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29 byte X
ov = $0D ; == $FF, initial value for the overflow counter
* = $0304 - (end - scroll)
scroll: jsr $AAD7
loop: lda #$A0
sta $D3E0 - $80, x
sta $0400+40*24+39-$80+1, y ; incrementing rower, y finishes with value $80
sta $0400+40*24-$7B-1, x ; decrementing rower, x finishes with value $7b
adc ov
sta ov
dex
iny
bmi *
bcc loop
jmp scroll
end:
@xenit

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commented Aug 18, 2019

Doesn't jmp take three bytes? bcs would take two.

@xenit

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commented Aug 18, 2019

Ach, got an explanation from nurpax.

@Polyterative

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commented Aug 19, 2019

wild

@badvision

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commented Aug 21, 2019

Christ... I wrote a cycle accurate 65C02 processor emulator and I can't understand how you pulled this off! Bravo!

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