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* use 8086/8088-compatible instructions in the asm version of PutPixelX

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git-svn-id: trunk@41033 -
This commit is contained in:
nickysn 2019-01-24 15:18:30 +00:00
parent bf711c4586
commit 55f8c0f99a
1 changed files with 6 additions and 3 deletions
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9
packages/graph/src/msdos/graph.pp
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@ -2631,15 +2631,18 @@ const CrtAddress: word = 0;
push di
mov di,[Y] ; (* DI = Y coordinate *)
(* Multiply by 80 start *)
mov cl, 4
shl di, cl
mov bx, di
shl di, 6 ; (* Faster on 286/386/486 machines *)
shl bx, 4
shl di, 1
shl di, 1
add di, bx ; (* Multiply Value by 80 *)
(* End multiply by 80 *)
mov cx, [X]
mov ax, cx
{DI = Y * LINESIZE, BX = X, coordinates admissible}
shr ax, 2
shr ax, 1
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 *)