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* optimizations in DirectPutPixel16 to avoid the mul instruction

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git-svn-id: trunk@41006 -
This commit is contained in:
nickysn 2019-01-22 17:20:38 +00:00
parent a854411e7c
commit 4336c4d793
1 changed files with 12 additions and 11 deletions
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23
packages/graph/src/msdos/graph.pp
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@ -1956,25 +1956,26 @@ End;
{ setup the bit mask register }
mov al, 8
{ load the bitmask register }
mov cl, [X]
mov si, [X]
mov cx, si
and cl, 07h
mov ah, 80h
shr ah, cl
out dx, ax
{ get the x index and divide by 8 for 16-color }
mov ax, [X]
mov cl, 3
shr ax, cl
push ax
shr si, cl
{ determine the address }
mov ax, 80
mov si, [Y]
mul si
pop cx
add ax,cx
mov di,ax
mov bx, [Y]
inc cx { CL=4 }
shl bx, cl
mov di, bx
shl di, 1
shl di, 1
add di, bx
add di, si
add di, [VideoOfs] { add correct page }
{ send the data through the display memory through set/reset }
add di,[VideoOfs] { add correct page }
mov al,es:[di]
mov es:[di],al