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* asm version of GetPixelX converted to pure asm

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git-svn-id: trunk@41019 -
This commit is contained in:
nickysn 2019-01-23 15:23:48 +00:00
parent 46f3c742f3
commit c86da93af8
1 changed files with 33 additions and 36 deletions
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69
packages/graph/src/msdos/graph.pp
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@ -2487,45 +2487,42 @@ const CrtAddress: word = 0;
GetPixelX := Mem[SegA000:offset];
end;
{$else asmgraph}
function GetPixelX(X,Y: smallint): ColorType;
begin
asm
function GetPixelX(X,Y: smallint): ColorType; assembler;
asm
{$ifdef FPC_MM_HUGE}
mov ax, SEG SegA000
mov es, ax
mov es, es:[SegA000]
mov ax, SEG SegA000
mov es, ax
mov es, es:[SegA000]
{$else FPC_MM_HUGE}
mov es, [SegA000]
mov es, [SegA000]
{$endif FPC_MM_HUGE}
mov di,[Y] ; (* DI = Y coordinate *)
add di,[StartYViewPort]
(* Multiply by 80 start *)
mov cl, 4
shl di, cl
mov bx, di
shl di, 1
shl di, 1
add di, bx ; (* Multiply Value by 80 *)
(* End multiply by 80 *)
mov cx, [X]
add cx, [StartXViewPort]
mov ax, cx
{DI = Y * LINESIZE, BX = X, coordinates admissible}
shr ax, 1 ; (* Faster on 286/86 machines *)
shr ax, 1
add di, ax ; {DI = Y * LINESIZE + (X SHR 2) }
add di, [VideoOfs] ; (* Pointing at start of Active page *)
(* Select plane to use *)
mov dx, 03c4h
mov ax, FirstPlane ; (* Map Mask & Plane Select Register *)
and cl, 03h ; (* Get Plane Bits *)
shl ah, cl ; (* Get Plane Select Value *)
out dx, ax
(* End selection of plane *)
mov al, ES:[DI]
xor ah, ah
mov @Result, ax
end;
mov di,[Y] ; (* DI = Y coordinate *)
add di,[StartYViewPort]
(* Multiply by 80 start *)
mov cl, 4
shl di, cl
mov bx, di
shl di, 1
shl di, 1
add di, bx ; (* Multiply Value by 80 *)
(* End multiply by 80 *)
mov cx, [X]
add cx, [StartXViewPort]
mov ax, cx
{DI = Y * LINESIZE, BX = X, coordinates admissible}
shr ax, 1 ; (* Faster on 286/86 machines *)
shr ax, 1
add di, ax ; {DI = Y * LINESIZE + (X SHR 2) }
add di, [VideoOfs] ; (* Pointing at start of Active page *)
(* Select plane to use *)
mov dx, 03c4h
mov ax, FirstPlane ; (* Map Mask & Plane Select Register *)
and cl, 03h ; (* Get Plane Bits *)
shl ah, cl ; (* Get Plane Select Value *)
out dx, ax
(* End selection of plane *)
mov al, ES:[DI]
xor ah, ah
end;
{$endif asmgraph}