LXR linux/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 */
  26void *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 */
 102void *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
 125EXPORT_SYMBOL(memcpy);
 126