00001 /* 00002 * Copyright (C) 2004 by egnite Software GmbH. All rights reserved. 00003 * 00004 * Redistribution and use in source and binary forms, with or without 00005 * modification, are permitted provided that the following conditions 00006 * are met: 00007 * 00008 * 1. Redistributions of source code must retain the above copyright 00009 * notice, this list of conditions and the following disclaimer. 00010 * 2. Redistributions in binary form must reproduce the above copyright 00011 * notice, this list of conditions and the following disclaimer in the 00012 * documentation and/or other materials provided with the distribution. 00013 * 3. Neither the name of the copyright holders nor the names of 00014 * contributors may be used to endorse or promote products derived 00015 * from this software without specific prior written permission. 00016 * 00017 * THIS SOFTWARE IS PROVIDED BY EGNITE SOFTWARE GMBH AND CONTRIBUTORS 00018 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 00019 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 00020 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL EGNITE 00021 * SOFTWARE GMBH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 00022 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 00023 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 00024 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 00025 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 00026 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 00027 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 00028 * SUCH DAMAGE. 00029 * 00030 * For additional information see http://www.ethernut.de/ 00031 * 00032 *- 00033 * Copyright (c) 1990 The Regents of the University of California. 00034 * All rights reserved. 00035 * 00036 * This code is derived from software contributed to Berkeley by 00037 * Chris Torek. 00038 * 00039 * Redistribution and use in source and binary forms, with or without 00040 * modification, are permitted provided that the following conditions 00041 * are met: 00042 * 1. Redistributions of source code must retain the above copyright 00043 * notice, this list of conditions and the following disclaimer. 00044 * 2. Redistributions in binary form must reproduce the above copyright 00045 * notice, this list of conditions and the following disclaimer in the 00046 * documentation and/or other materials provided with the distribution. 00047 * 3. Neither the name of the University nor the names of its contributors 00048 * may be used to endorse or promote products derived from this software 00049 * without specific prior written permission. 00050 * 00051 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 00052 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 00053 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 00054 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 00055 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 00056 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 00057 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 00058 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 00059 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 00060 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 00061 * SUCH DAMAGE. 00062 */ 00063 00064 00065 /* 00066 * $Log: memcpy.c,v $ 00067 * Revision 1.2 2005/08/02 17:46:47 haraldkipp 00068 * Major API documentation update. 00069 * 00070 * Revision 1.1 2004/09/08 10:23:43 haraldkipp 00071 * Generic C string library added 00072 * 00073 */ 00074 00075 #include <compiler.h> 00076 #include <string.h> 00077 00082 00097 /* 00098 * sizeof(word) MUST BE A POWER OF TWO 00099 * SO THAT wmask BELOW IS ALL ONES 00100 */ 00101 typedef long word; /* "word" used for optimal copy speed */ 00102 00103 #define wsize sizeof(word) 00104 #define wmask (wsize - 1) 00105 00106 /* 00107 * Copy a block of memory, handling overlap. 00108 * This is the routine that actually implements 00109 * (the portable versions of) bcopy, memcpy, and memmove. 00110 */ 00111 void *memcpy(void *dst0, CONST void *src0, size_t length) 00112 { 00113 register char *dst = dst0; 00114 register const char *src = src0; 00115 register size_t t; 00116 00117 if (length == 0 || dst == src) /* nothing to do */ 00118 goto done; 00119 00120 /* 00121 * Macros: loop-t-times; and loop-t-times, t>0 00122 */ 00123 #define TLOOP(s) if (t) TLOOP1(s) 00124 #define TLOOP1(s) do { s; } while (--t) 00125 00126 if ((unsigned long)dst < (unsigned long)src) { 00127 /* 00128 * Copy forward. 00129 */ 00130 t = (long)src; /* only need low bits */ 00131 if ((t | (long)dst) & wmask) { 00132 /* 00133 * Try to align operands. This cannot be done 00134 * unless the low bits match. 00135 */ 00136 if ((t ^ (long)dst) & wmask || length < wsize) 00137 t = length; 00138 else 00139 t = wsize - (t & wmask); 00140 length -= t; 00141 TLOOP1(*dst++ = *src++); 00142 } 00143 /* 00144 * Copy whole words, then mop up any trailing bytes. 00145 */ 00146 t = length / wsize; 00147 TLOOP(*(word *)dst = *(word *)src; src += wsize; dst += wsize); 00148 t = length & wmask; 00149 TLOOP(*dst++ = *src++); 00150 } else { 00151 /* 00152 * Copy backwards. Otherwise essentially the same. 00153 * Alignment works as before, except that it takes 00154 * (t&wmask) bytes to align, not wsize-(t&wmask). 00155 */ 00156 src += length; 00157 dst += length; 00158 t = (long)src; 00159 if ((t | (long)dst) & wmask) { 00160 if ((t ^ (long)dst) & wmask || length <= wsize) 00161 t = length; 00162 else 00163 t &= wmask; 00164 length -= t; 00165 TLOOP1(*--dst = *--src); 00166 } 00167 t = length / wsize; 00168 TLOOP(src -= wsize; dst -= wsize; *(word *)dst = *(word *)src); 00169 t = length & wmask; 00170 TLOOP(*--dst = *--src); 00171 } 00172 done: 00173 return dst0; 00174 } 00175