Last active
September 11, 2018 08:05
-
-
Save jmcd/53b634dc4a564d5106249c6dc950d8c9 to your computer and use it in GitHub Desktop.
Display like The Matrix movie on a C64 in 6502 assembly
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| *= $c000 ; 49152 | |
| !to "matrix.prg", cbm | |
| !cpu 6502 ; set processor type | |
| JSR main | |
| RTS | |
| _snake_count !byte $05 | |
| _snake_lengths !byte $05, $08, 10, 14, 20 | |
| _snake_xs !byte 03, 10, 20, 30, 34 | |
| _snake_ys !byte 10, 05, 20, 02, 07 | |
| _current_snake !byte $00 | |
| main | |
| JSR setupscreen | |
| JSR randomizeallsnakes | |
| _main_loop | |
| JSR drawallsnakes | |
| JSR moveallsnakes | |
| JMP _main_loop | |
| RTS | |
| moveallsnakes | |
| LDA #$00 | |
| STA _current_snake | |
| _moveallsnakes_loop | |
| LDA _current_snake | |
| CMP _snake_count | |
| BEQ _end_moveallsnakes | |
| LDY _current_snake | |
| LDA _snake_ys, y | |
| CLC | |
| ADC #$01 | |
| STA _snake_ys, y | |
| INC _current_snake | |
| JMP _moveallsnakes_loop | |
| _end_moveallsnakes | |
| RTS | |
| randomizeallsnakes | |
| LDA #$00 | |
| STA _current_snake | |
| _randomizeallsnakes_loop | |
| LDA _current_snake | |
| CMP _snake_count | |
| BEQ _end_randomizeallsnakes | |
| JSR randomizesnake | |
| INC _current_snake | |
| JMP _randomizeallsnakes_loop | |
| _end_randomizeallsnakes | |
| RTS | |
| randomizesnake | |
| LDY _current_snake | |
| JSR GETRAND | |
| LDA RANDOM+1 | |
| ;AND #39 | |
| STA $0400 | |
| STA _snake_xs, y | |
| LDA RANDOM+1 | |
| STA $0403 | |
| AND #24 | |
| STA $0401 | |
| STA _snake_ys, y | |
| RTS | |
| checksnake | |
| LDY _current_snake | |
| LDA #$00 | |
| STA _addscreen_location | |
| LDA #$D8 | |
| STA _addscreen_location+1 | |
| LDA _snake_xs,y | |
| STA _addscreen_x | |
| LDA _snake_ys,y | |
| STA _addscreen_y | |
| JSR addscreen | |
| LDA _addscreen_location | |
| STA _subscreen_location | |
| LDA _addscreen_location+1 | |
| STA _subscreen_location+1 | |
| LDA #$00 | |
| STA _subscreen_x | |
| LDY _current_snake | |
| LDA _snake_lengths,y | |
| CLC | |
| ADC #$01 | |
| STA _subscreen_y | |
| JSR subscreen | |
| LDA _subscreen_location | |
| STA _isvalidscreencolorlocation_location | |
| LDA _subscreen_location+1 | |
| STA _isvalidscreencolorlocation_location+1 | |
| JSR isvalidscreencolorlocation | |
| LDA #$00 | |
| CMP _isvalidscreencolorlocation_result | |
| BEQ _checksnake_end | |
| LDA #$01 | |
| CMP _isvalidscreencolorlocation_result | |
| BEQ _checksnake_end | |
| JSR randomizesnake | |
| LDY _current_snake | |
| LDA #$00 | |
| STA _snake_ys,y | |
| JMP drawsnake | |
| _checksnake_end | |
| RTS | |
| drawallsnakes | |
| LDA #$00 | |
| STA _current_snake | |
| _drawallsnakes_loop | |
| LDA _current_snake | |
| CMP _snake_count | |
| BEQ _end_drawallsnakes | |
| JSR checksnake | |
| JSR drawsnake | |
| INC _current_snake | |
| JMP _drawallsnakes_loop | |
| _end_drawallsnakes | |
| RTS | |
| _temp_location !byte $00, $00 | |
| drawsnake | |
| LDY _current_snake | |
| LDA #$00 | |
| STA _addscreen_location | |
| LDA #$D8 | |
| STA _addscreen_location+1 | |
| LDA _snake_xs,y | |
| STA _addscreen_x | |
| LDA _snake_ys,y | |
| STA _addscreen_y | |
| JSR addscreen | |
| _drawsnake_main | |
| LDA _addscreen_location | |
| STA _pokescreencolorlocation_location | |
| LDA _addscreen_location+1 | |
| STA _pokescreencolorlocation_location+1 | |
| LDA #$01 | |
| STA _pokescreencolorlocation_value | |
| JSR pokescreencolorlocation | |
| LDY _current_snake | |
| LDA _addscreen_location | |
| STA _temp_location | |
| LDA _addscreen_location+1 | |
| STA _temp_location+1 | |
| LDX _snake_lengths, y | |
| _tail | |
| CPX #$00 | |
| BEQ _blacken | |
| LDA _pokescreencolorlocation_location | |
