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|
; $Id: __I4M.asm $
;; @file
; Compiler support routines.
;
;
; Copyright (C) 2012-2019 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.
;
;*******************************************************************************
;* Exported Symbols *
;*******************************************************************************
public __I4M
if VBOX_BIOS_CPU lt 80386
extrn NeedToImplementOn8086__I4M:near
endif
.8086
_TEXT segment public 'CODE' use16
assume cs:_TEXT
;;
; 32-bit signed multiplication.
;
; @param dx:ax Factor 1.
; @param cx:bx Factor 2.
; @returns dx:ax Result.
; cx, es may be modified; di is preserved
;
__I4M:
pushf
if VBOX_BIOS_CPU ge 80386
.386
push eax
push edx
push ecx
push ebx
rol eax, 16
mov ax, dx
ror eax, 16
xor edx, edx
shr ecx, 16
mov cx, bx
imul ecx ; eax * ecx -> edx:eax
pop ebx
pop ecx
pop edx
ror eax, 16
mov dx, ax
add sp, 2
pop ax
rol eax, 16
.8086
else
call NeedToImplementOn8086__I4M
endif
popf
ret
_TEXT ends
end
|
