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
50void
51bzero(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
59void *
60memset(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