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|
; $Id: __I4M.asm $
;; @file
; Compiler support routines.
;
;
; Copyright (C) 2012-2022 Oracle and/or its affiliates.
;
; This file is part of VirtualBox base platform packages, as
; available from https://www.virtualbox.org.
;
; This program is free software; you can redistribute it and/or
; modify it under the terms of the GNU General Public License
; as published by the Free Software Foundation, in version 3 of the
; License.
;
; This program is distributed in the hope that it will be useful, but
; WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
; General Public License for more details.
;
; You should have received a copy of the GNU General Public License
; along with this program; if not, see <https://www.gnu.org/licenses>.
;
; SPDX-License-Identifier: GPL-3.0-only
;
;*******************************************************************************
;* Exported Symbols *
;*******************************************************************************
public __I4M
if VBOX_BIOS_CPU lt 80386
extrn NeedToImplementOn8086__I4M:near
endif
; MASM (ML.EXE) is used for PXE and no longer understands the .8086 directive.
; WASM is used for the BIOS and understands it just fine.
ifdef __WASM__
.8086
endif
_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
ifdef __WASM__
.8086
endif
else
call NeedToImplementOn8086__I4M
endif
popf
ret
_TEXT ends
end
|
