arch/sh64/lib/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/config.h>
  10 #include <linux/types.h>
  11 #include <asm/string.h>
  12
  13 // This is a simplistic optimization of memcpy to increase the
  14 // granularity of access beyond one byte using aligned
  15 // loads and stores. This is not an optimal implementation
  16 // for SH-5 (especially with regard to prefetching and the cache),
  17 // and a better version should be provided later ...
  18
  19 void *memcpy(void *dest, const void *src, size_t count)
  20 {
  21         char *d = (char *) dest, *s = (char *) src;
  22
  23         if (count >= 32) {
  24                 int i = 8 - (((unsigned long) d) & 0x7);
  25
  26                 if (i != 8)
  27                         while (i-- && count--) {
  28                                 *d++ = *s++;
  29                         }
  30
  31                 if (((((unsigned long) d) & 0x7) == 0) &&
  32                     ((((unsigned long) s) & 0x7) == 0)) {
  33                         while (count >= 32) {
  34                                 unsigned long long t1, t2, t3, t4;
  35                                 t1 = *(unsigned long long *) (s);
  36                                 t2 = *(unsigned long long *) (s + 8);
  37                                 t3 = *(unsigned long long *) (s + 16);
  38                                 t4 = *(unsigned long long *) (s + 24);
  39                                 *(unsigned long long *) (d) = t1;
  40                                 *(unsigned long long *) (d + 8) = t2;
  41                                 *(unsigned long long *) (d + 16) = t3;
  42                                 *(unsigned long long *) (d + 24) = t4;
  43                                 d += 32;
  44                                 s += 32;
  45                                 count -= 32;
  46                         }
  47                         while (count >= 8) {
  48                                 *(unsigned long long *) d =
  49                                     *(unsigned long long *) s;
  50                                 d += 8;
  51                                 s += 8;
  52                                 count -= 8;
  53                         }
  54                 }
  55
  56                 if (((((unsigned long) d) & 0x3) == 0) &&
  57                     ((((unsigned long) s) & 0x3) == 0)) {
  58                         while (count >= 4) {
  59                                 *(unsigned long *) d = *(unsigned long *) s;
  60                                 d += 4;
  61                                 s += 4;
  62                                 count -= 4;
  63                         }
  64                 }
  65
  66                 if (((((unsigned long) d) & 0x1) == 0) &&
  67                     ((((unsigned long) s) & 0x1) == 0)) {
  68                         while (count >= 2) {
  69                                 *(unsigned short *) d = *(unsigned short *) s;
  70                                 d += 2;
  71                                 s += 2;
  72                                 count -= 2;
  73                         }
  74                 }
  75         }
  76
  77         while (count--) {
  78                 *d++ = *s++;
  79         }
  80
  81         return d;
  82 }