1 /*-
2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Mike Hibler and 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 #include "config.h"
38
39 #if defined(LIBC_SCCS) && !defined(lint)
40 static const char sccsid[] = "@(#)memset.c 8.1 (Berkeley) 6/4/93";
41 #endif /* LIBC_SCCS and not lint */
42 #else
43 __RCSID("$NetBSD: memset.c,v 1.2 2014/01/26 21:43:45 christos Exp $");
44 #endif
45
46 #include <sys/types.h>
47
48 #include <limits.h>
49 #include <string.h>
50
51 /*
52 * PUBLIC: #ifndef HAVE_MEMSET
53 * PUBLIC: void *memset __P((void *, int, size_t));
54 * PUBLIC: #endif
55 */
56 #define wsize sizeof(u_int)
57 #define wmask (wsize - 1)
58
59 #ifdef BZERO
60 #define RETURN return
61 #define VAL 0
62 #define WIDEVAL 0
63
64 void
bzero(dst0,length)65 bzero(dst0, length)
66 void *dst0;
67 register size_t length;
68 #else
69 #define RETURN return (dst0)
70 #define VAL c0
71 #define WIDEVAL c
72
73 void *
74 memset(void *dst0, register int c0, register size_t length)
75
76
77
78 #endif
79 {
80 register size_t t;
81 register u_int c;
82 register u_char *dst;
83
84 dst = dst0;
85 /*
86 * If not enough words, just fill bytes. A length >= 2 words
87 * guarantees that at least one of them is `complete' after
88 * any necessary alignment. For instance:
89 *
90 * |-----------|-----------|-----------|
91 * |00|01|02|03|04|05|06|07|08|09|0A|00|
92 * ^---------------------^
93 * dst dst+length-1
94 *
95 * but we use a minimum of 3 here since the overhead of the code
96 * to do word writes is substantial.
97 */
98 if (length < 3 * wsize) {
99 while (length != 0) {
100 *dst++ = VAL;
101 --length;
102 }
103 RETURN;
104 }
105
106 #ifndef BZERO
107 if ((c = (u_char)c0) != 0) { /* Fill the word. */
108 c = (c << 8) | c; /* u_int is 16 bits. */
109 #if UINT_MAX > 0xffff
110 c = (c << 16) | c; /* u_int is 32 bits. */
111 #endif
112 #if UINT_MAX > 0xffffffff
113 c = (c << 32) | c; /* u_int is 64 bits. */
114 #endif
115 }
116 #endif
117 /* Align destination by filling in bytes. */
118 if ((t = (int)dst & wmask) != 0) {
119 t = wsize - t;
120 length -= t;
121 do {
122 *dst++ = VAL;
123 } while (--t != 0);
124 }
125
126 /* Fill words. Length was >= 2*words so we know t >= 1 here. */
127 t = length / wsize;
128 do {
129 *(u_int *)dst = WIDEVAL;
130 dst += wsize;
131 } while (--t != 0);
132
133 /* Mop up trailing bytes, if any. */
134 t = length & wmask;
135 if (t != 0)
136 do {
137 *dst++ = VAL;
138 } while (--t != 0);
139 RETURN;
140 }
141