8322 nl: misleading-indentation
[unleashed/tickless.git] / usr / src / boot / lib / libc / string / memset.c
blobad0d513933fe24a87c468b7f5917c819eaf8c9df
1 /*-
2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
6 * Mike Hibler and Chris Torek.
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.
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.
33 #if defined(LIBC_SCCS) && !defined(lint)
34 static char sccsid[] = "@(#)memset.c 8.1 (Berkeley) 6/4/93";
35 #endif /* LIBC_SCCS and not lint */
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
39 #include <sys/types.h>
41 #include <limits.h>
43 #define wsize sizeof(u_int)
44 #define wmask (wsize - 1)
46 #ifdef BZERO
47 #include <strings.h>
49 #define RETURN return
50 #define VAL 0
51 #define WIDEVAL 0
53 void
54 bzero(void *dst0, size_t length)
55 #else
56 #include <string.h>
58 #define RETURN return (dst0)
59 #define VAL c0
60 #define WIDEVAL c
62 void *
63 memset(void *dst0, int c0, size_t length)
64 #endif
66 size_t t;
67 #ifndef BZERO
68 u_int c;
69 #endif
70 u_char *dst;
72 dst = dst0;
74 * If not enough words, just fill bytes. A length >= 2 words
75 * guarantees that at least one of them is `complete' after
76 * any necessary alignment. For instance:
78 * |-----------|-----------|-----------|
79 * |00|01|02|03|04|05|06|07|08|09|0A|00|
80 * ^---------------------^
81 * dst dst+length-1
83 * but we use a minimum of 3 here since the overhead of the code
84 * to do word writes is substantial.
86 if (length < 3 * wsize) {
87 while (length != 0) {
88 *dst++ = VAL;
89 --length;
91 RETURN;
94 #ifndef BZERO
95 if ((c = (u_char)c0) != 0) { /* Fill the word. */
96 c = (c << 8) | c; /* u_int is 16 bits. */
97 #if UINT_MAX > 0xffff
98 c = (c << 16) | c; /* u_int is 32 bits. */
99 #endif
100 #if UINT_MAX > 0xffffffff
101 c = (c << 32) | c; /* u_int is 64 bits. */
102 #endif
104 #endif
105 /* Align destination by filling in bytes. */
106 if ((t = (long)dst & wmask) != 0) {
107 t = wsize - t;
108 length -= t;
109 do {
110 *dst++ = VAL;
111 } while (--t != 0);
114 /* Fill words. Length was >= 2*words so we know t >= 1 here. */
115 t = length / wsize;
116 do {
117 *(u_int *)dst = WIDEVAL;
118 dst += wsize;
119 } while (--t != 0);
121 /* Mop up trailing bytes, if any. */
122 t = length & wmask;
123 if (t != 0)
124 do {
125 *dst++ = VAL;
126 } while (--t != 0);
127 RETURN;