125 строки
2.6 KiB
C
125 строки
2.6 KiB
C
/*
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* arch/openrisc/lib/memcpy.c
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*
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* Optimized memory copy routines for openrisc. These are mostly copied
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* from ohter sources but slightly entended based on ideas discuassed in
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* #openrisc.
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*
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* The word unroll implementation is an extension to the arm byte
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* unrolled implementation, but using word copies (if things are
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* properly aligned)
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*
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* The great arm loop unroll algorithm can be found at:
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* arch/arm/boot/compressed/string.c
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*/
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#include <linux/export.h>
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#include <linux/string.h>
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#ifdef CONFIG_OR1K_1200
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/*
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* Do memcpy with word copies and loop unrolling. This gives the
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* best performance on the OR1200 and MOR1KX archirectures
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*/
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void *memcpy(void *dest, __const void *src, __kernel_size_t n)
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{
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int i = 0;
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unsigned char *d, *s;
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uint32_t *dest_w = (uint32_t *)dest, *src_w = (uint32_t *)src;
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/* If both source and dest are word aligned copy words */
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if (!((unsigned int)dest_w & 3) && !((unsigned int)src_w & 3)) {
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/* Copy 32 bytes per loop */
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for (i = n >> 5; i > 0; i--) {
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*dest_w++ = *src_w++;
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*dest_w++ = *src_w++;
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*dest_w++ = *src_w++;
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*dest_w++ = *src_w++;
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*dest_w++ = *src_w++;
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*dest_w++ = *src_w++;
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*dest_w++ = *src_w++;
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*dest_w++ = *src_w++;
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}
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if (n & 1 << 4) {
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*dest_w++ = *src_w++;
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*dest_w++ = *src_w++;
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*dest_w++ = *src_w++;
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*dest_w++ = *src_w++;
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}
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if (n & 1 << 3) {
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*dest_w++ = *src_w++;
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*dest_w++ = *src_w++;
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}
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if (n & 1 << 2)
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*dest_w++ = *src_w++;
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d = (unsigned char *)dest_w;
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s = (unsigned char *)src_w;
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} else {
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d = (unsigned char *)dest_w;
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s = (unsigned char *)src_w;
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for (i = n >> 3; i > 0; i--) {
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*d++ = *s++;
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*d++ = *s++;
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*d++ = *s++;
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*d++ = *s++;
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*d++ = *s++;
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*d++ = *s++;
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*d++ = *s++;
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*d++ = *s++;
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}
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if (n & 1 << 2) {
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*d++ = *s++;
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*d++ = *s++;
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*d++ = *s++;
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*d++ = *s++;
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}
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}
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if (n & 1 << 1) {
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*d++ = *s++;
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*d++ = *s++;
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}
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if (n & 1)
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*d++ = *s++;
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return dest;
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}
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#else
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/*
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* Use word copies but no loop unrolling as we cannot assume there
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* will be benefits on the archirecture
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*/
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void *memcpy(void *dest, __const void *src, __kernel_size_t n)
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{
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unsigned char *d = (unsigned char *)dest, *s = (unsigned char *)src;
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uint32_t *dest_w = (uint32_t *)dest, *src_w = (uint32_t *)src;
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/* If both source and dest are word aligned copy words */
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if (!((unsigned int)dest_w & 3) && !((unsigned int)src_w & 3)) {
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for (; n >= 4; n -= 4)
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*dest_w++ = *src_w++;
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}
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d = (unsigned char *)dest_w;
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s = (unsigned char *)src_w;
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/* For remaining or if not aligned, copy bytes */
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for (; n >= 1; n -= 1)
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*d++ = *s++;
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return dest;
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}
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#endif
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EXPORT_SYMBOL(memcpy);
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