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. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <sys/cdefs.h> 34 __FBSDID("$FreeBSD$"); 35 36 #include <sys/types.h> 37 38 #include <limits.h> 39 40 #define wsize sizeof(u_int) 41 #define wmask (wsize - 1) 42 43 #ifdef BZERO 44 #include <strings.h> 45 46 #define RETURN return 47 #define VAL 0 48 #define WIDEVAL 0 49 50 void 51 bzero(void *dst0, size_t length) 52 #else 53 #include <string.h> 54 55 #define RETURN return (dst0) 56 #define VAL c0 57 #define WIDEVAL c 58 59 void * 60 memset(void *dst0, int c0, size_t length) 61 #endif 62 { 63 size_t t; 64 #ifndef BZERO 65 u_int c; 66 #endif 67 u_char *dst; 68 69 dst = dst0; 70 /* 71 * If not enough words, just fill bytes. A length >= 2 words 72 * guarantees that at least one of them is `complete' after 73 * any necessary alignment. For instance: 74 * 75 * |-----------|-----------|-----------| 76 * |00|01|02|03|04|05|06|07|08|09|0A|00| 77 * ^---------------------^ 78 * dst dst+length-1 79 * 80 * but we use a minimum of 3 here since the overhead of the code 81 * to do word writes is substantial. 82 */ 83 if (length < 3 * wsize) { 84 while (length != 0) { 85 *dst++ = VAL; 86 --length; 87 } 88 RETURN; 89 } 90 91 #ifndef BZERO 92 if ((c = (u_char)c0) != 0) { /* Fill the word. */ 93 c = (c << 8) | c; /* u_int is 16 bits. */ 94 #if UINT_MAX > 0xffff 95 c = (c << 16) | c; /* u_int is 32 bits. */ 96 #endif 97 #if UINT_MAX > 0xffffffff 98 c = (c << 32) | c; /* u_int is 64 bits. */ 99 #endif 100 } 101 #endif 102 /* Align destination by filling in bytes. */ 103 if ((t = (long)dst & wmask) != 0) { 104 t = wsize - t; 105 length -= t; 106 do { 107 *dst++ = VAL; 108 } while (--t != 0); 109 } 110 111 /* Fill words. Length was >= 2*words so we know t >= 1 here. */ 112 t = length / wsize; 113 do { 114 *(u_int *)dst = WIDEVAL; 115 dst += wsize; 116 } while (--t != 0); 117 118 /* Mop up trailing bytes, if any. */ 119 t = length & wmask; 120 if (t != 0) 121 do { 122 *dst++ = VAL; 123 } while (--t != 0); 124 RETURN; 125 } 126
