- Wrap change of entries in an InitChange/ExitChange pair (without this,
[AROS.git] / compiler / stdc / memmove.c
blob0d094b16a17ad0653b932e2013c6b9cccdc2fb86
1 /*-
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
6 * Chris Torek.
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.
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.
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 */
42 * sizeof(word) MUST BE A POWER OF TWO
43 * SO THAT wmask BELOW IS ALL ONES
45 typedef int word; /* "word" used for optimal copy speed */
47 #define wsize sizeof(word)
48 #define wmask (wsize - 1)
51 * Copy a block of memory, handling overlap.
54 /*****************************************************************************
56 NAME */
57 #include <string.h>
59 void *memmove (
61 /* SYNOPSIS */
62 void *dst0,
63 const void *src0,
64 size_t length)
66 /* FUNCTION
67 Copy a block of memory, handling overlap.
69 INPUTS
70 dst0: destination for copy
71 src0: source for copy
72 length: number of bytes to copy
74 RESULT
75 dst0
77 NOTES
79 EXAMPLE
81 BUGS
83 SEE ALSO
85 INTERNALS
87 ******************************************************************************/
89 char *dst = dst0;
90 const char *src = src0;
91 size_t t;
93 if (length == 0 || dst == src) /* nothing to do */
94 goto done;
97 * Macros: loop-t-times; and loop-t-times, t>0
99 #define TLOOP(s) if (t) TLOOP1(s)
100 #define TLOOP1(s) do { s; } while (--t)
102 if ((unsigned long)dst < (unsigned long)src) {
104 * Copy forward.
106 t = (unsigned long)src; /* only need low bits */
107 if ((t | (unsigned long)dst) & wmask) {
109 * Try to align operands. This cannot be done
110 * unless the low bits match.
112 if ((t ^ (unsigned long)dst) & wmask || length < wsize)
113 t = length;
114 else
115 t = wsize - (t & wmask);
116 length -= t;
117 TLOOP1(*dst++ = *src++);
120 * Copy whole words, then mop up any trailing bytes.
122 t = length / wsize;
123 TLOOP(*(word *)dst = *(word *)src; src += wsize; dst += wsize);
124 t = length & wmask;
125 TLOOP(*dst++ = *src++);
126 } else {
128 * Copy backwards. Otherwise essentially the same.
129 * Alignment works as before, except that it takes
130 * (t&wmask) bytes to align, not wsize-(t&wmask).
132 src += length;
133 dst += length;
134 t = (unsigned long)src;
135 if ((t | (unsigned long)dst) & wmask) {
136 if ((t ^ (unsigned long)dst) & wmask || length <= wsize)
137 t = length;
138 else
139 t &= wmask;
140 length -= t;
141 TLOOP1(*--dst = *--src);
143 t = length / wsize;
144 TLOOP(src -= wsize; dst -= wsize; *(word *)dst = *(word *)src);
145 t = length & wmask;
146 TLOOP(*--dst = *--src);
148 done:
149 return (dst0);
153 /* Provide a memcpy symbol for static link library */
154 #include <aros/system.h>
155 #include <string.h>
156 AROS_MAKE_ALIAS(memmove, memcpy);