bcopy.S revision 144730 
1/*-
2 * Copyright (c) 1990 The Regents of the University of California.
3 * All rights reserved.
4 *
5 * This code is derived from locore.s.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <machine/asm.h>
33__FBSDID("$FreeBSD: head/lib/libc/amd64/string/bcopy.S 144730 2005-04-07 03:56:03Z alc $");
34
35#if 0
36	RCSID("$NetBSD: bcopy.S,v 1.2 2003/08/07 16:42:36 agc Exp $")
37#endif
38
39	/*
40	 * (ov)bcopy (src,dst,cnt)
41	 *  ws@tools.de     (Wolfgang Solfrank, TooLs GmbH) +49-228-985800
42	 */
43
44#ifdef MEMCOPY
45ENTRY(memcpy)
46#else
47#ifdef MEMMOVE
48ENTRY(memmove)
49#else
50ENTRY(bcopy)
51#endif
52#endif
53#if defined(MEMCOPY) || defined(MEMMOVE)
54	movq	%rdi,%r11	/* save dest */
55#else
56	xchgq	%rdi,%rsi
57#endif
58	movq	%rdx,%rcx
59	movq	%rdi,%rax
60	subq	%rsi,%rax
61	cmpq	%rcx,%rax	/* overlapping? */
62	jb	1f
63	cld			/* nope, copy forwards. */
64	shrq	$3,%rcx		/* copy by words */
65	rep
66	movsq
67	movq	%rdx,%rcx
68	andq	$7,%rcx		/* any bytes left? */
69	rep
70	movsb
71#if defined(MEMCOPY) || defined(MEMMOVE)
72	movq	%r11,%rax
73#endif
74	ret
751:
76	addq	%rcx,%rdi	/* copy backwards. */
77	addq	%rcx,%rsi
78	std
79	andq	$7,%rcx		/* any fractional bytes? */
80	decq	%rdi
81	decq	%rsi
82	rep
83	movsb
84	movq	%rdx,%rcx	/* copy remainder by words */
85	shrq	$3,%rcx
86	subq	$7,%rsi
87	subq	$7,%rdi
88	rep
89	movsq
90#if defined(MEMCOPY) || defined(MEMMOVE)
91	movq	%r11,%rax
92#endif
93	cld
94	ret
95