129 lines
3.5 KiB
C
129 lines
3.5 KiB
C
/*-
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Mike Hibler and Chris Torek.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "@(#)memset.c 8.1 (Berkeley) 6/4/93";
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#endif /* LIBC_SCCS and not lint */
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.h>
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#include <limits.h>
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#define wsize sizeof(u_int)
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#define wmask (wsize - 1)
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#ifdef BZERO
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#include <strings.h>
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#define RETURN return
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#define VAL 0
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#define WIDEVAL 0
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void
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bzero(void *dst0, size_t length)
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#else
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#include <string.h>
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#define RETURN return (dst0)
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#define VAL c0
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#define WIDEVAL c
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void *
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memset(void *dst0, int c0, size_t length)
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#endif
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{
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size_t t;
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#ifndef BZERO
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u_int c;
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#endif
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u_char *dst;
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dst = dst0;
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/*
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* If not enough words, just fill bytes. A length >= 2 words
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* guarantees that at least one of them is `complete' after
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* any necessary alignment. For instance:
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*
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* |-----------|-----------|-----------|
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* |00|01|02|03|04|05|06|07|08|09|0A|00|
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* ^---------------------^
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* dst dst+length-1
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*
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* but we use a minimum of 3 here since the overhead of the code
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* to do word writes is substantial.
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*/
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if (length < 3 * wsize) {
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while (length != 0) {
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*dst++ = VAL;
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--length;
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}
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RETURN;
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}
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#ifndef BZERO
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if ((c = (u_char)c0) != 0) { /* Fill the word. */
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c = (c << 8) | c; /* u_int is 16 bits. */
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#if UINT_MAX > 0xffff
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c = (c << 16) | c; /* u_int is 32 bits. */
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#endif
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#if UINT_MAX > 0xffffffff
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c = (c << 32) | c; /* u_int is 64 bits. */
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#endif
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}
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#endif
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/* Align destination by filling in bytes. */
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if ((t = (long)dst & wmask) != 0) {
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t = wsize - t;
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length -= t;
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do {
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*dst++ = VAL;
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} while (--t != 0);
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}
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/* Fill words. Length was >= 2*words so we know t >= 1 here. */
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t = length / wsize;
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do {
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*(u_int *)dst = WIDEVAL;
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dst += wsize;
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} while (--t != 0);
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/* Mop up trailing bytes, if any. */
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t = length & wmask;
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if (t != 0)
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do {
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*dst++ = VAL;
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} while (--t != 0);
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RETURN;
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}
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