2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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.
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
37 #if defined(LIBC_SCCS) && !defined(lint)
38 static char sccsid[] = "@(#)bcopy.c 8.1 (Berkeley) 6/4/93";
39 #endif /* LIBC_SCCS and not lint */
41 static const char rcsid[] =
42 "$FreeBSD: src/lib/libc/string/bcopy.c,v 1.1.1.1.14.1 2001/07/09 23:30:03 obrien Exp $";
45 #include <sys/cdefs.h>
49 * sizeof(word) MUST BE A POWER OF TWO
50 * SO THAT wmask BELOW IS ALL ONES
52 typedef int word; /* "word" used for optimal copy speed */
54 #define wsize sizeof(word)
55 #define wmask (wsize - 1)
58 * Copy a block of memory, handling overlap.
59 * This is the routine that actually implements
60 * (the portable versions of) bcopy, memcpy, and memmove.
64 memcpy(dst0, src0, length)
68 memmove(dst0, src0, length)
71 bcopy(src0, dst0, length)
76 register size_t length;
78 register char *dst = dst0;
79 register const char *src = src0;
82 if (length == 0 || dst == src) /* nothing to do */
86 * Macros: loop-t-times; and loop-t-times, t>0
88 #define TLOOP(s) if (t) TLOOP1(s)
89 #define TLOOP1(s) do { s; } while (--t)
91 if ((unsigned long)dst < (unsigned long)src) {
95 t = (int)src; /* only need low bits */
96 if ((t | (int)dst) & wmask) {
98 * Try to align operands. This cannot be done
99 * unless the low bits match.
101 if ((t ^ (int)dst) & wmask || length < wsize)
104 t = wsize - (t & wmask);
106 TLOOP1(*dst++ = *src++);
109 * Copy whole words, then mop up any trailing bytes.
112 TLOOP(*(word *)dst = *(word *)src; src += wsize; dst += wsize);
114 TLOOP(*dst++ = *src++);
117 * Copy backwards. Otherwise essentially the same.
118 * Alignment works as before, except that it takes
119 * (t&wmask) bytes to align, not wsize-(t&wmask).
124 if ((t | (int)dst) & wmask) {
125 if ((t ^ (int)dst) & wmask || length <= wsize)
130 TLOOP1(*--dst = *--src);
133 TLOOP(src -= wsize; dst -= wsize; *(word *)dst = *(word *)src);
135 TLOOP(*--dst = *--src);
138 #if defined(MEMCOPY) || defined(MEMMOVE)