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125 lines
2.6 KiB
125 lines
2.6 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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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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