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/* i80586 sub_n -- Sub two limb vectors of the same length > 0 and store
* sum in a third limb vector.
*
* Copyright (C) 1992, 1994, 1995, 1998,
* 2001, 2002 Free Software Foundation, Inc.
*
* This file is part of Libgcrypt.
*
* Libgcrypt is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* Libgcrypt is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*
* Note: This code is heavily based on the GNU MP Library.
* Actually it's the same code with only minor changes in the
* way the data is stored; this is to support the abstraction
* of an optional secure memory allocation which may be used
* to avoid revealing of sensitive data due to paging etc.
*/
#include "sysdep.h"
#include "asm-syntax.h"
/*******************
* mpi_limb_t
* _gcry_mpih_sub_n( mpi_ptr_t res_ptr, (sp + 4)
* mpi_ptr_t s1_ptr, (sp + 8)
* mpi_ptr_t s2_ptr, (sp + 12)
* mpi_size_t size) (sp + 16)
*/
.text
ALIGN (3)
.globl C_SYMBOL_NAME(_gcry_mpih_sub_n)
C_SYMBOL_NAME(_gcry_mpih_sub_n:)
pushl %edi
pushl %esi
pushl %ebx
pushl %ebp
movl 20(%esp),%edi /* res_ptr */
movl 24(%esp),%esi /* s1_ptr */
movl 28(%esp),%ebp /* s2_ptr */
movl 32(%esp),%ecx /* size */
movl (%ebp),%ebx
decl %ecx
movl %ecx,%edx
shrl $3,%ecx
andl $7,%edx
testl %ecx,%ecx /* zero carry flag */
jz Lend
pushl %edx
ALIGN (3)
Loop: movl 28(%edi),%eax /* fetch destination cache line */
leal 32(%edi),%edi
L1: movl (%esi),%eax
movl 4(%esi),%edx
sbbl %ebx,%eax
movl 4(%ebp),%ebx
sbbl %ebx,%edx
movl 8(%ebp),%ebx
movl %eax,-32(%edi)
movl %edx,-28(%edi)
L2: movl 8(%esi),%eax
movl 12(%esi),%edx
sbbl %ebx,%eax
movl 12(%ebp),%ebx
sbbl %ebx,%edx
movl 16(%ebp),%ebx
movl %eax,-24(%edi)
movl %edx,-20(%edi)
L3: movl 16(%esi),%eax
movl 20(%esi),%edx
sbbl %ebx,%eax
movl 20(%ebp),%ebx
sbbl %ebx,%edx
movl 24(%ebp),%ebx
movl %eax,-16(%edi)
movl %edx,-12(%edi)
L4: movl 24(%esi),%eax
movl 28(%esi),%edx
sbbl %ebx,%eax
movl 28(%ebp),%ebx
sbbl %ebx,%edx
movl 32(%ebp),%ebx
movl %eax,-8(%edi)
movl %edx,-4(%edi)
leal 32(%esi),%esi
leal 32(%ebp),%ebp
decl %ecx
jnz Loop
popl %edx
Lend:
decl %edx /* test %edx w/o clobbering carry */
js Lend2
incl %edx
Loop2:
leal 4(%edi),%edi
movl (%esi),%eax
sbbl %ebx,%eax
movl 4(%ebp),%ebx
movl %eax,-4(%edi)
leal 4(%esi),%esi
leal 4(%ebp),%ebp
decl %edx
jnz Loop2
Lend2:
movl (%esi),%eax
sbbl %ebx,%eax
movl %eax,(%edi)
sbbl %eax,%eax
negl %eax
popl %ebp
popl %ebx
popl %esi
popl %edi
ret
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