1/*	$NetBSD: memset.c,v 1.12 2019/03/30 10:18:03 jmcneill 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 1.12 2019/03/30 10:18:03 jmcneill 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
79#if defined(__ARM_EABI__)
80void __aeabi_memset(void *, size_t, int);
81void __aeabi_memclr(void *, size_t);
82
83__strong_alias(__aeabi_memset4, __aeabi_memset)
84__strong_alias(__aeabi_memset8, __aeabi_memset)
85
86void
87__aeabi_memset(void *dst0, size_t length, int c)
88{
89	memset(dst0, c, length);
90}
91
92void
93__aeabi_memclr(void *dst0, size_t length)
94{
95	memset(dst0, 0, length);
96}
97#endif
98
99void *
100memset(void *dst0, int c0, size_t length)
101#endif
102{
103	size_t t;
104#ifndef BZERO
105	u_int c;
106#endif
107	u_char *dst;
108
109	dst = dst0;
110	/*
111	 * If not enough words, just fill bytes.  A length >= 2 words
112	 * guarantees that at least one of them is `complete' after
113	 * any necessary alignment.  For instance:
114	 *
115	 *	|-----------|-----------|-----------|
116	 *	|00|01|02|03|04|05|06|07|08|09|0A|00|
117	 *	          ^---------------------^
118	 *		 dst		 dst+length-1
119	 *
120	 * but we use a minimum of 3 here since the overhead of the code
121	 * to do word writes is substantial.
122	 */
123	if (length < 3 * wsize) {
124		while (length != 0) {
125			*dst++ = VAL;
126			--length;
127		}
128		RETURN;
129	}
130
131#ifndef BZERO
132	if ((c = (u_char)c0) != 0) {	/* Fill the word. */
133		c = (c << 8) | c;	/* u_int is 16 bits. */
134#if UINT_MAX > 0xffff
135		c = (c << 16) | c;	/* u_int is 32 bits. */
136#endif
137#if UINT_MAX > 0xffffffff
138		c = (c << 32) | c;	/* u_int is 64 bits. */
139#endif
140	}
141#endif
142	/* Align destination by filling in bytes. */
143	if ((t = (size_t)((u_long)dst & wmask)) != 0) {
144		t = wsize - t;
145		length -= t;
146		do {
147			*dst++ = VAL;
148		} while (--t != 0);
149	}
150
151	/* Fill words.  Length was >= 2*words so we know t >= 1 here. */
152	t = length / wsize;
153	do {
154		*(u_int *)(void *)dst = WIDEVAL;
155		dst += wsize;
156	} while (--t != 0);
157
158	/* Mop up trailing bytes, if any. */
159	t = length & wmask;
160	if (t != 0)
161		do {
162			*dst++ = VAL;
163		} while (--t != 0);
164	RETURN;
165}
166#else /* __OPTIMIZE_SIZE__ */
167#ifdef BZERO
168void
169bzero(void *dstv, size_t length)
170{
171	u_char *dst = dstv;
172	while (length-- > 0)
173		*dst++ = 0;
174}
175#else
176void *
177memset(void *dstv, int c, size_t length)
178{
179	u_char *dst = dstv;
180	while (length-- > 0)
181		*dst++ = c;
182	return dstv;
183}
184#endif /* BZERO */
185#endif /* __OPTIMIZE_SIZE__ */
186