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Copy pathcart.s
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cart.s
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.segment "HEADER"
.byte "NES" ; identification string
.byte $1a
.byte $02 ; amount of PRG ROM in 16k units
.byte $01 ; amount of CHR ROM in 8k units
.byte $00 ; mapper and mirroring
.byte $00, $00, $00, $00
.byte $00, $00, $00, $00, $00
.segment "ZEROPAGE"
VAR: .RES 1 ; reserves 1 byte of memory
.segment "STARTUP"
RESET:
sei ; disable interrupts
cld ; turn off decimal mode
ldx #%10000000 ; disable sound IRQ
stx $4017
ldx #$00
stx $4010 ; disable PCM
; initialize stack register
ldx #$ff
txs ; transfer x to the stack
; clear PPU registers
ldx #$00
stx $2000
stx $2001
; wait for vblank
:
bit $2002
bpl :-
; clearing up 2k memory
txa
CLEARMEMORY:
sta $0000, x
sta $0100, x
sta $0300, x
sta $0400, x
sta $0500, x
sta $0600, x
sta $0700, x
lda #$ff
sta $0200, x
lda #$00
inx
cpx #$00
bne CLEARMEMORY
; wait for vblank
:
bit $2002
bpl :-
; setting sprite range
lda #$02
sta $4014
nop
; setting palette data
lda #$3f
sta $2006
lda #$00
sta $2006
ldx #$00
LOADPALETTES:
lda PALETTEDATA, x
sta $2007
inx
cpx #$20
bne LOADPALETTES
ldx #$00
LOADSPRITES:
lda SPRITEDATA, x
sta $0200, x
inx
cpx #$20
bne LOADSPRITES
LOADBACKGROUND:
lda $2002 ; read PPU status to reset high/low latch
lda #$21
sta $2006
lda #$00
sta $2006
ldx #$00
LOADBACKGROUNDP1:
lda BACKGROUNDDATA, x
sta $2007
inx
cpx #$00
bne LOADBACKGROUNDP1
LOADBACKGROUNDP2:
lda BACKGROUNDDATA+256, x
sta $2007
inx
cpx #$00
bne LOADBACKGROUNDP2
;LOAD BACKGROUND PALETTEDATA
lda #$23 ;$23D0
sta $2006
lda #$D0
sta $2006
ldx #$00
LOADBACKGROUNDPALETTEDATA:
lda BACKGROUNDPALETTEDATA, X
sta $2007
inx
cpx #$20
bne LOADBACKGROUNDPALETTEDATA
;RESET SCROLL
lda #$00
sta $2005
sta $2005
; Enable interrupts
cli
lda #%10010000
sta $2000 ; when vblank occurs, call nmi
lda #%00011110 ; show sprites and background
sta $2001
INFLOOP:
jmp INFLOOP
NMI:
lda #$02 ; load sprite range
sta $4014
rti
PALETTEDATA:
.byte $00, $0F, $00, $10, $00, $0A, $15, $01, $00, $29, $28, $27, $00, $34, $24, $14 ;background palettes
.byte $31, $0F, $15, $30, $00, $0F, $11, $30, $00, $0F, $30, $27, $00, $3C, $2C, $1C ;sprite palettes
SPRITEDATA:
;Y, SPRITE NUM, attributes, X
;76543210
;||||||||
;||||||++- Palette (4 to 7) of sprite
;|||+++--- Unimplemented
;||+------ Priority (0: in front of background; 1: behind background)
;|+------- Flip sprite horizontally
;+-------- Flip sprite vertically
.byte $40, $00, $00, $40
.byte $40, $01, $00, $48
.byte $48, $10, $00, $40
.byte $48, $11, $00, $48
;sword
.byte $50, $08, %00000001, $80
.byte $50, $08, %01000001, $88
.byte $58, $18, %00000001, $80
.byte $58, $18, %01000001, $88
BACKGROUNDDATA: ;512 BYTES
.byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$01,$02,$03,$04,$05,$00,$00,$00,$00,$00,$00,$00,$06,$07,$00,$00,$00,$00,$00,$00,$00,$00,$00
.byte $00,$00,$00,$00,$00,$00,$00,$08,$09,$0a,$0b,$0b,$0b,$0c,$0d,$0e,$0f,$10,$11,$56,$13,$14,$0b,$15,$00,$00,$00,$00,$00,$00,$00,$00
.byte $00,$00,$00,$00,$00,$00,$00,$16,$17,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$18,$19,$00,$00,$00,$00,$00,$00,$00
.byte $00,$00,$00,$00,$00,$1a,$1b,$1c,$1d,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$1e,$06,$1f,$00,$00,$00,$00,$00
.byte $00,$00,$20,$21,$22,$23,$18,$24,$25,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$26,$27,$28,$00,$29,$2a,$00,$00,$00,$00,$00
.byte $00,$00,$2b,$2c,$2d,$0b,$11,$2e,$2f,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$30,$31,$32,$33,$34,$35,$00,$00,$00,$00,$00
.byte $00,$00,$00,$00,$36,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$18,$37,$38,$39,$3a,$00,$00,$00,$00,$00,$00
.byte $00,$00,$00,$00,$3b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$0b,$3c,$3d,$3e,$00,$00,$00,$00,$00,$00,$00,$00
.byte $00,$00,$00,$00,$3f,$40,$0b,$0b,$0b,$41,$42,$43,$44,$0b,$0b,$45,$0b,$0b,$0b,$0b,$46,$47,$48,$00,$00,$00,$00,$00,$00,$00,$00,$00
.byte $00,$00,$00,$00,$00,$49,$0b,$0b,$4a,$4b,$00,$4c,$4d,$0b,$4e,$4f,$50,$0b,$0b,$51,$00,$52,$53,$00,$00,$00,$00,$00,$00,$00,$00,$00
.byte $00,$00,$00,$00,$00,$3f,$54,$55,$12,$00,$00,$00,$57,$58,$59,$00,$5a,$5b,$5c,$5d,$00,$5e,$5f,$00,$00,$00,$00,$00,$00,$00,$00,$00
.byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$60,$61,$00,$00,$62,$63,$64,$65,$00,$66,$67,$68,$00,$00,$00,$00,$00,$00,$00,$00
.byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$69,$00,$00,$6a,$6b,$6c,$00,$6d,$6e,$6f,$70,$00,$00,$00,$00,$00,$00,$00,$00
.byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$71,$72,$73,$0b,$74,$75,$76,$77,$78,$00,$00,$00,$00,$00,$00
.byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$79,$7a,$7b,$7c,$7d,$7e,$7f,$80,$81,$82,$00,$00,$00,$00,$00
.byte $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$4c,$83,$84,$85,$86,$35,$87,$00,$00,$00,$00,$00,$00
BACKGROUNDPALETTEDATA: ;32 bytes
.byte $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55
.byte $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55, $55
.segment "VECTORS"
.word NMI ; nonmaskable interrupt
.word RESET ; reset event handler
; specialized hardware interrupts
.segment "CHARS"
.incbin "cart-rom.chr"