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. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
35
36 #include <sys/types.h>
37
38 #include <limits.h>
39
40 #define wsize sizeof(u_int)
41 #define wmask (wsize - 1)
42
43 #ifdef BZERO
44 #include <strings.h>
45
46 #define RETURN return
47 #define VAL 0
48 #define WIDEVAL 0
49
50 void
bzero(void * dst0,size_t length)51 bzero(void *dst0, size_t length)
52 #else
53 #include <string.h>
54
55 #define RETURN return (dst0)
56 #define VAL c0
57 #define WIDEVAL c
58
59 void *
60 memset(void *dst0, int c0, size_t length)
61 #endif
62 {
63 size_t t;
64 #ifndef BZERO
65 u_int c;
66 #endif
67 u_char *dst;
68
69 dst = dst0;
70 /*
71 * If not enough words, just fill bytes. A length >= 2 words
72 * guarantees that at least one of them is `complete' after
73 * any necessary alignment. For instance:
74 *
75 * |-----------|-----------|-----------|
76 * |00|01|02|03|04|05|06|07|08|09|0A|00|
77 * ^---------------------^
78 * dst dst+length-1
79 *
80 * but we use a minimum of 3 here since the overhead of the code
81 * to do word writes is substantial.
82 */
83 if (length < 3 * wsize) {
84 while (length != 0) {
85 *dst++ = VAL;
86 --length;
87 }
88 RETURN;
89 }
90
91 #ifndef BZERO
92 if ((c = (u_char)c0) != 0) { /* Fill the word. */
93 c = (c << 8) | c; /* u_int is 16 bits. */
94 #if UINT_MAX > 0xffff
95 c = (c << 16) | c; /* u_int is 32 bits. */
96 #endif
97 #if UINT_MAX > 0xffffffff
98 c = (c << 32) | c; /* u_int is 64 bits. */
99 #endif
100 }
101 #endif
102 /* Align destination by filling in bytes. */
103 if ((t = (long)dst & wmask) != 0) {
104 t = wsize - t;
105 length -= t;
106 do {
107 *dst++ = VAL;
108 } while (--t != 0);
109 }
110
111 /* Fill words. Length was >= 2*words so we know t >= 1 here. */
112 t = length / wsize;
113 do {
114 *(u_int *)dst = WIDEVAL;
115 dst += wsize;
116 } while (--t != 0);
117
118 /* Mop up trailing bytes, if any. */
119 t = length & wmask;
120 if (t != 0)
121 do {
122 *dst++ = VAL;
123 } while (--t != 0);
124 RETURN;
125 }
126