mirror of https://github.com/a2-4am/4cade.git
70 lines
1.5 KiB
Plaintext
70 lines
1.5 KiB
Plaintext
;license:MIT
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;(c) 2022 by 4am
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;
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!cpu 6502
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!to "build/FX.INDEXED/DITHER.DISSOLVE",plain
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*=$6000
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row1 = $fe
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row2 = $ff
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src = $3c
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dst = $26
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!source "src/fx/macros.a"
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lda #$00
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sta row1
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lda #$BF
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sta row2
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@loop lda row1
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jsr HGRCalc
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ldy #$27
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- tya
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and #$03
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tax
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lda (src),y
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eor (dst),y ; merge source and destination bits
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@amask and mask1,x ; isolate the bits to replace, zero the rest
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eor (dst),y ; unmerge source and destination bits, leaves 'to keep' destination bits intact
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sta (dst),y ; write the result
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dey
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bpl -
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lda row2
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jsr HGRCalc
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ldy #$27
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- tya
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and #$03
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tax
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lda (src),y
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eor (dst),y
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@bmask and mask3,x
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eor (dst),y
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sta (dst),y
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dey
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bpl -
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lda #$28
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jsr WaitForKeyWithTimeout
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bmi @exit
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inc row1
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dec row2
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lda row1
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cmp #$60
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beq @loop
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ldx @amask+1
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ldy @bmask+1
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stx @bmask+1
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sty @amask+1
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cmp #$C0
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bne @loop
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@exit rts
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mask1 !byte %10110011
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mask2 !byte %11100110
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mask3 !byte %11001100
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mask4 !byte %10011001
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!byte %10110011
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!byte %11100110
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!source "src/wait.a"
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+HGR_CALC_ROUTINES
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