top wall location CMP #28 ;compare with top of screen BEQ TMOV2 ;at top? Yes. DEC BYLOC ;move wall up TMOV2 LDA WINC+1 ;check push wall down BEQ TMOV3 ;push down? No. DEC WINC+1 ;decrement push down counter LDA BYLOC+1 ;get bottom wall location CMP #204 ;compare bottom of screen BEQ TMOV3 ;at bottom? Yes. INC BYLOC+1 ;move wall down TMOV3 LDA WINC+2 ;check push wall left BEQ TMOV4 ;push left? No. DEC WINC+2 ;decrement push left counter LDA BXLOC ;get left wall position STA HPOSP2 ;move left wall player CMP #39 ;check for left wall limit BEQ TMOV4 ;at limit? Yes. DEC BXLOC ;move wall left TMOV4 LDA WINC+3 ;check push wall right BEQ TMOVX ;push right? No. DEC WINC+3 ;decrement push right counter LDA BXLOC+1 ;get right wall position STA HPOSP3 ;move right wall player CMP #208 ;check for right wall limit BEQ TMOVX ;at limit? Yes. INC BXLOC+1 ;move wall right TMOVX LDA #0 ;get a zero STA ATRACT ;poke out atract mode STA XTEMP ;zero rabbit X increment STA YTEMP ;zero rabbit Y increment LDA STICK0 ;get joystick value CMP #$0F ;at center position? BEQ CENTER ;Yes. skip code LDA RTCLOK+2 ;get real time clock LSB AND #$07 ;at 1/7.5 second mark? BNE CENTER ;No. skip code LDA #$10 ;get shuffle frequency STA AUDF2 ;set frequency register LDA #$04 ;get volume value STA VOL2 ;set shuffle volume CENTER LDA STICK0 ;get joystick value SEC ;set carry for subtract SBC #5 ;values 5-15 only ASL A ;5-15 now 0,2,4,... TAX ;use for index LDA RTCLOK+2 ;get real time clock LSB ROR A ;divide by 2 ROR A ;divide by 4 ROR A ;divide by 8 ROR A ;carry set/reset at .13 sec LDA PK1,X ;get rabbit picture LSB BCC PICMVL ;other pic at .13 sec? No. LDA PK2,X ;get alternate picture LSB PICMVL STA PIC ;store LSB of pic address LDA PK1+1,X ;get rabbit picture MSB BCC PICMVH ;other pic at .13 sec? No. LDA PK2+1,X ;get alternate picture MSB PICMVH STA PIC+1 ;store MSB of pic address LDX #3 ;count 3 downto 0 CHKSTK LSR STICK0 ;shift bit into carry BCS CHKNXT ;correct direction? No. LDA STBLX,X ;check X movement direction BEQ CHK0 ;movement allowed? No. STA XTEMP ;store X movement value CHK0 LDA STBLY,X ;check Y movement direction BEQ CHKNXT ;movement allowed? No. STA YTEMP ;store Y movement value CHKNXT DEX ;do next stick position BPL CHKSTK ;done yet? No. LDA P0PLT ;get player 0 collision CMP #$0C ;left/right squeze? BNE NOSQUE ;No. Check indvdual walls DEC RNUM ;decrement lives display DEC LIVES ;decrement lines counter INC DIESW ;the rabbit has died switch NOSQUE AND #$04 ;check left wall collision BEQ BMPRT ;hit left wall? No. INC HARX ;Yes. Move rabbit to right LDA #0 ;get zero value STA XTEMP ;stop rabbit X movement BMPRT LDA P0PLT ;get player 0 collision AND #$08 ;check right wall collision BEQ BMPUP ;hit right wall? No. DEC HARX ;Yes. Move rabbit to left LDA #0 ;get zero value STA XTEMP ;stop rabbit X movement BMPUP CLC ;clear carry for add LDA BYLOC ;top wall Y location ADC #4 ;offset by 4 LSR A ;divide by 2 CMP HARY ;compare rabbit Y location BCC BMPDN ;hit top wall? No. DEC RNUM ;decrement lives display DEC LIVES ;decrement lines counter INC DIESW ;the rabbit has died switch BMPDN LDA HARY ;get rabbit Y location ADC #10 ;offset by 10 ASL A ;multiply by 2 CMP BYLOC+1 ;compare bottom wall Y BCC NOBMP ;hit bottom wall? No. DEC RNUM ;decrement lives display DEC LIVES ;decrement lines counter INC DIESW ;the rabbit has died switch NOBMP CLC ;clear carry for add LDA HARX ;get rabbit X position ADC XTEMP ;add X increment STA HARX ;save new rabbit X position STA HPOSP0 ;position rabbit player 0 CLC ;clear carry for add LDA HARY ;get rabbit Y position ADC YTEMP ;add Y increment STA HARY ;save new rabbit Y position TAX ;use position as index LDY #0 ;initialize picture counter MOVHAR LDA (PIC),Y ;get rabbit picture byte STA PLR0,X ;store in player 0 area INX ;increment player pointer INY ;increment picture pointer CPY #14 ;check for end of picture BNE MOVHAR ;at end? No. LDA STRIG0 ;get trigger value CMP STRIGF ;compare with trigger flag STA STRIGF ;save new trigger flag BCS NOFIRE ;shot fired? No. LDA XTEMP ;rabbit X increment ORA YTEMP ;OR rabbit Y increment BNE FIREGN ;rabbit stationary? No. INC STRIGF ;set trigger flag to 1 BNE NOFIRE ;skip fire routine FIREGN LDA #$40 ;initialize frequency STA FREQ3 ;zero audio freq 3 LDA #$04 ;shot volume + distortion STA AUDC3 ;enable volume 3 INC SHOTS ;increment shot pointer LDA SHOTS ;get shot pointer AND #3 ;make it 0-3 only TAX ;use pointer for index LDA XTEMP ;get rabbit X increment ASL A ;make shot twice as fast STA SINCX,X ;set missile X increment LDA YTEMP ;get rabbit Y increment ASL A ;make shot twice as fast STA SINCY,X ;set missile Y increment CLC ;clear carry for add LDA HARX ;get rabbit X position ADC #3 ;move to center X of rabbit STA SHOTX,X ;shot initial X position LDA HARY ;get rabbit Y position ADC #8 ;move to center Y of rabbit STA SHOTY,X ;shot initial Y position NOFIRE LDA #0 ;zero accumulator TAX ;zero X index ERASES STA MISL,X ;zero all missiles INX ;next missile byte BPL ERASES ;done? No. LDX #3 ;count 3 downto 0 PLOTS LDA SINCX,X ;get missile X increment ORA SINCY,X ;OR missile Y increment BEQ NOPLOT ;any movement? No. LDA SHOTY,X ;missile Y position CLC ;clear carry for add ADC SINCY,X ;add Y increment STA SHOTY,X ;store new Y position TAY ;Y position now index ASL A ;multiply by 2 ADC #2 ;offset for compare CMP BYLOC+1 ;compare with bottom wall BCC HITTP ;hit bottom wall? No. JSR ZINCXY ;zero missile increments ADC WINC+1 ;add 8 to wall increment STA WINC+1 ;new bottom wall increment JMP PLOTNH ;continue HITTP SBC #12 ;offset for bottom side CMP BYLOC ;compare with top wall BCS PLOTNH ;hit top wall? No. JSR ZINCXY ;zero missile increments ADC WINC ;add 8 to wall increment STA WINC ;new top wall increment PLOTNH LDA MISL,Y ;get missile byte ORA MISMSK,X ;OR missile mask STA MISL,Y ;store new byte LDA MISL+1,Y ;get next missile byte ORA MISMSK,X ;OR missile mask STA MISL+1,Y ;store new next byte LDA M0PF,X ;missile/playfield collision LDY #0 ;init Y register MHPF ROR A ;collision? BCC MHPF0 ;No. No. No. JMP MHIT ;Yes. Yes. Yes. MHPF0 INY ;try next bit CPY #4 ;any more bits? BNE MHPF ;Certainly! Yuk. Yuk. CLC ;clear carry for add LDA SHOTX,X ;get missile X position ADC SINCX,X ;add X increment STA SHOTX,X ;store new X position STA HPOSM0,X ;position missile CMP BXLOC+1 ;compare missile with wall BCC HITLF ;hit right wall? No. JSR ZINCXY ;zero missile increments ADC WINC+3 ;add 8 to wall increment STA WINC+3 ;new wall increment JMP NOPLOT ;continue HITLF SBC #6 ;offset for right side CMP BXLOC ;compare with left wall BCS NOPLOT ;hit left wall? No. JSR ZINCXY ;zero missile increments ADC WINC+2 ;add 8 to wall increment STA WINC+2 ;new wall increment NOPLOT DEX ;next missile BMI NOPL1 ;missiles done? Yes. JMP PLOTS ;continue loop NOPL1 LDX #3 ;set up pointer LDA #0 ;zero accumulator CHKMIS ORA SINCX,X ;OR in X increments ORA SINCY,X ;OR in Y increments DEX ;decrement pointer BPL CHKMIS ;at end? No. CMP #0 ;check shot increments BNE NOSSND ;any increments? Yes. STA AUDC3 ;end shot sound NOSSND LDY #0 ;initialize Y index MISHIT LSR P0PFT ;shift collision to carry BCC MH1 ;collision w/number? No. JSR ERANUM ;erase the number LDA VTBL,Y ;get value of number PHA ;save on stack JSR PUTNUM ;put out a new number PLA ;get old number TAY ;use as counter value BEQ SCX ;was it zero? Yes. SCORER LDX #3 ;point to score low digit SC1 INC SNUM,X ;increment digit LDA SNUM,X ;get digit CMP #'9' ; +$A1 ;past ATASCII '9'+color? BNE SCY ;No. continue LDA #'0' ; +$A0 ;reset digit STA SNUM,X ;change score display DEX ;point to next digit BPL SC1 ;score rolled over? No. SCY DEY ;decrement value BNE SCORER ;scoring done? No. SCX JMP VBX ;exit routine MH1 INY ;check next color digit CPY #3 ;done 0-2 yet? BNE MISHIT ;No. continue VBX STA HITCLR ;clear collision registers JMP XITVBV ;exit deferred vertical blank MHIT TXA ;save X register PHA ;on stack JSR ERANUM ;erase number hit and JSR PUTNUM ;put a new one on screen PLA ;pull X register TAX ;from stack JMP NOPLOT ;continue on ; ------------------------- ; Commonly used subroutines ; ------------------------- ; Clear missile display area ZINCXY LDA #0 ;get zero value STA SINCX,X ;zero missile X increment STA SINCY,X ;zero missile Y increment CLC ;clear carry for add LDA #8 ;get value for add RTS ;we return to the program ; Clear the game playfield CLSCRN LDX #200 ;set 0-199 bytes LDA #0 ;to zero CL0 STA DISP-1,X ;store in display DEX ;count down BNE CL0 ;past zero yet? No. RTS ;return to program ; Put random number from 0-9 on screen at ; a random location 0-199 PUTNUM LDX RANDOM ;get random number CPX #200 ;is number < 200? BCS PUTNUM ;No. try another LDA DISP,X ;see if space is occupied BNE PUTNUM ;Yes. try again PN0 LDA RANDOM ;get another random number AND #$0F ;limit it to 0-15 CMP #10 ;is number < 