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Updated BG scroll latch behaviour

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pagefault
2005-03-28 19:03:44 +00:00
parent bac0d276dc
commit d76cbf9af1
1 changed files with 53 additions and 28 deletions
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81
zsnes/src/cpu/regsw.inc
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@@ -650,17 +650,22 @@ reg210Cw:
; BG1 horizontal scroll register ; BG1 horizontal scroll register
reg210Dw: reg210Dw:
mov bl,byte[bg1scrolx+1] xor ebx,ebx
mov byte[bg1scrolx],bl mov byte[bg1scrolx],al
mov byte[bg1scrolx+1],al shl word[bg1scrolx],8
mov bl,[bgscroltemp]
add word[bg1scrolx],bx
mov byte[bgscroltemp],al
ret ret
; BG1 vertical scroll register ; BG1 vertical scroll register
reg210Ew: reg210Ew:
mov bl,byte[bg1scroly+1] xor ebx,ebx
add bl,[bgscroltemp] mov byte[bg1scroly],al
mov byte[bg1scroly],bl shl word[bg1scroly],8
mov byte[bg1scroly+1],al mov bl,[bgscroltemp]
add word[bg1scroly],bx
mov byte[bgscroltemp],al
ret ret
SECTION .bss SECTION .bss
@@ -669,47 +674,67 @@ SECTION .text
; BG2 horizontal scroll register ; BG2 horizontal scroll register
reg210Fw: reg210Fw:
mov bl,byte[bg2scrolx+1] xor ebx,ebx
mov byte[bg2scrolx],bl mov byte[bg2scrolx],al
mov byte[bg2scrolx+1],al shl word[bg2scrolx],8
mov bl,[bgscroltemp]
add word[bg2scrolx],bx
mov byte[bgscroltemp],al
ret ret
; BG2 vertical scroll register ; BG2 vertical scroll register
reg2110w: reg2110w:
mov bl,byte[bg2scroly+1] xor ebx,ebx
add bl,[bgscroltemp] mov byte[bg2scroly],al
mov byte[bg2scroly],bl shl word[bg2scroly],8
mov byte[bg2scroly+1],al mov bl,[bgscroltemp]
add word[bg2scroly],bx
mov byte[bgscroltemp],al
ret ret
; BG3 horizontal scroll register ; BG3 horizontal scroll register
reg2111w: reg2111w:
mov bl,byte[bg3scrolx+1] xor ebx,ebx
mov byte[bg3scrolx],bl mov byte[bg3scrolx],al
mov byte[bg3scrolx+1],al shl word[bg3scrolx],8
mov bl,[bgscroltemp]
add word[bg3scrolx],bx
mov byte[bgscroltemp],al
ret ret
section .data
NEWSYM latchbg3, db 0
section .text
; BG3 vertical scroll register ; BG3 vertical scroll register
reg2112w: reg2112w:
mov bl,byte[bg3scroly+1] xor ebx,ebx
add bl,[bgscroltemp] mov byte[bg3scroly],al
mov byte[bg3scroly],bl shl word[bg3scroly],8
mov byte[bg3scroly+1],al mov bl,[bgscroltemp]
add word[bg3scroly],bx
mov byte[bgscroltemp],al
ret ret
; BG4 horizontal scroll register ; BG4 horizontal scroll register
reg2113w: reg2113w:
mov bl,byte[bg4scrolx+1] xor ebx,ebx
mov byte[bg4scrolx],bl mov byte[bg4scrolx],al
mov byte[bg4scrolx+1],al shl word[bg4scrolx],8
mov bl,[bgscroltemp]
add word[bg4scrolx],bx
mov byte[bgscroltemp],al
ret ret
; BG4 vertical scroll register ; BG4 vertical scroll register
reg2114w: reg2114w:
mov bl,byte[bg4scroly+1] xor ebx,ebx
add bl,[bgscroltemp] mov byte[bg4scroly],al
mov byte[bg4scroly],bl shl word[bg4scroly],8
mov byte[bg4scroly+1],al mov bl,[bgscroltemp]
add word[bg4scroly],bx
mov byte[bgscroltemp],al
ret ret
; Video port control ; Video port control