1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
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#if defined(LIBC_SCCS) && !defined(lint)
36static char sccsid[] = "@(#)memset.c	8.1 (Berkeley) 6/4/93";
37#endif /* LIBC_SCCS and not lint */
38#include <sys/cdefs.h>
39__FBSDID("$FreeBSD$");
40
41#include <sys/types.h>
42
43#include <limits.h>
44
45#define	wsize	sizeof(u_int)
46#define	wmask	(wsize - 1)
47
48#ifdef BZERO
49#include <strings.h>
50
51#define	RETURN	return
52#define	VAL	0
53#define	WIDEVAL	0
54
55void
56bzero(void *dst0, size_t length)
57#else
58#include <string.h>
59
60#define	RETURN	return (dst0)
61#define	VAL	c0
62#define	WIDEVAL	c
63
64void *
65memset(void *dst0, int c0, size_t length)
66#endif
67{
68	size_t t;
69#ifndef BZERO
70	u_int c;
71#endif
72	u_char *dst;
73
74	dst = dst0;
75	/*
76	 * If not enough words, just fill bytes.  A length >= 2 words
77	 * guarantees that at least one of them is `complete' after
78	 * any necessary alignment.  For instance:
79	 *
80	 *	|-----------|-----------|-----------|
81	 *	|00|01|02|03|04|05|06|07|08|09|0A|00|
82	 *	          ^---------------------^
83	 *		 dst		 dst+length-1
84	 *
85	 * but we use a minimum of 3 here since the overhead of the code
86	 * to do word writes is substantial.
87	 */
88	if (length < 3 * wsize) {
89		while (length != 0) {
90			*dst++ = VAL;
91			--length;
92		}
93		RETURN;
94	}
95
96#ifndef BZERO
97	if ((c = (u_char)c0) != 0) {	/* Fill the word. */
98		c = (c << 8) | c;	/* u_int is 16 bits. */
99#if UINT_MAX > 0xffff
100		c = (c << 16) | c;	/* u_int is 32 bits. */
101#endif
102#if UINT_MAX > 0xffffffff
103		c = (c << 32) | c;	/* u_int is 64 bits. */
104#endif
105	}
106#endif
107	/* Align destination by filling in bytes. */
108	if ((t = (long)dst & wmask) != 0) {
109		t = wsize - t;
110		length -= t;
111		do {
112			*dst++ = VAL;
113		} while (--t != 0);
114	}
115
116	/* Fill words.  Length was >= 2*words so we know t >= 1 here. */
117	t = length / wsize;
118	do {
119		*(u_int *)dst = WIDEVAL;
120		dst += wsize;
121	} while (--t != 0);
122
123	/* Mop up trailing bytes, if any. */
124	t = length & wmask;
125	if (t != 0)
126		do {
127			*dst++ = VAL;
128		} while (--t != 0);
129	RETURN;
130}
131