1/*	$NetBSD: memset.c,v 1.8 2009/03/18 12:25:06 tsutsui Exp $	*/
2
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#include <sys/cdefs.h>
36#if defined(LIBC_SCCS) && !defined(lint)
37#if 0
38static char sccsid[] = "@(#)memset.c	8.1 (Berkeley) 6/4/93";
39#else
40__RCSID("$NetBSD: memset.c,v 1.8 2009/03/18 12:25:06 tsutsui Exp $");
41#endif
42#endif /* LIBC_SCCS and not lint */
43
44#include <sys/types.h>
45
46#if !defined(_KERNEL) && !defined(_STANDALONE)
47#include <assert.h>
48#include <limits.h>
49#include <string.h>
50#else
51#include <lib/libkern/libkern.h>
52#if defined(BZERO) && defined(_STANDALONE)
53#include <lib/libsa/stand.h>
54#endif
55#include <machine/limits.h>
56#endif
57
58#define	wsize	sizeof(u_int)
59#define	wmask	(wsize - 1)
60
61#ifdef _FORTIFY_SOURCE
62#undef bzero
63#endif
64#undef memset
65
66#ifndef __OPTIMIZE_SIZE__
67#ifdef BZERO
68#define	RETURN	return
69#define	VAL	0
70#define	WIDEVAL	0
71
72void
73bzero(void *dst0, size_t length)
74#else
75#define	RETURN	return (dst0)
76#define	VAL	c0
77#define	WIDEVAL	c
78
79void *
80memset(void *dst0, int c0, size_t length)
81#endif
82{
83	size_t t;
84#ifndef BZERO
85	u_int c;
86#endif
87	u_char *dst;
88
89	_DIAGASSERT(dst0 != 0);
90
91	dst = dst0;
92	/*
93	 * If not enough words, just fill bytes.  A length >= 2 words
94	 * guarantees that at least one of them is `complete' after
95	 * any necessary alignment.  For instance:
96	 *
97	 *	|-----------|-----------|-----------|
98	 *	|00|01|02|03|04|05|06|07|08|09|0A|00|
99	 *	          ^---------------------^
100	 *		 dst		 dst+length-1
101	 *
102	 * but we use a minimum of 3 here since the overhead of the code
103	 * to do word writes is substantial.
104	 */
105	if (length < 3 * wsize) {
106		while (length != 0) {
107			*dst++ = VAL;
108			--length;
109		}
110		RETURN;
111	}
112
113#ifndef BZERO
114	if ((c = (u_char)c0) != 0) {	/* Fill the word. */
115		c = (c << 8) | c;	/* u_int is 16 bits. */
116#if UINT_MAX > 0xffff
117		c = (c << 16) | c;	/* u_int is 32 bits. */
118#endif
119#if UINT_MAX > 0xffffffff
120		c = (c << 32) | c;	/* u_int is 64 bits. */
121#endif
122	}
123#endif
124	/* Align destination by filling in bytes. */
125	if ((t = (size_t)((u_long)dst & wmask)) != 0) {
126		t = wsize - t;
127		length -= t;
128		do {
129			*dst++ = VAL;
130		} while (--t != 0);
131	}
132
133	/* Fill words.  Length was >= 2*words so we know t >= 1 here. */
134	t = length / wsize;
135	do {
136		*(u_int *)(void *)dst = WIDEVAL;
137		dst += wsize;
138	} while (--t != 0);
139
140	/* Mop up trailing bytes, if any. */
141	t = length & wmask;
142	if (t != 0)
143		do {
144			*dst++ = VAL;
145		} while (--t != 0);
146	RETURN;
147}
148#else /* __OPTIMIZE_SIZE__ */
149#ifdef BZERO
150void
151bzero(void *dstv, size_t length)
152{
153	u_char *dst = dstv;
154	while (length-- > 0)
155		*dst++ = 0;
156}
157#else
158void *
159memset(void *dstv, int c, size_t length)
160{
161	u_char *dst = dstv;
162	while (length-- > 0)
163		*dst++ = c;
164	return dstv;
165}
166#endif /* BZERO */
167#endif /* __OPTIMIZE_SIZE__ */
168