arch/sh/lib64/memcpy.c

   1 /*
   2  * Copyright (C) 2002 Mark Debbage (Mark.Debbage@superh.com)
   3  *
   4  * May be copied or modified under the terms of the GNU General Public
   5  * License.  See linux/COPYING for more information.
   6  *
   7  */
   8
   9 #include <linux/types.h>
  10 #include <asm/string.h>
  11
  12 // This is a simplistic optimization of memcpy to increase the
  13 // granularity of access beyond one byte using aligned
  14 // loads and stores. This is not an optimal implementation
  15 // for SH-5 (especially with regard to prefetching and the cache),
  16 // and a better version should be provided later ...
  17
  18 void *memcpy(void *dest, const void *src, size_t count)
  19 {
  20         char *d = (char *) dest, *s = (char *) src;
  21
  22         if (count >= 32) {
  23                 int i = 8 - (((unsigned long) d) & 0x7);
  24
  25                 if (i != 8)
  26                         while (i-- && count--) {
  27                                 *d++ = *s++;
  28                         }
  29
  30                 if (((((unsigned long) d) & 0x7) == 0) &&
  31                     ((((unsigned long) s) & 0x7) == 0)) {
  32                         while (count >= 32) {
  33                                 unsigned long long t1, t2, t3, t4;
  34                                 t1 = *(unsigned long long *) (s);
  35                                 t2 = *(unsigned long long *) (s + 8);
  36                                 t3 = *(unsigned long long *) (s + 16);
  37                                 t4 = *(unsigned long long *) (s + 24);
  38                                 *(unsigned long long *) (d) = t1;
  39                                 *(unsigned long long *) (d + 8) = t2;
  40                                 *(unsigned long long *) (d + 16) = t3;
  41                                 *(unsigned long long *) (d + 24) = t4;
  42                                 d += 32;
  43                                 s += 32;
  44                                 count -= 32;
  45                         }
  46                         while (count >= 8) {
  47                                 *(unsigned long long *) d =
  48                                     *(unsigned long long *) s;
  49                                 d += 8;
  50                                 s += 8;
  51                                 count -= 8;
  52                         }
  53                 }
  54
  55                 if (((((unsigned long) d) & 0x3) == 0) &&
  56                     ((((unsigned long) s) & 0x3) == 0)) {
  57                         while (count >= 4) {
  58                                 *(unsigned long *) d = *(unsigned long *) s;
  59                                 d += 4;
  60                                 s += 4;
  61                                 count -= 4;
  62                         }
  63                 }
  64
  65                 if (((((unsigned long) d) & 0x1) == 0) &&
  66                     ((((unsigned long) s) & 0x1) == 0)) {
  67                         while (count >= 2) {
  68                                 *(unsigned short *) d = *(unsigned short *) s;
  69                                 d += 2;
  70                                 s += 2;
  71                                 count -= 2;
  72                         }
  73                 }
  74         }
  75
  76         while (count--) {
  77                 *d++ = *s++;
  78         }
  79
  80         return d;
  81 }