src/system/libroot/posix/string/arch/generic/memcpy.c

   1 /*
   2 ** Copyright 2001, Travis Geiselbrecht. All rights reserved.
   3 ** Distributed under the terms of the NewOS License.
   4 */
   5
   6 #include <sys/types.h>
   7 #include <string.h>
   8
   9 /* do not build for for arches that have overridden this with an assembly version */
  10 #if !defined(ARCH_x86)
  11
  12 typedef int word;
  13
  14 #define lsize sizeof(word)
  15 #define lmask (lsize - 1)
  16
  17 void *memcpy(void *dest, const void *src, size_t count)
  18 {
  19         char *d = (char *)dest;
  20         const char *s = (const char *)src;
  21         int len;
  22
  23         if(count == 0 || dest == src)
  24                 return dest;
  25
  26         if(((long)d | (long)s) & lmask) {
  27                 // src and/or dest do not align on word boundary
  28                 if((((long)d ^ (long)s) & lmask) || (count < lsize))
  29                         len = count; // copy the rest of the buffer with the byte mover
  30                 else
  31                         len = lsize - ((long)d & lmask); // move the ptrs up to a word boundary
  32
  33                 count -= len;
  34                 for(; len > 0; len--)
  35                         *d++ = *s++;
  36         }
  37         for(len = count / lsize; len > 0; len--) {
  38                 *(word *)d = *(word *)s;
  39                 d += lsize;
  40                 s += lsize;
  41         }
  42         for(len = count & lmask; len > 0; len--)
  43                 *d++ = *s++;
  44
  45         return dest;
  46 }
  47
  48 #endif
  49