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/* Highly optimized version for i586.
Copyright (C) 1997 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <sysdep.h>
#include "asm-syntax.h"
/*
INPUT PARAMETERS:
dst (sp + 4)
src (sp + 8)
len (sp + 12)
*/
.text
ENTRY (memcpy)
pushl %edi
pushl %esi
movl 12(%esp), %edi /* dst */
movl 16(%esp), %esi /* src */
movl 20(%esp), %ecx /* len */
movl %edi, %eax
/* We need this in any case. */
cld
/* Cutoff for the big loop is a size of 32 bytes since otherwise
the loop will never be entered. */
cmpl $32, %ecx
jbe L(1)
negl %eax
andl $3, %eax
subl %eax, %ecx
xchgl %eax, %ecx
rep; movsb
movl %eax, %ecx
subl $32, %ecx
js L(2)
/* Read ahead to make sure we write in the cache since the stupid
i586 designers haven't implemented read-on-write-miss. */
movl (%edi), %eax
L(3): movl 28(%edi), %edx
/* Now correct the loop counter. Please note that in the following
code the flags are not changed anymore. */
subl $32, %ecx
movl (%esi), %eax
movl 4(%esi), %edx
movl %eax, (%edi)
movl %edx, 4(%edi)
movl 8(%esi), %eax
movl 12(%esi), %edx
movl %eax, 8(%edi)
movl %edx, 12(%edi)
movl 16(%esi), %eax
movl 20(%esi), %edx
movl %eax, 16(%edi)
movl %edx, 20(%edi)
movl 24(%esi), %eax
movl 28(%esi), %edx
movl %eax, 24(%edi)
movl %edx, 28(%edi)
leal 32(%esi), %esi
leal 32(%edi), %edi
jns L(3)
/* Correct extra loop counter modification. */
L(2): addl $32, %ecx
#ifndef memcpy
movl 12(%esp), %eax /* dst */
#endif
L(1): rep; movsb
#ifdef memcpy
movl %edi, %eax
#endif
popl %esi
popl %edi
ret
END (memcpy)
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