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[BZ #4314] 

* sysdeps/i386/i686/memcpy.S: Optimize copying of aligned buffers.
This commit is contained in:
Ulrich Drepper 2008-04-09 20:01:52 +00:00
parent 3f98186568
commit 2120860435
2 changed files with 49 additions and 11 deletions
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3
ChangeLog
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@ -1,5 +1,8 @@
2008-04-09 Ulrich Drepper <drepper@redhat.com>
[BZ #4314]
* sysdeps/i386/i686/memcpy.S: Optimize copying of aligned buffers.
[BZ #5209]
* sysdeps/unix/sysv/syscalls.list: The times syscall doesn't return
an error value.

57
sysdeps/i386/i686/memcpy.S
View File

@ -1,7 +1,7 @@
/* Copy memory block and return pointer to beginning of destination block
For Intel 80x86, x>=6.
This file is part of the GNU C Library.
Copyright (C) 1999, 2000, 2003, 2004 Free Software Foundation, Inc.
Copyright (C) 1999, 2000, 2003, 2004, 2008 Free Software Foundation, Inc.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1999.
The GNU C Library is free software; you can redistribute it and/or
@ -41,15 +41,56 @@ END (__memcpy_chk)
ENTRY (BP_SYM (memcpy))
ENTER
movl LEN(%esp), %ecx
movl %edi, %eax
movl DEST(%esp), %edi
movl %esi, %edx
movl SRC(%esp), %esi
CHECK_BOUNDS_BOTH_WIDE (%edi, DEST(%esp), %ecx)
CHECK_BOUNDS_BOTH_WIDE (%esi, SRC(%esp), %ecx)
movl %edi, %ecx
xorl %esi, %ecx
andl $3, %ecx
movl LEN(%esp), %ecx
cld
jne .Lunaligned
cmpl $3, %ecx
jbe .Lunaligned
testl $3, %esi
je 1f
movsb
decl %ecx
testl $3, %esi
je 1f
movsb
decl %ecx
testl $3, %esi
je 1f
movsb
decl %ecx
1: pushl %eax
movl %ecx, %eax
shrl $2, %ecx
rep
movsl
movl %eax, %ecx
andl $3, %ecx
rep
movsb
popl %eax
.Lend: movl %eax, %edi
movl %edx, %esi
movl DEST(%esp), %eax
RETURN_BOUNDED_POINTER (DEST(%esp))
LEAVE
RET_PTR
/* When we come here the pointers do not have the same
alignment or the length is too short. No need to optimize for
aligned memory accesses. */
.Lunaligned:
shrl $1, %ecx
jnc 1f
movsb
@ -58,12 +99,6 @@ ENTRY (BP_SYM (memcpy))
movsw
2: rep
movsl
movl %eax, %edi
movl %edx, %esi
movl DEST(%esp), %eax
RETURN_BOUNDED_POINTER (DEST(%esp))
LEAVE
RET_PTR
jmp .Lend
END (BP_SYM (memcpy))
libc_hidden_builtin_def (memcpy)