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.file "reg_u_mul.S"
/* $OpenBSD: reg_u_mul.s,v 1.1 1996/08/27 10:33:02 downsj Exp $ */
/*
* reg_u_mul.S
*
* Core multiplication routine
*
*
* Copyright (C) 1992,1993,1994
* W. Metzenthen, 22 Parker St, Ormond, Vic 3163,
* Australia. E-mail billm@vaxc.cc.monash.edu.au
* All rights reserved.
*
* This copyright notice covers the redistribution and use of the
* FPU emulator developed by W. Metzenthen. It covers only its use
* in the 386BSD, FreeBSD and NetBSD operating systems. Any other
* use is not permitted under this copyright.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must include information specifying
* that source code for the emulator is freely available and include
* either:
* a) an offer to provide the source code for a nominal distribution
* fee, or
* b) list at least two alternative methods whereby the source
* can be obtained, e.g. a publically accessible bulletin board
* and an anonymous ftp site from which the software can be
* downloaded.
* 3. All advertising materials specifically mentioning features or use of
* this emulator must acknowledge that it was developed by W. Metzenthen.
* 4. The name of W. Metzenthen may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* W. METZENTHEN BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*
* The purpose of this copyright, based upon the Berkeley copyright, is to
* ensure that the covered software remains freely available to everyone.
*
* The software (with necessary differences) is also available, but under
* the terms of the GNU copyleft, for the Linux operating system and for
* the djgpp ms-dos extender.
*
* W. Metzenthen June 1994.
*
*
* $FreeBSD: reg_u_mul.s,v 1.3 1994/06/10 07:44:58 rich Exp $
*
*/
/*---------------------------------------------------------------------------+
| Basic multiplication routine. |
| Does not check the resulting exponent for overflow/underflow |
| |
| reg_u_mul(FPU_REG *a, FPU_REG *b, FPU_REG *c, unsigned int cw); |
| |
| Internal working is at approx 128 bits. |
| Result is rounded to nearest 53 or 64 bits, using "nearest or even". |
+---------------------------------------------------------------------------*/
#include <machine/asm.h>
#include <gnu/arch/i386/fpemul/exception.h>
#include <gnu/arch/i386/fpemul/fpu_asm.h>
#include <gnu/arch/i386/fpemul/control_w.h>
.data
.align 2,0
accum_0:
.long 0
accum_1:
.long 0
.text
.align 2,144
.globl _reg_u_mul
_reg_u_mul:
pushl %ebp
movl %esp,%ebp
pushl %esi
pushl %edi
pushl %ebx
movl PARAM1,%esi
movl PARAM2,%edi
#ifdef PARANOID
testl $0x80000000,SIGH(%esi)
jz L_bugged
testl $0x80000000,SIGH(%edi)
jz L_bugged
#endif PARANOID
#ifdef DENORM_OPERAND
movl EXP(%esi),%eax
cmpl EXP_UNDER,%eax
jg xOp1_not_denorm
call _denormal_operand
orl %eax,%eax
jnz FPU_Arith_exit
xOp1_not_denorm:
movl EXP(%edi),%eax
cmpl EXP_UNDER,%eax
jg xOp2_not_denorm
call _denormal_operand
orl %eax,%eax
jnz FPU_Arith_exit
xOp2_not_denorm:
#endif DENORM_OPERAND
xorl %ecx,%ecx
xorl %ebx,%ebx
movl SIGL(%esi),%eax
mull SIGL(%edi)
movl %eax,accum_0
movl %edx,accum_1
movl SIGL(%esi),%eax
mull SIGH(%edi)
addl %eax,accum_1
adcl %edx,%ebx
/* adcl $0,%ecx *//* overflow here is not possible */
movl SIGH(%esi),%eax
mull SIGL(%edi)
addl %eax,accum_1
adcl %edx,%ebx
adcl $0,%ecx
movl SIGH(%esi),%eax
mull SIGH(%edi)
addl %eax,%ebx
adcl %edx,%ecx
movl EXP(%esi),%eax /* Compute the exponent */
addl EXP(%edi),%eax
subl EXP_BIAS-1,%eax
/* Have now finished with the sources */
movl PARAM3,%edi /* Point to the destination */
movl %eax,EXP(%edi)
/* Now make sure that the result is normalized */
testl $0x80000000,%ecx
jnz LResult_Normalised
/* Normalize by shifting left one bit */
shll $1,accum_0
rcll $1,accum_1
rcll $1,%ebx
rcll $1,%ecx
decl EXP(%edi)
LResult_Normalised:
movl accum_0,%eax
movl accum_1,%edx
orl %eax,%eax
jz L_extent_zero
orl $1,%edx
L_extent_zero:
movl %ecx,%eax
jmp FPU_round
#ifdef PARANOID
L_bugged:
pushl EX_INTERNAL|0x205
call EXCEPTION
pop %ebx
jmp L_exit
L_exit:
popl %ebx
popl %edi
popl %esi
leave
ret
#endif PARANOID
|
