1 /* $NetBSD: memset.c,v 1.12 2019/03/30 10:18:03 jmcneill 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 * Mike Hibler and 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[] = "@(#)memset.c 8.1 (Berkeley) 6/4/93";
39 #else
40 __RCSID("$NetBSD: memset.c,v 1.12 2019/03/30 10:18:03 jmcneill Exp $");
41 #endif
42 #endif /* LIBC_SCCS and not lint */
43
44 #include <sys/types.h>
45
46 #if !defined(_KERNEL) && !defined(_STANDALONE)
47 #include <assert.h>
48 #include <limits.h>
49 #include <string.h>
50 #else
51 #include <lib/libkern/libkern.h>
52 #if defined(BZERO) && defined(_STANDALONE)
53 #include <lib/libsa/stand.h>
54 #endif
55 #include <machine/limits.h>
56 #endif
57
58 #define wsize sizeof(u_int)
59 #define wmask (wsize - 1)
60
61 #ifdef _FORTIFY_SOURCE
62 #undef bzero
63 #endif
64 #undef memset
65
66 #ifndef __OPTIMIZE_SIZE__
67 #ifdef BZERO
68 #define RETURN return
69 #define VAL 0
70 #define WIDEVAL 0
71
72 void
bzero(void * dst0,size_t length)73 bzero(void *dst0, size_t length)
74 #else
75 #define RETURN return (dst0)
76 #define VAL c0
77 #define WIDEVAL c
78
79 #if defined(__ARM_EABI__)
80 void __aeabi_memset(void *, size_t, int);
81 void __aeabi_memclr(void *, size_t);
82
83 __strong_alias(__aeabi_memset4, __aeabi_memset)
84 __strong_alias(__aeabi_memset8, __aeabi_memset)
85
86 void
87 __aeabi_memset(void *dst0, size_t length, int c)
88 {
89 memset(dst0, c, length);
90 }
91
92 void
93 __aeabi_memclr(void *dst0, size_t length)
94 {
95 memset(dst0, 0, length);
96 }
97 #endif
98
99 void *
100 memset(void *dst0, int c0, size_t length)
101 #endif
102 {
103 size_t t;
104 #ifndef BZERO
105 u_int c;
106 #endif
107 u_char *dst;
108
109 dst = dst0;
110 /*
111 * If not enough words, just fill bytes. A length >= 2 words
112 * guarantees that at least one of them is `complete' after
113 * any necessary alignment. For instance:
114 *
115 * |-----------|-----------|-----------|
116 * |00|01|02|03|04|05|06|07|08|09|0A|00|
117 * ^---------------------^
118 * dst dst+length-1
119 *
120 * but we use a minimum of 3 here since the overhead of the code
121 * to do word writes is substantial.
122 */
123 if (length < 3 * wsize) {
124 while (length != 0) {
125 *dst++ = VAL;
126 --length;
127 }
128 RETURN;
129 }
130
131 #ifndef BZERO
132 if ((c = (u_char)c0) != 0) { /* Fill the word. */
133 c = (c << 8) | c; /* u_int is 16 bits. */
134 #if UINT_MAX > 0xffff
135 c = (c << 16) | c; /* u_int is 32 bits. */
136 #endif
137 #if UINT_MAX > 0xffffffff
138 c = (c << 32) | c; /* u_int is 64 bits. */
139 #endif
140 }
141 #endif
142 /* Align destination by filling in bytes. */
143 if ((t = (size_t)((u_long)dst & wmask)) != 0) {
144 t = wsize - t;
145 length -= t;
146 do {
147 *dst++ = VAL;
148 } while (--t != 0);
149 }
150
151 /* Fill words. Length was >= 2*words so we know t >= 1 here. */
152 t = length / wsize;
153 do {
154 *(u_int *)(void *)dst = WIDEVAL;
155 dst += wsize;
156 } while (--t != 0);
157
158 /* Mop up trailing bytes, if any. */
159 t = length & wmask;
160 if (t != 0)
161 do {
162 *dst++ = VAL;
163 } while (--t != 0);
164 RETURN;
165 }
166 #else /* __OPTIMIZE_SIZE__ */
167 #ifdef BZERO
168 void
bzero(void * dstv,size_t length)169 bzero(void *dstv, size_t length)
170 {
171 u_char *dst = dstv;
172 while (length-- > 0)
173 *dst++ = 0;
174 }
175 #else
176 void *
memset(void * dstv,int c,size_t length)177 memset(void *dstv, int c, size_t length)
178 {
179 u_char *dst = dstv;
180 while (length-- > 0)
181 *dst++ = c;
182 return dstv;
183 }
184 #endif /* BZERO */
185 #endif /* __OPTIMIZE_SIZE__ */
186