1 /*-
2 * Copyright (c) 1990 The Regents of the University of California.
3 * 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 * 4. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 #if defined(LIBC_SCCS) && !defined(lint)
34 #if 0
35 static char *sccsid = "from: @(#)bcopy.c 5.11 (Berkeley) 6/21/91";
36 #endif
37 #if 0
38 static char *rcsid = "$NetBSD: bcopy.c,v 1.2 1997/04/16 22:09:41 thorpej Exp $";
39 #endif
40 #endif /* LIBC_SCCS and not lint */
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD: releng/6.2/sys/powerpc/powerpc/bcopy.c 127977 2004-04-07 05:00:01Z imp $");
43
44 #include <sys/param.h>
45 #ifdef _KERNEL
46 #include <sys/systm.h>
47 #else
48 #include <string.h>
49 #endif
50
51 /*
52 * sizeof(word) MUST BE A POWER OF TWO
53 * SO THAT wmask BELOW IS ALL ONES
54 */
55 typedef int word; /* "word" used for optimal copy speed */
56
57 #define wsize sizeof(word)
58 #define wmask (wsize - 1)
59
60 /*
61 * Copy a block of memory, handling overlap.
62 * This is the routine that actually implements
63 * (the portable versions of) bcopy, memcpy, and memmove.
64 */
65 void *
66 memcpy(void *dst0, const void *src0, size_t length)
67 {
68 char *dst;
69 const char *src;
70 size_t t;
71
72 dst = dst0;
73 src = src0;
74
75 if (length == 0 || dst == src) { /* nothing to do */
76 goto done;
77 }
78
79 /*
80 * Macros: loop-t-times; and loop-t-times, t>0
81 */
82 #define TLOOP(s) if (t) TLOOP1(s)
83 #define TLOOP1(s) do { s; } while (--t)
84
85 if ((unsigned long)dst < (unsigned long)src) {
86 /*
87 * Copy forward.
88 */
89 t = (int)src; /* only need low bits */
90
91 if ((t | (int)dst) & wmask) {
92 /*
93 * Try to align operands. This cannot be done
94 * unless the low bits match.
95 */
96 if ((t ^ (int)dst) & wmask || length < wsize) {
97 t = length;
98 } else {
99 t = wsize - (t & wmask);
100 }
101
102 length -= t;
103 TLOOP1(*dst++ = *src++);
104 }
105 /*
106 * Copy whole words, then mop up any trailing bytes.
107 */
108 t = length / wsize;
109 TLOOP(*(word *)dst = *(const word *)src; src += wsize;
110 dst += wsize);
111 t = length & wmask;
112 TLOOP(*dst++ = *src++);
113 } else {
114 /*
115 * Copy backwards. Otherwise essentially the same.
116 * Alignment works as before, except that it takes
117 * (t&wmask) bytes to align, not wsize-(t&wmask).
118 */
119 src += length;
120 dst += length;
121 t = (int)src;
122
123 if ((t | (int)dst) & wmask) {
124 if ((t ^ (int)dst) & wmask || length <= wsize) {
125 t = length;
126 } else {
127 t &= wmask;
128 }
129
130 length -= t;
131 TLOOP1(*--dst = *--src);
132 }
133 t = length / wsize;
134 TLOOP(src -= wsize; dst -= wsize;
135 *(word *)dst = *(const word *)src);
136 t = length & wmask;
137 TLOOP(*--dst = *--src);
138 }
139 done:
140 return (dst0);
141 }
142
143 void
144 bcopy(const void *src0, void *dst0, size_t length)
145 {
146
147 memcpy(dst0, src0, length);
148 }
149
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