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; $Id: bs3-wc16-I8RS.asm $
;; @file
; BS3Kit - 16-bit Watcom C/C++, 64-bit signed integer right shift.
;
;
; Copyright (C) 2007-2019 Oracle Corporation
;
; This file is part of VirtualBox Open Source Edition (OSE), as
; available from http://www.virtualbox.org. This file is free software;
; you can redistribute it and/or modify it under the terms of the GNU
; General Public License (GPL) as published by the Free Software
; Foundation, in version 2 as it comes in the "COPYING" file of the
; VirtualBox OSE distribution. VirtualBox OSE is distributed in the
; hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
;
; The contents of this file may alternatively be used under the terms
; of the Common Development and Distribution License Version 1.0
; (CDDL) only, as it comes in the "COPYING.CDDL" file of the
; VirtualBox OSE distribution, in which case the provisions of the
; CDDL are applicable instead of those of the GPL.
;
; You may elect to license modified versions of this file under the
; terms and conditions of either the GPL or the CDDL or both.
;
%include "bs3kit-template-header.mac"
;;
; 64-bit signed integer left shift.
;
; @returns AX:BX:CX:DX (AX is the most significant, DX the least)
; @param AX:BX:CX:DX Value to shift.
; @param SI Shift count.
;
global $_?I8RS
$_?I8RS:
push si
;
; The 16-bit watcom code differs from the 32-bit one in the way it
; handles the shift count. All 16-bit bits are used in the 16-bit
; code, we do the same as the 32-bit one as we don't want to wast
; time in the below loop.
;
; Using 8086 comatible approach here as it's less hazzle to write
; and smaller.
;
and si, 3fh
jz .return
.next_shift:
sar ax, 1
rcr bx, 1
rcr cx, 1
rcr dx, 1
dec si
jnz .next_shift
.return:
pop si
%ifdef ASM_MODEL_FAR_CODE
retf
%else
ret
%endif
|
