94 lines
1.3 KiB
ArmAsm
94 lines
1.3 KiB
ArmAsm
.segment "HEADER"
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.byte $4E, $45, $53, $1A ;Nes header identifier
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.byte 2 ;2x 16KB PRG code
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.byte 1 ; 1x 8KB CHR Data
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.byte $01, $00 ; mapper 0, vertical mirroring
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.segment "VECTORS"
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.addr nmi ; nmi interrupt
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.addr reset ; reset interrupt
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.addr 0 ; external interrupt
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.segment "STARTUP"
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.segment "CHARS"
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.incbin "./CHR-ROM.bin"
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.segment "CODE"
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bg_pallets:
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.byte 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
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check:
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cmp #5
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bcc skip
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clc
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adc #3
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skip:
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rts
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reset:
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ldx #0
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lda #$3F
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sta $2006
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lda #$00
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sta $2006
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loop:
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lda bg_pallets, x
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sta $2007
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inx
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cpx #16
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bne loop
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lda #173
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sta $00
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lda #0
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sta $01
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sta $02
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dabble:
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; check first digit
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lda $01
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and #$F
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jsr check
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sta $03
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lda #$F0
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and $01
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ora $03
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sta $01
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; check second digit
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lda $01
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and #$F0
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lsr
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lsr
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lsr
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lsr
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jsr check
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asl
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asl
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asl
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asl
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sta $03
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lda #$F
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and $01
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ora $03
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sta $01
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; check third digit
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lda $02
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and #$F
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jsr check
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sta $03
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lda #$F0
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and $02
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ora $03
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sta $02
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; Shift
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clc
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rol $00
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rol $01
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rol $02
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lda $00
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cmp #0
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bne dabble
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rts
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nmi:
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rti |