1 /*- 2 * Copyright (c) 1990, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Mike Hibler and Chris Torek. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #include "config.h" 38 39 #if defined(LIBC_SCCS) && !defined(lint) 40 static const char sccsid[] = "@(#)memset.c 8.1 (Berkeley) 6/4/93"; 41 #endif /* LIBC_SCCS and not lint */ 42 #else 43 __RCSID("$NetBSD: memset.c,v 1.2 2014/01/26 21:43:45 christos Exp $"); 44 #endif 45 46 #include <sys/types.h> 47 48 #include <limits.h> 49 #include <string.h> 50 51 /* 52 * PUBLIC: #ifndef HAVE_MEMSET 53 * PUBLIC: void *memset __P((void *, int, size_t)); 54 * PUBLIC: #endif 55 */ 56 #define wsize sizeof(u_int) 57 #define wmask (wsize - 1) 58 59 #ifdef BZERO 60 #define RETURN return 61 #define VAL 0 62 #define WIDEVAL 0 63 64 void 65 bzero(dst0, length) 66 void *dst0; 67 register size_t length; 68 #else 69 #define RETURN return (dst0) 70 #define VAL c0 71 #define WIDEVAL c 72 73 void * 74 memset(void *dst0, register int c0, register size_t length) 75 76 77 78 #endif 79 { 80 register size_t t; 81 register u_int c; 82 register u_char *dst; 83 84 dst = dst0; 85 /* 86 * If not enough words, just fill bytes. A length >= 2 words 87 * guarantees that at least one of them is `complete' after 88 * any necessary alignment. For instance: 89 * 90 * |-----------|-----------|-----------| 91 * |00|01|02|03|04|05|06|07|08|09|0A|00| 92 * ^---------------------^ 93 * dst dst+length-1 94 * 95 * but we use a minimum of 3 here since the overhead of the code 96 * to do word writes is substantial. 97 */ 98 if (length < 3 * wsize) { 99 while (length != 0) { 100 *dst++ = VAL; 101 --length; 102 } 103 RETURN; 104 } 105 106 #ifndef BZERO 107 if ((c = (u_char)c0) != 0) { /* Fill the word. */ 108 c = (c << 8) | c; /* u_int is 16 bits. */ 109 #if UINT_MAX > 0xffff 110 c = (c << 16) | c; /* u_int is 32 bits. */ 111 #endif 112 #if UINT_MAX > 0xffffffff 113 c = (c << 32) | c; /* u_int is 64 bits. */ 114 #endif 115 } 116 #endif 117 /* Align destination by filling in bytes. */ 118 if ((t = (int)dst & wmask) != 0) { 119 t = wsize - t; 120 length -= t; 121 do { 122 *dst++ = VAL; 123 } while (--t != 0); 124 } 125 126 /* Fill words. Length was >= 2*words so we know t >= 1 here. */ 127 t = length / wsize; 128 do { 129 *(u_int *)dst = WIDEVAL; 130 dst += wsize; 131 } while (--t != 0); 132 133 /* Mop up trailing bytes, if any. */ 134 t = length & wmask; 135 if (t != 0) 136 do { 137 *dst++ = VAL; 138 } while (--t != 0); 139 RETURN; 140 } 141