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 * 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)
38 #if 0
39 static char *sccsid = "from: @(#)bcopy.c 5.11 (Berkeley) 6/21/91";
40 #endif
41 #if 0
42 static char *rcsid = "$NetBSD: bcopy.c,v 1.2 1997/04/16 22:09:41 thorpej Exp $";
43 #endif
44 #endif /* LIBC_SCCS and not lint */
45 #include <sys/cdefs.h>
46 __FBSDID("$FreeBSD: releng/5.1/sys/powerpc/powerpc/bcopy.c 113090 2003-04-04 17:29:55Z des $");
47
48 #include <sys/param.h>
49 #ifdef _KERNEL
50 #include <sys/systm.h>
51 #else
52 #include <string.h>
53 #endif
54
55 /*
56 * sizeof(word) MUST BE A POWER OF TWO
57 * SO THAT wmask BELOW IS ALL ONES
58 */
59 typedef int word; /* "word" used for optimal copy speed */
60
61 #define wsize sizeof(word)
62 #define wmask (wsize - 1)
63
64 /*
65 * Copy a block of memory, handling overlap.
66 * This is the routine that actually implements
67 * (the portable versions of) bcopy, memcpy, and memmove.
68 */
69 void *
70 memcpy(void *dst0, const void *src0, size_t length)
71 {
72 char *dst;
73 const char *src;
74 size_t t;
75
76 dst = dst0;
77 src = src0;
78
79 if (length == 0 || dst == src) { /* nothing to do */
80 goto done;
81 }
82
83 /*
84 * Macros: loop-t-times; and loop-t-times, t>0
85 */
86 #define TLOOP(s) if (t) TLOOP1(s)
87 #define TLOOP1(s) do { s; } while (--t)
88
89 if ((unsigned long)dst < (unsigned long)src) {
90 /*
91 * Copy forward.
92 */
93 t = (int)src; /* only need low bits */
94
95 if ((t | (int)dst) & wmask) {
96 /*
97 * Try to align operands. This cannot be done
98 * unless the low bits match.
99 */
100 if ((t ^ (int)dst) & wmask || length < wsize) {
101 t = length;
102 } else {
103 t = wsize - (t & wmask);
104 }
105
106 length -= t;
107 TLOOP1(*dst++ = *src++);
108 }
109 /*
110 * Copy whole words, then mop up any trailing bytes.
111 */
112 t = length / wsize;
113 TLOOP(*(word *)dst = *(const word *)src; src += wsize;
114 dst += wsize);
115 t = length & wmask;
116 TLOOP(*dst++ = *src++);
117 } else {
118 /*
119 * Copy backwards. Otherwise essentially the same.
120 * Alignment works as before, except that it takes
121 * (t&wmask) bytes to align, not wsize-(t&wmask).
122 */
123 src += length;
124 dst += length;
125 t = (int)src;
126
127 if ((t | (int)dst) & wmask) {
128 if ((t ^ (int)dst) & wmask || length <= wsize) {
129 t = length;
130 } else {
131 t &= wmask;
132 }
133
134 length -= t;
135 TLOOP1(*--dst = *--src);
136 }
137 t = length / wsize;
138 TLOOP(src -= wsize; dst -= wsize;
139 *(word *)dst = *(const word *)src);
140 t = length & wmask;
141 TLOOP(*--dst = *--src);
142 }
143 done:
144 return (dst0);
145 }
146
147 void
148 bcopy(const void *src0, void *dst0, size_t length)
149 {
150
151 memcpy(dst0, src0, length);
152 }
153
Cache object: d0272ef860fccb985a2e9d62a34e0601
|