xref: /openbsd-src/sys/lib/libkern/arch/amd64/bcopy.S (revision a28daedfc357b214be5c701aa8ba8adb29a7f1c2)
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. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgement:
17 *	This product includes software developed by the University of
18 *	California, Berkeley and its contributors.
19 * 4. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#include <machine/asm.h>
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
49#ifdef OVBCOPY
50ENTRY(ovbcopy)
51#else
52ENTRY(bcopy)
53#endif
54#endif
55#endif
56#if defined(MEMCOPY) || defined(MEMMOVE)
57	movq	%rdi,%r11	/* save dest */
58#else
59	xchgq	%rdi,%rsi
60#endif
61	movq	%rdx,%rcx
62	movq	%rdi,%rax
63	subq	%rsi,%rax
64	cmpq	%rcx,%rax	/* overlapping? */
65	jb	1f
66	cld			/* nope, copy forwards. */
67	shrq	$3,%rcx		/* copy by words */
68	rep
69	movsq
70	movq	%rdx,%rcx
71	andq	$7,%rcx		/* any bytes left? */
72	rep
73	movsb
74#if defined(MEMCOPY) || defined(MEMMOVE)
75	movq	%r11,%rax
76#endif
77	ret
781:
79	addq	%rcx,%rdi	/* copy backwards. */
80	addq	%rcx,%rsi
81	std
82	andq	$7,%rcx		/* any fractional bytes? */
83	decq	%rdi
84	decq	%rsi
85	rep
86	movsb
87	movq	%rdx,%rcx	/* copy remainder by words */
88	shrq	$3,%rcx
89	subq	$7,%rsi
90	subq	$7,%rdi
91	rep
92	movsq
93#if defined(MEMCOPY) || defined(MEMMOVE)
94	movq	%r11,%rax
95#endif
96	cld
97	ret
98