/* $OpenBSD: memset.c,v 1.2 2000/04/25 15:24:01 mickey 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. 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 #if defined(LIBC_SCCS) && !defined(lint) #if 0 static char sccsid[] = "@(#)memset.c 8.1 (Berkeley) 6/4/93"; #else __RCSID("$NetBSD: memset.c,v 1.6 1998/03/27 05:35:47 cgd Exp $"); #endif #endif /* LIBC_SCCS and not lint */ #include #if !defined(_KERNEL) && !defined(_STANDALONE) #include #include #else #include #include #include #endif #define wsize sizeof(u_int) #define wmask (wsize - 1) #ifdef BZERO #define RETURN return #define VAL 0 #define WIDEVAL 0 void bzero(dst0, length) void *dst0; size_t length; #else #define RETURN return (dst0) #define VAL c0 #define WIDEVAL c void * memset(dst0, c0, length) 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; }