1 /* $NetBSD: memset.c,v 1.6 2008/03/29 14:03:22 he 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 38 static char sccsid[] = "@(#)memset.c 8.1 (Berkeley) 6/4/93"; 39 #else 40 __RCSID("$NetBSD: memset.c,v 1.6 2008/03/29 14:03:22 he 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 #include <machine/limits.h> 53 #endif 54 55 #define wsize sizeof(u_int) 56 #define wmask (wsize - 1) 57 58 #ifdef _FORTIFY_SOURCE 59 #undef bzero 60 #undef memset 61 #endif 62 63 #ifndef __OPTIMIZE_SIZE__ 64 #ifdef BZERO 65 #define RETURN return 66 #define VAL 0 67 #define WIDEVAL 0 68 69 void 70 bzero(void *dst0, size_t length) 71 #else 72 #define RETURN return (dst0) 73 #define VAL c0 74 #define WIDEVAL c 75 76 void * 77 memset(void *dst0, int c0, size_t length) 78 #endif 79 { 80 size_t t; 81 #ifndef BZERO 82 u_int c; 83 #endif 84 u_char *dst; 85 86 _DIAGASSERT(dst0 != 0); 87 88 dst = dst0; 89 /* 90 * If not enough words, just fill bytes. A length >= 2 words 91 * guarantees that at least one of them is `complete' after 92 * any necessary alignment. For instance: 93 * 94 * |-----------|-----------|-----------| 95 * |00|01|02|03|04|05|06|07|08|09|0A|00| 96 * ^---------------------^ 97 * dst dst+length-1 98 * 99 * but we use a minimum of 3 here since the overhead of the code 100 * to do word writes is substantial. 101 */ 102 if (length < 3 * wsize) { 103 while (length != 0) { 104 *dst++ = VAL; 105 --length; 106 } 107 RETURN; 108 } 109 110 #ifndef BZERO 111 if ((c = (u_char)c0) != 0) { /* Fill the word. */ 112 c = (c << 8) | c; /* u_int is 16 bits. */ 113 #if UINT_MAX > 0xffff 114 c = (c << 16) | c; /* u_int is 32 bits. */ 115 #endif 116 #if UINT_MAX > 0xffffffff 117 c = (c << 32) | c; /* u_int is 64 bits. */ 118 #endif 119 } 120 #endif 121 /* Align destination by filling in bytes. */ 122 if ((t = (size_t)((u_long)dst & wmask)) != 0) { 123 t = wsize - t; 124 length -= t; 125 do { 126 *dst++ = VAL; 127 } while (--t != 0); 128 } 129 130 /* Fill words. Length was >= 2*words so we know t >= 1 here. */ 131 t = length / wsize; 132 do { 133 *(u_int *)(void *)dst = WIDEVAL; 134 dst += wsize; 135 } while (--t != 0); 136 137 /* Mop up trailing bytes, if any. */ 138 t = length & wmask; 139 if (t != 0) 140 do { 141 *dst++ = VAL; 142 } while (--t != 0); 143 RETURN; 144 } 145 #else /* __OPTIMIZE_SIZE__ */ 146 #ifdef BZERO 147 void 148 bzero(void *dstv, size_t length) 149 { 150 u_char *dst = dstv; 151 while (length-- > 0) 152 *dst++ = 0; 153 } 154 #else 155 void * 156 memset(void *dstv, int c, size_t length) 157 { 158 u_char *dst = dstv; 159 while (length-- > 0) 160 *dst++ = c; 161 return dstv; 162 } 163 #endif /* BZERO */ 164 #endif /* __OPTIMIZE_SIZE__ */ 165