1/*-
2 * Copyright (c) 1990, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Chris Torek.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by the University of
19 *	California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#if defined(LIBC_SCCS) && !defined(lint)
38static char sccsid[] = "@(#)bcopy.c	8.1 (Berkeley) 6/4/93";
39#endif /* LIBC_SCCS and not lint */
40
41#ifdef HAVE_CONFIG_H
42# include <config.h>
43#endif
44
45#ifndef HAVE_MEMMOVE
46#ifdef HAVE_SYS_TYPES_H
47#include <sys/types.h>
48#endif
49#include <string.h>
50
51#include "l_stdlib.h"
52
53/*
54 * sizeof(word) MUST BE A POWER OF TWO
55 * SO THAT wmask BELOW IS ALL ONES
56 */
57typedef	int word;		/* "word" used for optimal copy speed */
58
59#define	wsize	sizeof(word)
60#define	wmask	(wsize - 1)
61
62/*
63 * Copy a block of memory, handling overlap.
64 * This is the routine that actually implements
65 * (the portable versions of) bcopy, memcpy, and memmove.
66 */
67void *
68memmove(
69	void *dst0,
70	const void *src0,
71	register size_t length
72	)
73{
74	register char *dst = dst0;
75	register const char *src = src0;
76	register size_t t;
77
78	if (length == 0 || dst == src)		/* nothing to do */
79	    goto done;
80
81	/*
82	 * Macros: loop-t-times; and loop-t-times, t>0
83	 */
84#define	TLOOP(s) if (t) TLOOP1(s)
85#define	TLOOP1(s) do { s; } while (--t)
86
87	if ((unsigned long)dst < (unsigned long)src) {
88		/*
89		 * Copy forward.
90		 */
91		t = (int)src;	/* only need low bits */
92		if ((t | (int)dst) & wmask) {
93			/*
94			 * Try to align operands.  This cannot be done
95			 * unless the low bits match.
96			 */
97			if ((t ^ (int)dst) & wmask || length < wsize)
98			    t = length;
99			else
100			    t = wsize - (t & wmask);
101			length -= t;
102			TLOOP1(*dst++ = *src++);
103		}
104		/*
105		 * Copy whole words, then mop up any trailing bytes.
106		 */
107		t = length / wsize;
108		TLOOP(*(word *)dst = *(const word *)src; src += wsize;
109		    dst += wsize);
110		t = length & wmask;
111		TLOOP(*dst++ = *src++);
112	} else {
113		/*
114		 * Copy backwards.  Otherwise essentially the same.
115		 * Alignment works as before, except that it takes
116		 * (t&wmask) bytes to align, not wsize-(t&wmask).
117		 */
118		src += length;
119		dst += length;
120		t = (int)src;
121		if ((t | (int)dst) & wmask) {
122			if ((t ^ (int)dst) & wmask || length <= wsize)
123			    t = length;
124			else
125			    t &= wmask;
126			length -= t;
127			TLOOP1(*--dst = *--src);
128		}
129		t = length / wsize;
130		TLOOP(src -= wsize; dst -= wsize;
131		    *(word *)dst = *(const word *)src);
132		t = length & wmask;
133		TLOOP(*--dst = *--src);
134	}
135    done:
136	return (dst0);
137}
138#else
139int memmove_bs;
140#endif
141