freebsd-dev/lib/libc/amd64/string/bcopy.S
2005-04-08 05:10:18 +00:00

89 lines
2.5 KiB
ArmAsm

/*-
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from locore.s.
*
* 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 reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 THE REGENTS OR CONTRIBUTORS 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.
*/
#include <machine/asm.h>
__FBSDID("$FreeBSD$");
#if 0
RCSID("$NetBSD: bcopy.S,v 1.2 2003/08/07 16:42:36 agc Exp $")
#endif
/*
* (ov)bcopy (src,dst,cnt)
* ws@tools.de (Wolfgang Solfrank, TooLs GmbH) +49-228-985800
*/
#ifdef MEMCOPY
ENTRY(memcpy)
#else
#ifdef MEMMOVE
ENTRY(memmove)
#else
ENTRY(bcopy)
#endif
#endif
#if defined(MEMCOPY) || defined(MEMMOVE)
movq %rdi,%rax /* return dst */
#else
xchgq %rdi,%rsi
#endif
movq %rdx,%rcx
movq %rdi,%r8
subq %rsi,%r8
cmpq %rcx,%r8 /* overlapping? */
jb 1f
cld /* nope, copy forwards. */
shrq $3,%rcx /* copy by words */
rep
movsq
movq %rdx,%rcx
andq $7,%rcx /* any bytes left? */
rep
movsb
ret
1:
addq %rcx,%rdi /* copy backwards. */
addq %rcx,%rsi
std
andq $7,%rcx /* any fractional bytes? */
decq %rdi
decq %rsi
rep
movsb
movq %rdx,%rcx /* copy remainder by words */
shrq $3,%rcx
subq $7,%rsi
subq $7,%rdi
rep
movsq
cld
ret