| STA _sub16_param1 | |
| LDA _pokescreencolorlocation_location+1 | |
| STA _sub16_param1+1 | |
| LDA #$28 | |
| STA _sub16_param2 | |
| LDA #$00 | |
| STA _sub16_param2+1 | |
| JSR sub16 | |
| LDA _sub16_result | |
| STA _pokescreencolorlocation_location | |
| LDA _sub16_result+1 | |
| STA _pokescreencolorlocation_location+1 | |
| LDA #$05 | |
| STA _pokescreencolorlocation_value | |
| JSR pokescreencolorlocation | |
| DEX | |
| JMP _tail | |
| _blacken | |
| LDA _pokescreencolorlocation_location | |
| STA _sub16_param1 | |
| LDA _pokescreencolorlocation_location+1 | |
| STA _sub16_param1+1 | |
| LDA #$28 | |
| STA _sub16_param2 | |
| LDA #$00 | |
| STA _sub16_param2+1 | |
| JSR sub16 | |
| LDA _sub16_result | |
| STA _pokescreencolorlocation_location | |
| LDA _sub16_result+1 | |
| STA _pokescreencolorlocation_location+1 | |
| LDA #$00 | |
| STA _pokescreencolorlocation_value | |
| JSR pokescreencolorlocation | |
| RTS | |
| _setupscreen_current_location !byte $00, $04, $00, $D8 ;data | |
| setupscreen | |
| LDX #$00 | |
| STX $0286 | |
| STX $D020 | |
| STX $D021 | |
| LDA _setupscreen_current_location | |
| STA _cmp16_param1 | |
| LDA _setupscreen_current_location+1 | |
| STA _cmp16_param1+1 | |
| LDA #$E8 | |
| STA _cmp16_param2 | |
| LDA #$07 | |
| STA _cmp16_param2+1 | |
| JSR cmp16 | |
| BEQ _end_setupscreen | |
| LDA _setupscreen_current_location | |
| STA _poke_location | |
| LDA _setupscreen_current_location+1 | |
| STA _poke_location+1 | |
| JSR getrandomchar | |
| LDA _getrandomchar_result | |
| STA _poke_value | |
| JSR poke | |
| LDA _setupscreen_current_location+2 | |
| STA _poke_location | |
| LDA _setupscreen_current_location+3 | |
| STA _poke_location+1 | |
| LDA #$00 | |
| STA _poke_value | |
| JSR poke | |
| CLC | |
| LDA _setupscreen_current_location | |
| ADC #$01 | |
| STA _setupscreen_current_location | |
| LDA _setupscreen_current_location+1 | |
| ADC #$00 | |
| STA _setupscreen_current_location+1 | |
| CLC | |
| LDA _setupscreen_current_location+2 | |
| ADC #$01 | |
| STA _setupscreen_current_location+2 | |
| LDA _setupscreen_current_location+3 | |
| ADC #$00 | |
| STA _setupscreen_current_location+3 | |
| JMP setupscreen | |
| _end_setupscreen | |
| RTS | |
| _getrandomchar_result !byte $00 | |
| getrandomchar | |
| JSR GETRAND | |
| LDA RANDOM+1 | |
| STA _getrandomchar_result | |
| RTS | |
| _isvalidscreencolorlocation_location !byte $00, $00 | |
| _isvalidscreencolorlocation_result !byte $00 ; 0 valid, 1 before screen, 2 after | |
| isvalidscreencolorlocation | |
| LDA #$00 | |
| STA _isvalidscreencolorlocation_result | |
| _isvalidscreencolorlocation_checkbefore | |
| LDA _isvalidscreencolorlocation_location | |
| STA _cmp16_param1 | |
| LDA _isvalidscreencolorlocation_location+1 | |
| STA _cmp16_param1+1 | |
| LDA #$00 | |
| STA _cmp16_param2 | |
| LDA #$D8 | |
| STA _cmp16_param2+1 | |
| CLC | |
| JSR cmp16 | |
| BCS _isvalidscreencolorlocation_checkafter | |
| LDA #$01 | |
| STA _isvalidscreencolorlocation_result | |
| RTS | |
| _isvalidscreencolorlocation_checkafter | |
| LDA #$E8 | |
| STA _cmp16_param2 | |
| LDA #$DB | |
| STA _cmp16_param2+1 | |
| CLC | |
| JSR cmp16 | |
| BCC _end_isvalidscreencolorlocation | |
| LDA #$02 | |
| STA _isvalidscreencolorlocation_result | |
| _end_isvalidscreencolorlocation | |
| RTS | |
| _pokescreencolorlocation_location !byte $00, $00 | |
| _pokescreencolorlocation_value !byte $00 | |
| pokescreencolorlocation | |
| LDA _pokescreencolorlocation_location | |
| STA _isvalidscreencolorlocation_location | |
| LDA _pokescreencolorlocation_location+1 | |
| STA _isvalidscreencolorlocation_location+1 | |
| JSR isvalidscreencolorlocation | |
| LDA _isvalidscreencolorlocation_result | |
