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* some optimizations in GetPixel16

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git-svn-id: trunk@40984 -
This commit is contained in:
nickysn 2019-01-22 01:29:02 +00:00
parent 3b2fc5d34b
commit d653193c36
1 changed files with 20 additions and 26 deletions
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46
packages/graph/src/msdos/graph.pp
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@ -1701,44 +1701,38 @@ end;
out dx,ax
inc dx
xchg ax, di
and ax,0007h
mov cl,07
sub cl,al
mov bl,cl
mov cx, di
not cx
and cl,7
{ read plane 3 }
mov al,es:[si] { read display memory }
shr al,cl
and al,01h
mov ah,al { save bit in AH }
mov ah,es:[si] { read display memory }
shr ah,cl
and ah,01h { save bit in AH }
{ read plane 2 }
mov al,2 { Select plane to read }
out dx,al
mov al,es:[si]
shr al,cl
and al,01h
shl ah,1
or ah,al { save bit in AH }
mov bl,es:[si]
shr bl,cl
shr bl,1
rcl ah,1 { save bit in AH }
{ read plane 1 }
mov al,1 { Select plane to read }
dec ax { Select plane to read }
out dx,al
mov al,es:[si]
shr al,cl
and al,01h
shl ah,1
or ah,al { save bit in AH }
mov bl,es:[si]
shr bl,cl
shr bl,1
rcl ah,1 { save bit in AH }
{ read plane 0 }
mov al,0 { Select plane to read }
dec ax { Select plane to read }
out dx,al
mov al,es:[si]
shr al,cl
and al,01h
shl ah,1
or ah,al { save bit in AH }
mov bl,es:[si]
shr bl,cl
shr bl,1
rcl ah,1 { save bit in AH }
mov al,ah { 16-bit pixel in AX }
{ 1 byte shorter than 'xor ah, ah'; will always set ah to 0, because sign(al)=0 }