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kolibrios/programs/develop/open watcom/trunk/clib/cgsupp/i8m386.asm
Sergey Semyonov (Serge) 836c97f0ac Clib string & memory functions
git-svn-id: svn://kolibrios.org@553 a494cfbc-eb01-0410-851d-a64ba20cac60
2007-06-26 00:54:22 +00:00

76 lines
3.1 KiB
NASM

;*****************************************************************************
;*
;* Open Watcom Project
;*
;* Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
;*
;* ========================================================================
;*
;* This file contains Original Code and/or Modifications of Original
;* Code as defined in and that are subject to the Sybase Open Watcom
;* Public License version 1.0 (the 'License'). You may not use this file
;* except in compliance with the License. BY USING THIS FILE YOU AGREE TO
;* ALL TERMS AND CONDITIONS OF THE LICENSE. A copy of the License is
;* provided with the Original Code and Modifications, and is also
;* available at www.sybase.com/developer/opensource.
;*
;* The Original Code and all software distributed under the License are
;* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
;* EXPRESS OR IMPLIED, AND SYBASE AND ALL CONTRIBUTORS HEREBY DISCLAIM
;* ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF
;* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR
;* NON-INFRINGEMENT. Please see the License for the specific language
;* governing rights and limitations under the License.
;*
;* ========================================================================
;*
;* Description: WHEN YOU FIGURE OUT WHAT THIS FILE DOES, PLEASE
;* DESCRIBE IT HERE!
;*
;*****************************************************************************
;========================================================================
;== Name: I8M,U8M ==
;== Operation: integer eight byte multiply ==
;== Inputs: EDX;EAX integer M1 ==
;== ECX;EBX integer M2 ==
;== Outputs: EDX;EAX product ==
;== Volatile: ECX, EBX destroyed ==
;========================================================================
include mdef.inc
include struct.inc
modstart i8m
xdefp __I8M
xdefp __U8M
defpe __I8M
defpe __U8M
test edx,edx ; first check for easy (hiwords == 0) case
jnz L1
test ecx,ecx
jnz L1
mul ebx
ret
L1: push eax ; save M1.l
push edx ; save M1.h
mul ecx ; calc M1.l * M2.h -> eax
mov ecx,eax ; save M1.l * M2.h in ecx
pop eax ; get M1.h in eax
mul ebx ; calc M1.h * M2.l -> eax
add ecx,eax ; add above to previous total
pop eax ; get M1.l in eax
mul ebx ; calc M1.l * M2.l -> edx:eax
add edx,ecx ; add previous hiword contribs to hiword
ret ; and return!!!
endproc __U8M
endproc __I8M
endmod
end