dbm/src/memmove.c

   1 #if defined(__sun) && !defined(__SVR4)
   2 /*-
   3  * Copyright (c) 1990, 1993
   4  *      The Regents of the University of California.  All rights reserved.
   5  *
   6  * This code is derived from software contributed to Berkeley by
   7  * Chris Torek.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. ***REMOVED*** - see
  18  *    ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change
  19  * 4. Neither the name of the University nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #if defined(LIBC_SCCS) && !defined(lint)
  37 static char sccsid[] = "@(#)bcopy.c     8.1 (Berkeley) 6/4/93";
  38 #endif /* LIBC_SCCS and not lint */
  39
  40 #include "watcomfx.h"
  41
  42 #ifdef HAVE_SYS_CDEFS_H
  43 #include <sys/cdefs.h>
  44 #else
  45 #include "cdefs.h"
  46 #endif
  47 #include <string.h>
  48
  49 /*
  50  * sizeof(word) MUST BE A POWER OF TWO
  51  * SO THAT wmask BELOW IS ALL ONES
  52  */
  53 typedef int word;               /* "word" used for optimal copy speed */
  54
  55 #define wsize   sizeof(word)
  56 #define wmask   (wsize - 1)
  57
  58 /*
  59  * Copy a block of memory, handling overlap.
  60  * This is the routine that actually implements
  61  * (the portable versions of) bcopy, memcpy, and memmove.
  62  */
  63 #ifdef MEMCOPY
  64 void *
  65 memcpy(dst0, src0, length)
  66 #else
  67 #ifdef MEMMOVE
  68 void *
  69 memmove(dst0, src0, length)
  70 #else
  71 void
  72 bcopy(src0, dst0, length)
  73 #endif
  74 #endif
  75         void *dst0;
  76         const void *src0;
  77         register size_t length;
  78 {
  79         register char *dst = dst0;
  80         register const char *src = src0;
  81         register size_t t;
  82
  83         if (length == 0 || dst == src)          /* nothing to do */
  84                 goto done;
  85
  86         /*
  87          * Macros: loop-t-times; and loop-t-times, t>0
  88          */
  89 #define TLOOP(s) if (t) TLOOP1(s)
  90 #define TLOOP1(s) do { s; } while (--t)
  91
  92         if ((unsigned long)dst < (unsigned long)src) {
  93                 /*
  94                  * Copy forward.
  95                  */
  96                 t = (int)src;   /* only need low bits */
  97                 if ((t | (int)dst) & wmask) {
  98                         /*
  99                          * Try to align operands.  This cannot be done
 100                          * unless the low bits match.
 101                          */
 102                         if ((t ^ (int)dst) & wmask || length < wsize)
 103                                 t = length;
 104                         else
 105                                 t = wsize - (t & wmask);
 106                         length -= t;
 107                         TLOOP1(*dst++ = *src++);
 108                 }
 109                 /*
 110                  * Copy whole words, then mop up any trailing bytes.
 111                  */
 112                 t = length / wsize;
 113                 TLOOP(*(word *)dst = *(word *)src; src += wsize; dst += wsize);
 114                 t = length & wmask;
 115                 TLOOP(*dst++ = *src++);
 116         } else {
 117                 /*
 118                  * Copy backwards.  Otherwise essentially the same.
 119                  * Alignment works as before, except that it takes
 120                  * (t&wmask) bytes to align, not wsize-(t&wmask).
 121                  */
 122                 src += length;
 123                 dst += length;
 124                 t = (int)src;
 125                 if ((t | (int)dst) & wmask) {
 126                         if ((t ^ (int)dst) & wmask || length <= wsize)
 127                                 t = length;
 128                         else
 129                                 t &= wmask;
 130                         length -= t;
 131                         TLOOP1(*--dst = *--src);
 132                 }
 133                 t = length / wsize;
 134                 TLOOP(src -= wsize; dst -= wsize; *(word *)dst = *(word *)src);
 135                 t = length & wmask;
 136                 TLOOP(*--dst = *--src);
 137         }
 138 done:
 139 #if defined(MEMCOPY) || defined(MEMMOVE)
 140         return (dst0);
 141 #else
 142         return;
 143 #endif
 144 }
 145 #endif /* no __sgi */
 146
 147 /* Some compilers don't like an empty source file. */
 148 static int dummy = 0;