kolibrios-fun/programs/develop/open watcom/trunk/clib/cgsupp/fdc386.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

86 lines
3.6 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!
;*
;*****************************************************************************
;<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
;<>
;<> __FDC - floating double comparison
;<> input: EDX:EAX - operand 1
;<> ECX:EBX - operand 2
;<> if op1 > op2, 1 is returned in EAX
;<> if op1 < op2, -1 is returned in EAX
;<> if op1 = op2, 0 is returned in EAX
;<>
;<>
;<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
include mdef.inc
include struct.inc
modstart fdc386
xdefp __FDC
defpe __FDC
push EBP ; save BP
test EDX,07ff00000h ; check for zero
_if e ; if it is then
sub EDX,EDX ; - make whole damn thing a zero
_endif ; endif
test ECX,07ff00000h ; check op2 for zero
_if e ; if it is then
sub ECX,ECX ; - make whole damn thing a zero
_endif ; endif
mov EBP,ECX ; save op2 exponent
xor EBP,EDX ; see about signs of the operands
mov EBP,0 ; clear result
js short cmpdone ; quif arg1 & arg2 have diff signs
_guess ; guess
cmp EDX,ECX ; - compare high words of arg1, arg2
_quif ne ; - quif not equal
cmp EAX,EBX ; - compare 2nd words of arg1, arg2
_endguess ; endguess
_if ne ; if arg1 <> arg2
rcr ECX,1 ; - save carry in CX
xor EDX,ECX ; - sign of BX is sign of result
cmpdone: _shl EDX,1 ; - get sign of result into carry
sbb EBP,0 ; - BP gets sign of result
_shl EBP,1 ; - double BP
inc EBP ; - make BP -1 or 1
_endif ; endif
mov EAX,EBP ; get result
pop EBP ; restore BP
ret ; return to caller
endproc __FDC
endmod
end