arch/openrisc/lib/memcpy.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * arch/openrisc/lib/memcpy.c
   4  *
   5  * Optimized memory copy routines for openrisc.  These are mostly copied
   6  * from ohter sources but slightly entended based on ideas discuassed in
   7  * #openrisc.
   8  *
   9  * The word unroll implementation is an extension to the arm byte
  10  * unrolled implementation, but using word copies (if things are
  11  * properly aligned)
  12  *
  13  * The great arm loop unroll algorithm can be found at:
  14  *  arch/arm/boot/compressed/string.c
  15  */
  16
  17 #include <linux/export.h>
  18
  19 #include <linux/string.h>
  20
  21 #ifdef CONFIG_OR1K_1200
  22 /*
  23  * Do memcpy with word copies and loop unrolling. This gives the
  24  * best performance on the OR1200 and MOR1KX archirectures
  25  */
  26 void *memcpy(void *dest, __const void *src, __kernel_size_t n)
  27 {
  28         int i = 0;
  29         unsigned char *d, *s;
  30         uint32_t *dest_w = (uint32_t *)dest, *src_w = (uint32_t *)src;
  31
  32         /* If both source and dest are word aligned copy words */
  33         if (!((unsigned int)dest_w & 3) && !((unsigned int)src_w & 3)) {
  34                 /* Copy 32 bytes per loop */
  35                 for (i = n >> 5; i > 0; i--) {
  36                         *dest_w++ = *src_w++;
  37                         *dest_w++ = *src_w++;
  38                         *dest_w++ = *src_w++;
  39                         *dest_w++ = *src_w++;
  40                         *dest_w++ = *src_w++;
  41                         *dest_w++ = *src_w++;
  42                         *dest_w++ = *src_w++;
  43                         *dest_w++ = *src_w++;
  44                 }
  45
  46                 if (n & 1 << 4) {
  47                         *dest_w++ = *src_w++;
  48                         *dest_w++ = *src_w++;
  49                         *dest_w++ = *src_w++;
  50                         *dest_w++ = *src_w++;
  51                 }
  52
  53                 if (n & 1 << 3) {
  54                         *dest_w++ = *src_w++;
  55                         *dest_w++ = *src_w++;
  56                 }
  57
  58                 if (n & 1 << 2)
  59                         *dest_w++ = *src_w++;
  60
  61                 d = (unsigned char *)dest_w;
  62                 s = (unsigned char *)src_w;
  63
  64         } else {
  65                 d = (unsigned char *)dest_w;
  66                 s = (unsigned char *)src_w;
  67
  68                 for (i = n >> 3; i > 0; i--) {
  69                         *d++ = *s++;
  70                         *d++ = *s++;
  71                         *d++ = *s++;
  72                         *d++ = *s++;
  73                         *d++ = *s++;
  74                         *d++ = *s++;
  75                         *d++ = *s++;
  76                         *d++ = *s++;
  77                 }
  78
  79                 if (n & 1 << 2) {
  80                         *d++ = *s++;
  81                         *d++ = *s++;
  82                         *d++ = *s++;
  83                         *d++ = *s++;
  84                 }
  85         }
  86
  87         if (n & 1 << 1) {
  88                 *d++ = *s++;
  89                 *d++ = *s++;
  90         }
  91
  92         if (n & 1)
  93                 *d++ = *s++;
  94
  95         return dest;
  96 }
  97 #else
  98 /*
  99  * Use word copies but no loop unrolling as we cannot assume there
 100  * will be benefits on the archirecture
 101  */
 102 void *memcpy(void *dest, __const void *src, __kernel_size_t n)
 103 {
 104         unsigned char *d = (unsigned char *)dest, *s = (unsigned char *)src;
 105         uint32_t *dest_w = (uint32_t *)dest, *src_w = (uint32_t *)src;
 106
 107         /* If both source and dest are word aligned copy words */
 108         if (!((unsigned int)dest_w & 3) && !((unsigned int)src_w & 3)) {
 109                 for (; n >= 4; n -= 4)
 110                         *dest_w++ = *src_w++;
 111         }
 112
 113         d = (unsigned char *)dest_w;
 114         s = (unsigned char *)src_w;
 115
 116         /* For remaining or if not aligned, copy bytes */
 117         for (; n >= 1; n -= 1)
 118                 *d++ = *s++;
 119
 120         return dest;
 121
 122 }
 123 #endif
 124
 125 EXPORT_SYMBOL(memcpy);