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|
.file "reg_u_add.S"
/*
* reg_u_add.S
*
* Add two valid (TW_Valid) FPU_REG numbers, of the same sign, and put the
* result in a destination FPU_REG.
*
* Call from C as:
* void reg_u_add(FPU_REG *arg1, FPU_REG *arg2, FPU_REG *answ,
* int control_w)
*
*
* 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.
*
*
* $FreeBSD$
*
*/
/*
| Kernel addition routine reg_u_add(reg *arg1, reg *arg2, reg *answ).
| Takes two valid reg f.p. numbers (TW_Valid), which are
| treated as unsigned numbers,
| and returns their sum as a TW_Valid or TW_S f.p. number.
| The returned number is normalized.
| Basic checks are performed if PARANOID is defined.
*/
#include <gnu/i386/fpemul/exception.h>
#include <gnu/i386/fpemul/fpu_asm.h>
#include <gnu/i386/fpemul/control_w.h>
.text
.align 2,144
.globl _reg_u_add
_reg_u_add:
pushl %ebp
movl %esp,%ebp
/* subl $16,%esp*/
pushl %esi
pushl %edi
pushl %ebx
movl PARAM1,%esi /* source 1 */
movl PARAM2,%edi /* source 2 */
#ifdef DENORM_OPERAND
cmpl EXP_UNDER,EXP(%esi)
jg xOp1_not_denorm
call _denormal_operand
orl %eax,%eax
jnz FPU_Arith_exit
xOp1_not_denorm:
cmpl EXP_UNDER,EXP(%edi)
jg xOp2_not_denorm
call _denormal_operand
orl %eax,%eax
jnz FPU_Arith_exit
xOp2_not_denorm:
#endif DENORM_OPERAND
/* xorl %ecx,%ecx*/
movl EXP(%esi),%ecx
subl EXP(%edi),%ecx /* exp1 - exp2 */
/* jnc L_arg1_larger*/
jge L_arg1_larger
/* num1 is smaller */
movl SIGL(%esi),%ebx
movl SIGH(%esi),%eax
movl %edi,%esi
negw %cx
jmp L_accum_loaded
L_arg1_larger:
/* num1 has larger or equal exponent */
movl SIGL(%edi),%ebx
movl SIGH(%edi),%eax
L_accum_loaded:
movl PARAM3,%edi /* destination */
movb SIGN(%esi),%dl
movb %dl,SIGN(%edi) /* Copy the sign from the first arg */
movl EXP(%esi),%edx
movl %edx,EXP(%edi) /* Copy exponent to destination */
xorl %edx,%edx /* clear the extension */
#ifdef PARANOID
testl $0x80000000,%eax
je L_bugged
testl $0x80000000,SIGH(%esi)
je L_bugged
#endif PARANOID
/* The number to be shifted is in %eax:%ebx:%edx*/
cmpw $32,%cx /* shrd only works for 0..31 bits */
jnc L_more_than_31
/* less than 32 bits */
shrd %cl,%ebx,%edx
shrd %cl,%eax,%ebx
shr %cl,%eax
jmp L_shift_done
L_more_than_31:
cmpw $64,%cx
jnc L_more_than_63
subb $32,%cl
jz L_exactly_32
shrd %cl,%eax,%edx
shr %cl,%eax
orl %ebx,%ebx
jz L_more_31_no_low /* none of the lowest bits is set*/
orl $1,%edx /* record the fact in the extension*/
L_more_31_no_low:
movl %eax,%ebx
xorl %eax,%eax
jmp L_shift_done
L_exactly_32:
movl %ebx,%edx
movl %eax,%ebx
xorl %eax,%eax
jmp L_shift_done
L_more_than_63:
cmpw $65,%cx
jnc L_more_than_64
movl %eax,%edx
orl %ebx,%ebx
jz L_more_63_no_low
orl $1,%edx
jmp L_more_63_no_low
L_more_than_64:
movl $1,%edx /* The shifted nr always at least one '1'*/
L_more_63_no_low:
xorl %ebx,%ebx
xorl %eax,%eax
L_shift_done:
/* Now do the addition */
addl SIGL(%esi),%ebx
adcl SIGH(%esi),%eax
jnc L_round_the_result
/* Overflow, adjust the result */
rcrl $1,%eax
rcrl $1,%ebx
rcrl $1,%edx
jnc L_no_bit_lost
orl $1,%edx
L_no_bit_lost:
incl EXP(%edi)
L_round_the_result:
jmp FPU_round /* Round the result*/
#ifdef PARANOID
/* If we ever get here then we have problems! */
L_bugged:
pushl EX_INTERNAL|0x201
call EXCEPTION
pop %ebx
jmp L_exit
#endif PARANOID
L_exit:
popl %ebx
popl %edi
popl %esi
leave
ret
|
