arch/nios2/lib/memmove.c

   1 /*
   2  * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
   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 #ifdef __HAVE_ARCH_MEMMOVE
  14 void *memmove(void *d, const void *s, size_t count)
  15 {
  16         unsigned long dst, src;
  17
  18         if (!count)
  19                 return d;
  20
  21         if (d < s) {
  22                 dst = (unsigned long) d;
  23                 src = (unsigned long) s;
  24
  25                 if ((count < 8) || ((dst ^ src) & 3))
  26                         goto restup;
  27
  28                 if (dst & 1) {
  29                         *(char *)dst++ = *(char *)src++;
  30                         count--;
  31                 }
  32                 if (dst & 2) {
  33                         *(short *)dst = *(short *)src;
  34                         src += 2;
  35                         dst += 2;
  36                         count -= 2;
  37                 }
  38                 while (count > 3) {
  39                         *(long *)dst = *(long *)src;
  40                         src += 4;
  41                         dst += 4;
  42                         count -= 4;
  43                 }
  44 restup:
  45                 while (count--)
  46                         *(char *)dst++ = *(char *)src++;
  47         } else {
  48                 dst = (unsigned long) d + count;
  49                 src = (unsigned long) s + count;
  50
  51                 if ((count < 8) || ((dst ^ src) & 3))
  52                         goto restdown;
  53
  54                 if (dst & 1) {
  55                         src--;
  56                         dst--;
  57                         count--;
  58                         *(char *)dst = *(char *)src;
  59                 }
  60                 if (dst & 2) {
  61                         src -= 2;
  62                         dst -= 2;
  63                         count -= 2;
  64                         *(short *)dst = *(short *)src;
  65                 }
  66                 while (count > 3) {
  67                         src -= 4;
  68                         dst -= 4;
  69                         count -= 4;
  70                         *(long *)dst = *(long *)src;
  71                 }
  72 restdown:
  73                 while (count--) {
  74                         src--;
  75                         dst--;
  76                         *(char *)dst = *(char *)src;
  77                 }
  78         }
  79
  80         return d;
  81 }
  82 #endif /* __HAVE_ARCH_MEMMOVE */