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/* $OpenBSD: memset.c,v 1.6 2009/10/27 23:59:35 deraadt Exp $ */
/* $NetBSD: memset.c,v 1.6 1998/03/27 05:35:47 cgd Exp $ */
/*-
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Mike Hibler and Chris Torek.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/types.h>
#if !defined(_KERNEL) && !defined(_STANDALONE)
#include <string.h>
#include <limits.h>
#else
#include <sys/limits.h>
#include <sys/systm.h>
#include <lib/libkern/libkern.h>
#endif
#define wsize sizeof(u_int)
#define wmask (wsize - 1)
#ifdef BZERO
#define RETURN return
#define VAL 0
#define WIDEVAL 0
void
bzero(void *dst0, size_t length)
#else
#define RETURN return (dst0)
#define VAL c0
#define WIDEVAL c
void *
memset(void *dst0, int c0, size_t length)
#endif
{
size_t t;
#ifndef BZERO
u_int c;
#endif
u_char *dst;
dst = dst0;
/*
* If not enough words, just fill bytes. A length >= 2 words
* guarantees that at least one of them is `complete' after
* any necessary alignment. For instance:
*
* |-----------|-----------|-----------|
* |00|01|02|03|04|05|06|07|08|09|0A|00|
* ^---------------------^
* dst dst+length-1
*
* but we use a minimum of 3 here since the overhead of the code
* to do word writes is substantial.
*/
if (length < 3 * wsize) {
while (length != 0) {
*dst++ = VAL;
--length;
}
RETURN;
}
#ifndef BZERO
if ((c = (u_char)c0) != 0) { /* Fill the word. */
c = (c << 8) | c; /* u_int is 16 bits. */
#if UINT_MAX > 0xffff
c = (c << 16) | c; /* u_int is 32 bits. */
#endif
#if UINT_MAX > 0xffffffff
c = (c << 32) | c; /* u_int is 64 bits. */
#endif
}
#endif
/* Align destination by filling in bytes. */
if ((t = (u_long)dst & wmask) != 0) {
t = wsize - t;
length -= t;
do {
*dst++ = VAL;
} while (--t != 0);
}
/* Fill words. Length was >= 2*words so we know t >= 1 here. */
t = length / wsize;
do {
*(u_int *)dst = WIDEVAL;
dst += wsize;
} while (--t != 0);
/* Mop up trailing bytes, if any. */
t = length & wmask;
if (t != 0)
do {
*dst++ = VAL;
} while (--t != 0);
RETURN;
}
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