bcopy.c revision 1.8 1 1.8 apb /* $NetBSD: bcopy.c,v 1.8 2008/03/26 06:19:36 apb Exp $ */
2 1.1 christos
3 1.1 christos /*-
4 1.1 christos * Copyright (c) 1990, 1993
5 1.1 christos * The Regents of the University of California. All rights reserved.
6 1.1 christos *
7 1.1 christos * This code is derived from software contributed to Berkeley by
8 1.1 christos * Chris Torek.
9 1.1 christos *
10 1.1 christos * Redistribution and use in source and binary forms, with or without
11 1.1 christos * modification, are permitted provided that the following conditions
12 1.1 christos * are met:
13 1.1 christos * 1. Redistributions of source code must retain the above copyright
14 1.1 christos * notice, this list of conditions and the following disclaimer.
15 1.1 christos * 2. Redistributions in binary form must reproduce the above copyright
16 1.1 christos * notice, this list of conditions and the following disclaimer in the
17 1.1 christos * documentation and/or other materials provided with the distribution.
18 1.1 christos * 3. Neither the name of the University nor the names of its contributors
19 1.1 christos * may be used to endorse or promote products derived from this software
20 1.1 christos * without specific prior written permission.
21 1.1 christos *
22 1.1 christos * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 1.1 christos * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 1.1 christos * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 1.1 christos * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 1.1 christos * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 1.1 christos * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 1.1 christos * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 1.1 christos * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 1.1 christos * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 1.1 christos * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 1.1 christos * SUCH DAMAGE.
33 1.1 christos */
34 1.1 christos
35 1.1 christos #include <sys/cdefs.h>
36 1.1 christos #if defined(LIBC_SCCS) && !defined(lint)
37 1.1 christos #if 0
38 1.1 christos static char sccsid[] = "@(#)bcopy.c 8.1 (Berkeley) 6/4/93";
39 1.1 christos #else
40 1.8 apb __RCSID("$NetBSD: bcopy.c,v 1.8 2008/03/26 06:19:36 apb Exp $");
41 1.1 christos #endif
42 1.1 christos #endif /* LIBC_SCCS and not lint */
43 1.1 christos
44 1.1 christos #if !defined(_KERNEL) && !defined(_STANDALONE)
45 1.1 christos #include <assert.h>
46 1.1 christos #include <string.h>
47 1.1 christos #else
48 1.1 christos #include <lib/libkern/libkern.h>
49 1.1 christos #endif
50 1.1 christos
51 1.3 christos #ifdef _FORTIFY_SOURCE
52 1.3 christos #undef bcopy
53 1.3 christos #undef memcpy
54 1.3 christos #undef memmove
55 1.3 christos #endif
56 1.3 christos
57 1.4 christos #ifndef __OPTIMIZE_SIZE__
58 1.1 christos /*
59 1.1 christos * sizeof(word) MUST BE A POWER OF TWO
60 1.1 christos * SO THAT wmask BELOW IS ALL ONES
61 1.1 christos */
62 1.1 christos typedef long word; /* "word" used for optimal copy speed */
63 1.1 christos
64 1.1 christos #define wsize sizeof(word)
65 1.1 christos #define wmask (wsize - 1)
66 1.1 christos
67 1.1 christos /*
68 1.1 christos * Copy a block of memory, handling overlap.
69 1.1 christos * This is the routine that actually implements
70 1.1 christos * (the portable versions of) bcopy, memcpy, and memmove.
71 1.1 christos */
72 1.8 apb #if defined(MEMCOPY)
73 1.1 christos void *
74 1.3 christos memcpy(void *dst0, const void *src0, size_t length)
75 1.8 apb #elif defined(MEMMOVE)
76 1.1 christos void *
77 1.3 christos memmove(void *dst0, const void *src0, size_t length)
78 1.1 christos #else
79 1.1 christos void
80 1.3 christos bcopy(const void *src0, void *dst0, size_t length)
81 1.1 christos #endif
82 1.1 christos {
83 1.1 christos char *dst = dst0;
84 1.1 christos const char *src = src0;
85 1.1 christos size_t t;
86 1.1 christos unsigned long u;
87 1.1 christos
88 1.2 ross #if !defined(_KERNEL)
89 1.1 christos _DIAGASSERT(dst0 != 0);
90 1.1 christos _DIAGASSERT(src0 != 0);
91 1.2 ross #endif
92 1.1 christos
93 1.1 christos if (length == 0 || dst == src) /* nothing to do */
94 1.1 christos goto done;
95 1.1 christos
96 1.1 christos /*
97 1.1 christos * Macros: loop-t-times; and loop-t-times, t>0
98 1.1 christos */
99 1.1 christos #define TLOOP(s) if (t) TLOOP1(s)
100 1.1 christos #define TLOOP1(s) do { s; } while (--t)
101 1.1 christos
102 1.1 christos if ((unsigned long)dst < (unsigned long)src) {
103 1.1 christos /*
104 1.1 christos * Copy forward.
