xref: /netbsd-src/common/lib/libc/arch/x86_64/string/bcopy.S (revision 8b0f9554ff8762542c4defc4f70e1eb76fb508fa)
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
34#if defined(LIBC_SCCS)
35	RCSID("$NetBSD: bcopy.S,v 1.2 2007/11/12 18:41:59 ad Exp $")
36#endif
37
38	/*
39	 * (ov)bcopy (src,dst,cnt)
40	 *  ws@tools.de     (Wolfgang Solfrank, TooLs GmbH) +49-228-985800
41	 */
42
43#ifdef MEMCOPY
44ENTRY(memcpy)
45#else
46#ifdef MEMMOVE
47ENTRY(memmove)
48#else
49ENTRY(bcopy)
50#endif
51#endif
52#if defined(MEMCOPY) || defined(MEMMOVE)
53	movq	%rdi,%r11	/* save dest */
54#else
55	xchgq	%rdi,%rsi
56#endif
57	movq	%rdx,%rcx
58	movq	%rdi,%rax
59	subq	%rsi,%rax
60	cmpq	%rcx,%rax	/* overlapping? */
61	jb	1f
62	/* nope, copy forwards. */
63	shrq	$3,%rcx		/* copy by words */
64	rep
65	movsq
66	movq	%rdx,%rcx
67	andq	$7,%rcx		/* any bytes left? */
68	rep
69	movsb
70#if defined(MEMCOPY) || defined(MEMMOVE)
71	movq	%r11,%rax
72#endif
73	ret
741:
75	addq	%rcx,%rdi	/* copy backwards. */
76	addq	%rcx,%rsi
77	std
78	andq	$7,%rcx		/* any fractional bytes? */
79	decq	%rdi
80	decq	%rsi
81	rep
82	movsb
83	movq	%rdx,%rcx	/* copy remainder by words */
84	shrq	$3,%rcx
85	subq	$7,%rsi
86	subq	$7,%rdi
87	rep
88	movsq
89#if defined(MEMCOPY) || defined(MEMMOVE)
90	movq	%r11,%rax
91#endif
92	cld
93	ret
94