10? BCS PN0 ;No. try another STA VTBL,Y ;save number ORA CTBL,Y ;OR with color STA DISP,X ;put number on screen TXA ;move screen offset to A STA ATBL,Y ;save screen offset RTS ;end of routine ; Erase number from screen ERANUM LDA #0 ;get zero for blank LDX ATBL,Y ;get # position on screen STA DISP,X ;blank number on screen LDA RANDOM ;get random number AND #$1F ;mask off high bits ORA #$10 ;make it $10-$1F STA AUDF4 ;use as sound frequency LDA #30 ;initialize- STA NSOUND ;volume counter RTS ;end of routine ; ---------------------------- ; Program tables and constants ; ---------------------------- MISMSK DB $03 ;missile 0 mask DB $0C ;missile 1 mask DB $30 ;missile 2 mask DB $C0 ;missile 3 mask HARLF1 DB 0,0 ;left view #1 DB $12,$0A DB $3C,$74 DB $3C,$1C DB $1E,$3E DB $3F,$7E HARLF2 DB 0,0 ;left view #2 DB $0B,$0A DB $3C,$74 DB $3C,$1C DB $1E,$3E DB $3E,$F7 HARRT1 DB 0,0 ;right view #1 DB $48,$50 DB $3C,$2E DB $3C,$38 DB $78,$7C DB $FC,$7E HARRT2 DB 0,0 ;right view #2 DB $D0,$50 DB $3C,$2E DB $3C,$38 DB $78,$7C DB $7C,$EF HARFR1 DB 0,0 ;front view #1 DB $42,$24 DB $3C,$14 DB $3C,$18 DB $3C,$7E DB $7E,$E7 HARFR2 DB 0,0 ;front view #2 DB $42,$24 DB $3C,$28 DB $3C,$18 DB $3C,$7E DB $7E,$E7 HARDN1 DB 0,0 ;down view #1 DB $44,$24 DB $3C,$14 DB $3C,$18 DB $3C,$7E DB $FE,$07 HARDN2 DB 0,0 ;down view #2 DB $22,$24 DB $3C,$28 DB $3C,$18 DB $3C,$7E DB $7F,$E0 HARUP1 DB 0,0 ;up view #1 DB $44,$24 DB $3C,$3C DB $3C,$18 DB $3C,$66 DB $FE,$07 HARUP2 DB 0,0 ;up view #2 DB $22,$24 DB $3C,$3C DB $3C,$18 DB $3C,$66 DB $7F,$E0 DB 0,0 PK1 DW HARRT1 ;rabbit pictures set 1 DW HARRT1 DW HARRT1 DW 0 DW HARLF1 DW HARLF1 DW HARLF1 DW 0 DW HARDN1 DW HARUP1 DW HARFR1 PK2 DW HARRT2 ;rabbit pictures set 2 DW HARRT2 DW HARRT2 DW 0 DW HARLF2 DW HARLF2 DW HARLF2 DW 0 DW HARDN2 DW HARUP2 DW HARFR2 CTBL DB $10,$50 ;color offset table DB $90 METRO DB 38,41 ;tictoc tones STBLX DB $01,$FF ;joystick X increments DB $00,$00 STBLY DB $00,$00 ;joystick Y increments DB $01,$FF ; --------------------- ; Variable Storage Area ; --------------------- HARX DB 0 ;Harvey's X locatin HARY DB 0 ;Harvey's Y location BYLOC DB 0,0 ;horizontal wall Y locations BXLOC DB 0,0 ;vertical wall X locations VOL1 DB 0 ;tictoc volume VOL2 DB 0 ;shuffle volume FREQ3 DB 0 ;shot frequency NSOUND DB 0 ;pick number up sound TICTOC DB 0 ;tictoc sound counter TIM2ST DB 0 ;wall speed timer WINC DB 0,0,0,0 ;wall mover counters STRIGF DB 0 ;trigger compare register XTEMP DB 0 ;temporary variable YTEMP DB 0 ;temporary variable P0PLT DB 0 ;player 0 collision shadow P0PFT DB 0 ;PL to PF collision shadow VTBL DB 0,0,0 ;value of #'s on screen ATBL DB 0,0,0 ;screen offset to #'s SHOTS DB 0 ;shot enable counter LIVES DB 0 ;number of lives left DIESW DB 0 ;rabbit dying switch SHOTX DB 0,0,0,0 ;missile X location SHOTY DB 0,0,0,0 ;missile Y location SINCX DB 0,0,0,0 ;missile X increment SINCY DB 0,0,0,0 ;missile Y increment DISP Org *+200 ;screen display area End HARVEY