| CMP #$00 | |
| BNE _end_pokescreencolorlocation | |
| LDA _pokescreencolorlocation_location | |
| STA _poke_location | |
| LDA _pokescreencolorlocation_location+1 | |
| STA _poke_location+1 | |
| LDA _pokescreencolorlocation_value | |
| STA _poke_value | |
| JSR poke | |
| _end_pokescreencolorlocation | |
| RTS | |
| _peek_location !byte $00, $00 | |
| _peek_result !byte $00 | |
| peek | |
| LDA _peek_location | |
| STA _peek_load+1 | |
| LDA _peek_location+1 | |
| STA _peek_load+2 | |
| _peek_load | |
| LDA $0000 | |
| STA _peek_result | |
| RTS | |
| _poke_location !byte $00, $00 | |
| _poke_value !byte $00 | |
| poke | |
| LDA _poke_location | |
| STA _poke_store+1 | |
| LDA _poke_location+1 | |
| STA _poke_store+2 | |
| LDA _poke_value | |
| _poke_store | |
| STA $0000 | |
| RTS | |
| _add16_param1 !byte $00, $00 | |
| _add16_param2 !byte $00, $00 | |
| _add16_result !byte $00, $00 | |
| add16 | |
| CLC | |
| LDA _add16_param1 | |
| ADC _add16_param2 | |
| STA _add16_result | |
| LDA _add16_param1+1 | |
| ADC _add16_param2+1 | |
| STA _add16_result+1 | |
| RTS | |
| _sub16_param1 !byte $00, $00 | |
| _sub16_param2 !byte $00, $00 | |
| _sub16_result !byte $00, $00 | |
| sub16 | |
| SEC | |
| LDA _sub16_param1+0 | |
| SBC _sub16_param2+0 | |
| STA _sub16_result+0 | |
| LDA _sub16_param1+1 | |
| SBC _sub16_param2+1 | |
| STA _sub16_result+1 | |
| RTS | |
| _cmp16_param1 !byte $00, $00 | |
| _cmp16_param2 !byte $00, $00 | |
| cmp16 | |
| LDA _cmp16_param1+1 | |
| CMP _cmp16_param2+1 | |
| BNE _end_cmp16 | |
| LDA _cmp16_param1 | |
| CMP _cmp16_param2 | |
| _end_cmp16 | |
| RTS | |
| _addscreen_location !byte $00, $00 | |
| _addscreen_x !byte $00 | |
| _addscreen_y !byte $00 | |
| addscreen | |
| CLC ; Add x | |
| LDA _addscreen_location | |
| ADC _addscreen_x | |
| STA _addscreen_location | |
| LDA _addscreen_location+1 | |
| ADC #$00 | |
| STA _addscreen_location+1 ; Done add x | |
| LDY _addscreen_y | |
| _addscreen_loop | |
| CPY #$00 | |
| BEQ _end_addscreen | |
| LDA _addscreen_location | |
| STA _add16_param1 | |
| LDA _addscreen_location+1 | |
| STA _add16_param1+1 | |
| LDA #$28 | |
| STA _add16_param2 | |
| LDA #$00 | |
| STA _add16_param2+1 | |
| JSR add16 | |
| LDA _add16_result | |
| STA _addscreen_location | |
| LDA _add16_result+1 | |
| STA _addscreen_location+1 | |
| CLC | |
| DEY | |
| JMP _addscreen_loop | |
| _end_addscreen | |
| RTS | |
| _subscreen_location !byte $00, $00 | |
| _subscreen_x !byte $00 | |
| _subscreen_y !byte $00 | |
| subscreen | |
| SEC ; sub x | |
| LDA _subscreen_location | |
| SBC _subscreen_x | |
| STA _subscreen_location | |
| LDA _subscreen_location+1 | |
| SBC #$00 | |
| STA _subscreen_location+1 ; Done sub x | |
| LDY _subscreen_y | |
| _subscreen_loop | |
| CPY #$00 | |
| BEQ _end_subscreen | |
| LDA _subscreen_location | |
| STA _sub16_param1 | |
| LDA _subscreen_location+1 | |
| STA _sub16_param1+1 | |
| LDA #$28 | |
| STA _sub16_param2 | |
| LDA #$00 | |
| STA _sub16_param2+1 | |
| JSR sub16 | |
| LDA _sub16_result | |
| STA _subscreen_location | |
| LDA _sub16_result+1 | |
| STA _subscreen_location+1 | |
| CLC | |
| DEY | |
| JMP _subscreen_loop | |
| _end_subscreen | |
| RTS | |
| ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
| ; From http://www.ffd2.com/fridge/math/rand1.s | |
| RANDOM !byte 0,0 | |
| TEMP1 !byte 0,0 | |
| GETRAND | |
| LDA RANDOM+1 | |
| STA TEMP1 | |
| LDA RANDOM | |
| ASL | |
| ROL TEMP1 | |
| ASL | |
| ROL TEMP1 | |
| CLC | |
| ADC RANDOM | |
| PHA | |
| LDA TEMP1 | |
| ADC RANDOM+1 | |
| STA RANDOM+1 | |
| PLA | |
| ADC #$11 | |
| STA RANDOM | |
| LDA RANDOM+1 | |
| ADC #$36 | |
| STA RANDOM+1 | |
| RTS | |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment