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 #if defined(LIBC_SCCS) && !defined(lint) 38 static char sccsid[] = "@(#)memset.c 8.1 (Berkeley) 6/4/93"; 39 #endif /* LIBC_SCCS and not lint */ 40 #include <sys/cdefs.h> 41 __FBSDID("$FreeBSD$"); 42 43 #include <sys/types.h> 44 45 #include <limits.h> 46 #include <string.h> 47 48 #define wsize sizeof(u_int) 49 #define wmask (wsize - 1) 50 51 #ifdef BZERO 52 #define RETURN return 53 #define VAL 0 54 #define WIDEVAL 0 55 56 void 57 bzero(dst0, length) 58 void *dst0; 59 size_t length; 60 #else 61 #define RETURN return (dst0) 62 #define VAL c0 63 #define WIDEVAL c 64 65 void * 66 memset(dst0, c0, length) 67 void *dst0; 68 int c0; 69 size_t length; 70 #endif 71 { 72 size_t t; 73 #ifndef BZERO 74 u_int c; 75 #endif 76 u_char *dst; 77 78 dst = dst0; 79 /* 80 * If not enough words, just fill bytes. A length >= 2 words 81 * guarantees that at least one of them is `complete' after 82 * any necessary alignment. For instance: 83 * 84 * |-----------|-----------|-----------| 85 * |00|01|02|03|04|05|06|07|08|09|0A|00| 86 * ^---------------------^ 87 * dst dst+length-1 88 * 89 * but we use a minimum of 3 here since the overhead of the code 90 * to do word writes is substantial. 91 */ 92 if (length < 3 * wsize) { 93 while (length != 0) { 94 *dst++ = VAL; 95 --length; 96 } 97 RETURN; 98 } 99 100 #ifndef BZERO 101 if ((c = (u_char)c0) != 0) { /* Fill the word. */ 102 c = (c << 8) | c; /* u_int is 16 bits. */ 103 #if UINT_MAX > 0xffff 104 c = (c << 16) | c; /* u_int is 32 bits. */ 105 #endif 106 #if UINT_MAX > 0xffffffff 107 c = (c << 32) | c; /* u_int is 64 bits. */ 108 #endif 109 } 110 #endif 111 /* Align destination by filling in bytes. */ 112 if ((t = (long)dst & wmask) != 0) { 113 t = wsize - t; 114 length -= t; 115 do { 116 *dst++ = VAL; 117 } while (--t != 0); 118 } 119 120 /* Fill words. Length was >= 2*words so we know t >= 1 here. */ 121 t = length / wsize; 122 do { 123 *(u_int *)dst = WIDEVAL; 124 dst += wsize; 125 } while (--t != 0); 126 127 /* Mop up trailing bytes, if any. */ 128 t = length & wmask; 129 if (t != 0) 130 do { 131 *dst++ = VAL; 132 } while (--t != 0); 133 RETURN; 134 } 135