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 * 4. 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 "strings.h"
34#include <sys/types.h>
35
36#define	wsize	sizeof(u_int)
37#define	wmask	(wsize - 1)
38
39__attribute__((visibility("hidden")))
40void
41bzero(void *dst0, size_t length)
42{
43    return (void)memset(dst0, 0, length);
44}
45
46#define	RETURN	return (dst0)
47#define	VAL	c0
48#define	WIDEVAL	c
49
50__attribute__((visibility("hidden")))
51void *
52memset(void *dst0, int c0, size_t length)
53{
54	size_t t;
55	u_int c;
56	u_char *dst;
57
58	dst = dst0;
59	/*
60	 * If not enough words, just fill bytes.  A length >= 2 words
61	 * guarantees that at least one of them is `complete' after
62	 * any necessary alignment.  For instance:
63	 *
64	 *	|-----------|-----------|-----------|
65	 *	|00|01|02|03|04|05|06|07|08|09|0A|00|
66	 *	          ^---------------------^
67	 *		 dst		 dst+length-1
68	 *
69	 * but we use a minimum of 3 here since the overhead of the code
70	 * to do word writes is substantial.
71	 */
72	if (length < 3 * wsize) {
73		while (length != 0) {
74			*dst++ = VAL;
75			--length;
76		}
77		RETURN;
78	}
79
80	if ((c = (u_char)c0) != 0) {	/* Fill the word. */
81		c = (c << 8) | c;	/* u_int is 16 bits. */
82#if UINT_MAX > 0xffff
83		c = (c << 16) | c;	/* u_int is 32 bits. */
84#endif
85#if UINT_MAX > 0xffffffff
86		c = (c << 32) | c;	/* u_int is 64 bits. */
87#endif
88	}
89	/* Align destination by filling in bytes. */
90	if ((t = (long)dst & wmask) != 0) {
91		t = wsize - t;
92		length -= t;
93		do {
94			*dst++ = VAL;
95		} while (--t != 0);
96	}
97
98	/* Fill words.  Length was >= 2*words so we know t >= 1 here. */
99	t = length / wsize;
100	do {
101		*(u_int *)dst = WIDEVAL;
102		dst += wsize;
103	} while (--t != 0);
104
105	/* Mop up trailing bytes, if any. */
106	t = length & wmask;
107	if (t != 0)
108		do {
109			*dst++ = VAL;
110		} while (--t != 0);
111	RETURN;
112}
113