memset.c revision 1.11.4.1
1 /* $NetBSD: memset.c,v 1.11.4.1 2019/06/10 21:41:07 christos 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 1.11.4.1 2019/06/10 21:41:07 christos 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 #if defined(BZERO) && defined(_STANDALONE) 53 #include <lib/libsa/stand.h> 54 #endif 55 #include <machine/limits.h> 56 #endif 57 58 #define wsize sizeof(u_int) 59 #define wmask (wsize - 1) 60 61 #ifdef _FORTIFY_SOURCE 62 #undef bzero 63 #endif 64 #undef memset 65 66 #ifndef __OPTIMIZE_SIZE__ 67 #ifdef BZERO 68 #define RETURN return 69 #define VAL 0 70 #define WIDEVAL 0 71 72 void 73 bzero(void *dst0, size_t length) 74 #else 75 #define RETURN return (dst0) 76 #define VAL c0 77 #define WIDEVAL c 78 79 #if defined(__ARM_EABI__) 80 void __aeabi_memset(void *, size_t, int); 81 void __aeabi_memclr(void *, size_t); 82 83 __strong_alias(__aeabi_memset4, __aeabi_memset) 84 __strong_alias(__aeabi_memset8, __aeabi_memset) 85 86 void 87 __aeabi_memset(void *dst0, size_t length, int c) 88 { 89 memset(dst0, c, length); 90 } 91 92 void 93 __aeabi_memclr(void *dst0, size_t length) 94 { 95 memset(dst0, 0, length); 96 } 97 #endif 98 99 void * 100 memset(void *dst0, int c0, size_t length) 101 #endif 102 { 103 size_t t; 104 #ifndef BZERO 105 u_int c; 106 #endif 107 u_char *dst; 108 109 dst = dst0; 110 /* 111 * If not enough words, just fill bytes. A length >= 2 words 112 * guarantees that at least one of them is `complete' after 113 * any necessary alignment. For instance: 114 * 115 * |-----------|-----------|-----------| 116 * |00|01|02|03|04|05|06|07|08|09|0A|00| 117 * ^---------------------^ 118 * dst dst+length-1 119 * 120 * but we use a minimum of 3 here since the overhead of the code 121 * to do word writes is substantial. 122 */ 123 if (length < 3 * wsize) { 124 while (length != 0) { 125 *dst++ = VAL; 126 --length; 127 } 128 RETURN; 129 } 130 131 #ifndef BZERO 132 if ((c = (u_char)c0) != 0) { /* Fill the word. */ 133 c = (c << 8) | c; /* u_int is 16 bits. */ 134 #if UINT_MAX > 0xffff 135 c = (c << 16) | c; /* u_int is 32 bits. */ 136 #endif 137 #if UINT_MAX > 0xffffffff 138 c = (c << 32) | c; /* u_int is 64 bits. */ 139 #endif 140 } 141 #endif 142 /* Align destination by filling in bytes. */ 143 if ((t = (size_t)((u_long)dst & wmask)) != 0) { 144 t = wsize - t; 145 length -= t; 146 do { 147 *dst++ = VAL; 148 } while (--t != 0); 149 } 150 151 /* Fill words. Length was >= 2*words so we know t >= 1 here. */ 152 t = length / wsize; 153 do { 154 *(u_int *)(void *)dst = WIDEVAL; 155 dst += wsize; 156 } while (--t != 0); 157 158 /* Mop up trailing bytes, if any. */ 159 t = length & wmask; 160 if (t != 0) 161 do { 162 *dst++ = VAL; 163 } while (--t != 0); 164 RETURN; 165 } 166 #else /* __OPTIMIZE_SIZE__ */ 167 #ifdef BZERO 168 void 169 bzero(void *dstv, size_t length) 170 { 171 u_char *dst = dstv; 172 while (length-- > 0) 173 *dst++ = 0; 174 } 175 #else 176 void * 177 memset(void *dstv, int c, size_t length) 178 { 179 u_char *dst = dstv; 180 while (length-- > 0) 181 *dst++ = c; 182 return dstv; 183 } 184 #endif /* BZERO */ 185 #endif /* __OPTIMIZE_SIZE__ */ 186
Indexes created Sun Sep 21 20:09:37 GMT 2025