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.file "reg_div.S"
/* $OpenBSD: reg_div.s,v 1.1 1996/08/27 10:32:58 downsj Exp $ */
/*
* reg_div.S
*
* Divide one FPU_REG by another and put the result in a destination FPU_REG.
*
* Call from C as:
* void reg_div(FPU_REG *a, FPU_REG *b, FPU_REG *dest,
*
*
* 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_div.s,v 1.3 1994/06/10 07:44:50 rich Exp $
*
*/
#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>
.text
.align 2
.globl _reg_div
_reg_div:
pushl %ebp
movl %esp,%ebp
pushl %esi
pushl %edi
pushl %ebx
movl PARAM1,%esi
movl PARAM2,%ebx
movl PARAM3,%edi
movb TAG(%esi),%al
orb TAG(%ebx),%al
jne L_div_special /* Not (both numbers TW_Valid) */
#ifdef DENORM_OPERAND
/* Check for denormals */
cmpl EXP_UNDER,EXP(%esi)
jg xL_arg1_not_denormal
call _denormal_operand
orl %eax,%eax
jnz FPU_Arith_exit
xL_arg1_not_denormal:
cmpl EXP_UNDER,EXP(%ebx)
jg xL_arg2_not_denormal
call _denormal_operand
orl %eax,%eax
jnz FPU_Arith_exit
xL_arg2_not_denormal:
#endif DENORM_OPERAND
/* Both arguments are TW_Valid */
movb TW_Valid,TAG(%edi)
movb SIGN(%esi),%cl
cmpb %cl,SIGN(%ebx)
setne (%edi) /* Set the sign, requires SIGN_NEG=1, SIGN_POS=0 */
movl EXP(%esi),%edx
movl EXP(%ebx),%eax
subl %eax,%edx
addl EXP_BIAS,%edx
movl %edx,EXP(%edi)
jmp _divide_kernel
/*-----------------------------------------------------------------------*/
L_div_special:
cmpb TW_NaN,TAG(%esi) /* A NaN with anything to give NaN */
je L_arg1_NaN
cmpb TW_NaN,TAG(%ebx) /* A NaN with anything to give NaN */
jne L_no_NaN_arg
/* Operations on NaNs */
L_arg1_NaN:
L_arg2_NaN:
pushl %edi /* Destination */
pushl %ebx
pushl %esi
call _real_2op_NaN
jmp LDiv_exit
/* Invalid operations */
L_zero_zero:
L_inf_inf:
pushl %edi /* Destination */
call _arith_invalid /* 0/0 or Infinity/Infinity */
jmp LDiv_exit
L_no_NaN_arg:
cmpb TW_Infinity,TAG(%esi)
jne L_arg1_not_inf
cmpb TW_Infinity,TAG(%ebx)
je L_inf_inf /* invalid operation */
cmpb TW_Valid,TAG(%ebx)
je L_inf_valid
#ifdef PARANOID
/* arg2 must be zero or valid */
cmpb TW_Zero,TAG(%ebx)
ja L_unknown_tags
#endif PARANOID
/* Note that p16-9 says that infinity/0 returns infinity */
jmp L_copy_arg1 /* Answer is Inf */
L_inf_valid:
#ifdef DENORM_OPERAND
cmpl EXP_UNDER,EXP(%ebx)
jg L_copy_arg1 /* Answer is Inf */
call _denormal_operand
orl %eax,%eax
jnz FPU_Arith_exit
#endif DENORM_OPERAND
jmp L_copy_arg1 /* Answer is Inf */
L_arg1_not_inf:
cmpb TW_Zero,TAG(%ebx) /* Priority to div-by-zero error */
jne L_arg2_not_zero
cmpb TW_Zero,TAG(%esi)
je L_zero_zero /* invalid operation */
#ifdef PARANOID
/* arg1 must be valid */
cmpb TW_Valid,TAG(%esi)
ja L_unknown_tags
#endif PARANOID
/* Division by zero error */
pushl %edi /* destination */
movb SIGN(%esi),%al
xorb SIGN(%ebx),%al
pushl %eax /* lower 8 bits have the sign */
call _divide_by_zero
jmp LDiv_exit
L_arg2_not_zero:
cmpb TW_Infinity,TAG(%ebx)
jne L_arg2_not_inf
#ifdef DENORM_OPERAND
cmpb TW_Valid,TAG(%esi)
jne L_return_zero
cmpl EXP_UNDER,EXP(%esi)
jg L_return_zero /* Answer is zero */
call _denormal_operand
orl %eax,%eax
jnz FPU_Arith_exit
#endif DENORM_OPERAND
jmp L_return_zero /* Answer is zero */
L_arg2_not_inf:
#ifdef PARANOID
cmpb TW_Zero,TAG(%esi)
jne L_unknown_tags
#endif PARANOID
/* arg1 is zero, arg2 is not Infinity or a NaN */
#ifdef DENORM_OPERAND
cmpl EXP_UNDER,EXP(%ebx)
jg L_copy_arg1 /* Answer is zero */
call _denormal_operand
orl %eax,%eax
jnz FPU_Arith_exit
#endif DENORM_OPERAND
L_copy_arg1:
movb TAG(%esi),%ax
movb %ax,TAG(%edi)
movl EXP(%esi),%eax
movl %eax,EXP(%edi)
movl SIGL(%esi),%eax
movl %eax,SIGL(%edi)
movl SIGH(%esi),%eax
movl %eax,SIGH(%edi)
movb SIGN(%esi),%cl
cmpb %cl,SIGN(%ebx)
jne LDiv_negative_result
movb SIGN_POS,SIGN(%edi)
jmp LDiv_exit
LDiv_set_result_sign:
movb SIGN(%esi),%cl
cmpb %cl,SIGN(%edi)
jne LDiv_negative_result
movb SIGN_POS,SIGN(%ebx)
jmp LDiv_exit
LDiv_negative_result:
movb SIGN_NEG,SIGN(%edi)
LDiv_exit:
leal -12(%ebp),%esp
popl %ebx
popl %edi
popl %esi
leave
ret
L_return_zero:
movb TW_Zero,TAG(%edi)
jmp LDiv_set_result_sign
#ifdef PARANOID
L_unknown_tags:
push EX_INTERNAL | 0x208
call EXCEPTION
/* Generate a NaN for unknown tags */
movl _CONST_QNaN,%eax
movl %eax,(%edi)
movl _CONST_QNaN+4,%eax
movl %eax,SIGL(%edi)
movl _CONST_QNaN+8,%eax
movl %eax,SIGH(%edi)
jmp LDiv_exit
#endif PARANOID
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