105 1.1 christos */
106 1.1 christos u = (unsigned long)src; /* only need low bits */
107 1.1 christos if ((u | (unsigned long)dst) & wmask) {
108 1.1 christos /*
109 1.1 christos * Try to align operands. This cannot be done
110 1.1 christos * unless the low bits match.
111 1.1 christos */
112 1.1 christos if ((u ^ (unsigned long)dst) & wmask || length < wsize)
113 1.1 christos t = length;
114 1.1 christos else
115 1.1 christos t = wsize - (size_t)(u & wmask);
116 1.1 christos length -= t;
117 1.1 christos TLOOP1(*dst++ = *src++);
118 1.1 christos }
119 1.1 christos /*
120 1.1 christos * Copy whole words, then mop up any trailing bytes.
121 1.1 christos */
122 1.1 christos t = length / wsize;
123 1.1 christos TLOOP(*(word *)(void *)dst = *(const word *)(const void *)src; src += wsize; dst += wsize);
124 1.1 christos t = length & wmask;
125 1.1 christos TLOOP(*dst++ = *src++);
126 1.1 christos } else {
127 1.1 christos /*
128 1.1 christos * Copy backwards. Otherwise essentially the same.
129 1.1 christos * Alignment works as before, except that it takes
130 1.1 christos * (t&wmask) bytes to align, not wsize-(t&wmask).
131 1.1 christos */
132 1.1 christos src += length;
133 1.1 christos dst += length;
134 1.1 christos _DIAGASSERT((unsigned long)dst >= (unsigned long)dst0);
135 1.1 christos _DIAGASSERT((unsigned long)src >= (unsigned long)src0);
136 1.1 christos u = (unsigned long)src;
137 1.1 christos if ((u | (unsigned long)dst) & wmask) {
138 1.1 christos if ((u ^ (unsigned long)dst) & wmask || length <= wsize)
139 1.1 christos t = length;
140 1.1 christos else
141 1.1 christos t = (size_t)(u & wmask);
142 1.1 christos length -= t;
143 1.1 christos TLOOP1(*--dst = *--src);
144 1.1 christos }
145 1.1 christos t = length / wsize;
146 1.1 christos TLOOP(src -= wsize; dst -= wsize; *(word *)(void *)dst = *(const word *)(const void *)src);
147 1.1 christos t = length & wmask;
148 1.1 christos TLOOP(*--dst = *--src);
149 1.1 christos }
150 1.1 christos done:
151 1.1 christos #if defined(MEMCOPY) || defined(MEMMOVE)
152 1.1 christos return (dst0);
153 1.1 christos #else
154 1.1 christos return;
155 1.1 christos #endif
156 1.1 christos }
157 1.8 apb #else /* __OPTIMIZE_SIZE__ */
158 1.8 apb #if defined(MEMCOPY)
159 1.4 christos /*
160 1.4 christos * This is designed to be small, not fast.
161 1.4 christos */
162 1.4 christos void *
163 1.4 christos memcpy(void *s1, const void *s2, size_t n)
164 1.4 christos {
165 1.4 christos const char *f = s2;
166 1.4 christos char *t = s1;
167 1.4 christos
168 1.4 christos while (n-- > 0)
169 1.4 christos *t++ = *f++;
170 1.4 christos return s1;
171 1.4 christos }
172 1.6 christos #elif defined(MEMMOVE)
173 1.4 christos /*
174 1.4 christos * This is designed to be small, not fast.
175 1.4 christos */
176 1.4 christos void *
177 1.4 christos memmove(void *s1, const void *s2, size_t n)
178 1.4 christos {
179 1.4 christos const char *f = s2;
180 1.4 christos char *t = s1;
181 1.4 christos
182 1.4 christos if (f < t) {
183 1.4 christos f += n;
184 1.4 christos t += n;
185 1.4 christos while (n-- > 0)
186 1.4 christos *--t = *--f;
187 1.4 christos } else {
188 1.4 christos while (n-- > 0)
189 1.4 christos *t++ = *f++;
190 1.4 christos }
191 1.4 christos return s1;
192 1.4 christos }
193 1.6 christos #else
194 1.6 christos /*
195 1.6 christos * This is designed to be small, not fast.
196 1.6 christos */
197 1.7 christos void
198 1.6 christos bcopy(const void *s2, void *s1, size_t n)
199 1.6 christos {
200 1.6 christos const char *f = s2;
201 1.6 christos char *t = s1;
202 1.6 christos
203 1.6 christos while (n-- > 0)
204 1.6 christos *t++ = *f++;
205 1.6 christos }
206 1.4 christos #endif
207 1.8 apb #endif /* __OPTIMIZE_SIZE__ */
208