1 /* $NetBSD: bcopy.c,v 1.11 2014/04/16 20:39:55 joerg Exp $ */
2
3 /*-
4 * Copyright (c) 1990, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Chris Torek.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #include <sys/cdefs.h>
36 #if defined(LIBC_SCCS) && !defined(lint)
37 #if 0
38 static char sccsid[] = "@(#)bcopy.c 8.1 (Berkeley) 6/4/93";
39 #else
40 __RCSID("$NetBSD: bcopy.c,v 1.11 2014/04/16 20:39:55 joerg Exp $");
41 #endif
42 #endif /* LIBC_SCCS and not lint */
43
44 #if !defined(_KERNEL) && !defined(_STANDALONE)
45 #include <assert.h>
46 #include <string.h>
47 #else
48 #include <lib/libkern/libkern.h>
49 #if !defined(MEMCOPY) && defined(_STANDALONE)
50 #include <lib/libsa/stand.h>
51 #endif
52 #endif
53
54 #if defined(_FORTIFY_SOURCE) || defined(_STANDALONE) || defined(_KERNEL)
55 #undef bcopy
56 #undef memcpy
57 #undef memmove
58 #endif
59
60 #ifndef __OPTIMIZE_SIZE__
61 /*
62 * sizeof(word) MUST BE A POWER OF TWO
63 * SO THAT wmask BELOW IS ALL ONES
64 */
65 typedef long word; /* "word" used for optimal copy speed */
66
67 #define wsize sizeof(word)
68 #define wmask (wsize - 1)
69
70 /*
71 * Copy a block of memory, handling overlap.
72 * This is the routine that actually implements
73 * (the portable versions of) bcopy, memcpy, and memmove.
74 */
75 #if defined(MEMCOPY)
76 void *
memcpy(void * dst0,const void * src0,size_t length)77 memcpy(void *dst0, const void *src0, size_t length)
78 #elif defined(MEMMOVE)
79 void *
80 memmove(void *dst0, const void *src0, size_t length)
81 #else
82 void
83 bcopy(const void *src0, void *dst0, size_t length)
84 #endif
85 {
86 char *dst = dst0;
87 const char *src = src0;
88 size_t t;
89 unsigned long u;
90
91 #if !defined(_KERNEL)
92 _DIAGASSERT((dst0 && src0) || length == 0);
93 #endif
94
95 if (length == 0 || dst == src) /* nothing to do */
96 goto done;
97
98 /*
99 * Macros: loop-t-times; and loop-t-times, t>0
100 */
101 #define TLOOP(s) if (t) TLOOP1(s)
102 #define TLOOP1(s) do { s; } while (--t)
103
104 if ((unsigned long)dst < (unsigned long)src) {
105 /*
106 * Copy forward.
107 */
108 u = (unsigned long)src; /* only need low bits */
109 if ((u | (unsigned long)dst) & wmask) {
110 /*
111 * Try to align operands. This cannot be done
112 * unless the low bits match.
113 */
114 if ((u ^ (unsigned long)dst) & wmask || length < wsize)
115 t = length;
116 else
117 t = wsize - (size_t)(u & wmask);
118 length -= t;
119 TLOOP1(*dst++ = *src++);
120 }
121 /*
122 * Copy whole words, then mop up any trailing bytes.
123 */
124 t = length / wsize;
125 TLOOP(*(word *)(void *)dst = *(const word *)(const void *)src; src += wsize; dst += wsize);
126 t = length & wmask;
127 TLOOP(*dst++ = *src++);
128 } else {
129 /*
130 * Copy backwards. Otherwise essentially the same.
131 * Alignment works as before, except that it takes
132 * (t&wmask) bytes to align, not wsize-(t&wmask).
133 */
134 src += length;
135 dst += length;
136 _DIAGASSERT((unsigned long)dst >= (unsigned long)dst0);
137 _DIAGASSERT((unsigned long)src >= (unsigned long)src0);
138 u = (unsigned long)src;
139 if ((u | (unsigned long)dst) & wmask) {
140 if ((u ^ (unsigned long)dst) & wmask || length <= wsize)
141 t = length;
142 else
143 t = (size_t)(u & wmask);
144 length -= t;
145 TLOOP1(*--dst = *--src);
146 }
147 t = length / wsize;
148 TLOOP(src -= wsize; dst -= wsize; *(word *)(void *)dst = *(const word *)(const void *)src);
149 t = length & wmask;
150 TLOOP(*--dst = *--src);
151 }
152 done:
153 #if defined(MEMCOPY) || defined(MEMMOVE)
154 return (dst0);
155 #else
156 return;
157 #endif
158 }
159 #else /* __OPTIMIZE_SIZE__ */
160 #if defined(MEMCOPY)
161 /*
162 * This is designed to be small, not fast.
163 */
164 void *
memcpy(void * s1,const void * s2,size_t n)165 memcpy(void *s1, const void *s2, size_t n)
166 {
167 const char *f = s2;
168 char *t = s1;
169
170 while (n-- > 0)
171 *t++ = *f++;
172 return s1;
173 }
174 #elif defined(MEMMOVE)
175 /*
176 * This is designed to be small, not fast.
177 */
178 void *
memmove(void * s1,const void * s2,size_t n)179 memmove(void *s1, const void *s2, size_t n)
180 {
181 const char *f = s2;
182 char *t = s1;
183
184 if (f < t) {
185 f += n;
186 t += n;
187 while (n-- > 0)
188 *--t = *--f;
189 } else {
190 while (n-- > 0)
191 *t++ = *f++;
192 }
193 return s1;
194 }
195 #else
196 /*
197 * This is designed to be small, not fast.
198 */
199 void
bcopy(const void * s2,void * s1,size_t n)200 bcopy(const void *s2, void *s1, size_t n)
201 {
202 const char *f = s2;
203 char *t = s1;
204
205 while (n-- > 0)
206 *t++ = *f++;
207 }
208 #endif
209 #endif /* __OPTIMIZE_SIZE__ */
210