arch/nios2/lib/memmove.c

   1 /*
   2  * Copyright (C) 2011 Tobias Klauser <[email protected]>
   3  * Copyright (C) 2004 Microtronix Datacom Ltd
   4  *
   5  * This file is subject to the terms and conditions of the GNU General Public
   6  * License.  See the file "COPYING" in the main directory of this archive
   7  * for more details.
   8  */
   9
  10 #include <linux/types.h>
  11 #include <linux/string.h>
  12
  13 void *memmove(void *d, const void *s, size_t count)
  14 {
  15         unsigned long dst, src;
  16
  17         if (!count)
  18                 return d;
  19
  20         if (d < s) {
  21                 dst = (unsigned long) d;
  22                 src = (unsigned long) s;
  23
  24                 if ((count < 8) || ((dst ^ src) & 3))
  25                         goto restup;
  26
  27                 if (dst & 1) {
  28                         *(char *)dst++ = *(char *)src++;
  29                         count--;
  30                 }
  31                 if (dst & 2) {
  32                         *(short *)dst = *(short *)src;
  33                         src += 2;
  34                         dst += 2;
  35                         count -= 2;
  36                 }
  37                 while (count > 3) {
  38                         *(long *)dst = *(long *)src;
  39                         src += 4;
  40                         dst += 4;
  41                         count -= 4;
  42                 }
  43 restup:
  44                 while (count--)
  45                         *(char *)dst++ = *(char *)src++;
  46         } else {
  47                 dst = (unsigned long) d + count;
  48                 src = (unsigned long) s + count;
  49
  50                 if ((count < 8) || ((dst ^ src) & 3))
  51                         goto restdown;
  52
  53                 if (dst & 1) {
  54                         src--;
  55                         dst--;
  56                         count--;
  57                         *(char *)dst = *(char *)src;
  58                 }
  59                 if (dst & 2) {
  60                         src -= 2;
  61                         dst -= 2;
  62                         count -= 2;
  63                         *(short *)dst = *(short *)src;
  64                 }
  65                 while (count > 3) {
  66                         src -= 4;
  67                         dst -= 4;
  68                         count -= 4;
  69                         *(long *)dst = *(long *)src;
  70                 }
  71 restdown:
  72                 while (count--) {
  73                         src--;
  74                         dst--;
  75                         *(char *)dst = *(char *)src;
  76                 }
  77         }
  78
  79         return d;
  80 }