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1180b28ca8
Optimized C library functions can rapidly speedup the kernel. memset doesn't need to be optimized because there is no difference in behavior on little/big endian cpu. Signed-off-by: Michal Simek <monstr@monstr.eu>
191 lines
4.9 KiB
C
191 lines
4.9 KiB
C
/*
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* Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
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* Copyright (C) 2008-2009 PetaLogix
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* Copyright (C) 2007 John Williams
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*
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* Reasonably optimised generic C-code for memcpy on Microblaze
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* This is generic C code to do efficient, alignment-aware memcpy.
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*
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* It is based on demo code originally Copyright 2001 by Intel Corp, taken from
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* http://www.embedded.com/showArticle.jhtml?articleID=19205567
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*
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* Attempts were made, unsuccessfully, to contact the original
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* author of this code (Michael Morrow, Intel). Below is the original
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* copyright notice.
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*
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* This software has been developed by Intel Corporation.
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* Intel specifically disclaims all warranties, express or
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* implied, and all liability, including consequential and
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* other indirect damages, for the use of this program, including
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* liability for infringement of any proprietary rights,
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* and including the warranties of merchantability and fitness
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* for a particular purpose. Intel does not assume any
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* responsibility for and errors which may appear in this program
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* not any responsibility to update it.
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*/
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#include <linux/types.h>
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#include <linux/stddef.h>
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#include <linux/compiler.h>
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#include <linux/module.h>
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#include <linux/string.h>
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#include <asm/system.h>
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#ifdef __HAVE_ARCH_MEMCPY
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#ifndef CONFIG_OPT_LIB_FUNCTION
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void *memcpy(void *v_dst, const void *v_src, __kernel_size_t c)
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{
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const char *src = v_src;
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char *dst = v_dst;
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/* Simple, byte oriented memcpy. */
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while (c--)
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*dst++ = *src++;
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return v_dst;
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}
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#else /* CONFIG_OPT_LIB_FUNCTION */
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void *memcpy(void *v_dst, const void *v_src, __kernel_size_t c)
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{
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const char *src = v_src;
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char *dst = v_dst;
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/* The following code tries to optimize the copy by using unsigned
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* alignment. This will work fine if both source and destination are
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* aligned on the same boundary. However, if they are aligned on
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* different boundaries shifts will be necessary. This might result in
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* bad performance on MicroBlaze systems without a barrel shifter.
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*/
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const uint32_t *i_src;
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uint32_t *i_dst;
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if (likely(c >= 4)) {
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unsigned value, buf_hold;
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/* Align the dstination to a word boundry. */
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/* This is done in an endian independant manner. */
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switch ((unsigned long)dst & 3) {
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case 1:
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*dst++ = *src++;
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--c;
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case 2:
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*dst++ = *src++;
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--c;
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case 3:
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*dst++ = *src++;
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--c;
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}
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i_dst = (void *)dst;
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/* Choose a copy scheme based on the source */
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/* alignment relative to dstination. */
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switch ((unsigned long)src & 3) {
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case 0x0: /* Both byte offsets are aligned */
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i_src = (const void *)src;
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for (; c >= 4; c -= 4)
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*i_dst++ = *i_src++;
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src = (const void *)i_src;
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break;
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case 0x1: /* Unaligned - Off by 1 */
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/* Word align the source */
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i_src = (const void *) ((unsigned)src & ~3);
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#ifndef __MICROBLAZEEL__
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/* Load the holding buffer */
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buf_hold = *i_src++ << 8;
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for (; c >= 4; c -= 4) {
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value = *i_src++;
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*i_dst++ = buf_hold | value >> 24;
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buf_hold = value << 8;
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}
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#else
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/* Load the holding buffer */
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buf_hold = (*i_src++ & 0xFFFFFF00) >>8;
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for (; c >= 4; c -= 4) {
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value = *i_src++;
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*i_dst++ = buf_hold | ((value & 0xFF) << 24);
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buf_hold = (value & 0xFFFFFF00) >>8;
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}
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#endif
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/* Realign the source */
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src = (const void *)i_src;
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src -= 3;
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break;
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case 0x2: /* Unaligned - Off by 2 */
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/* Word align the source */
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i_src = (const void *) ((unsigned)src & ~3);
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#ifndef __MICROBLAZEEL__
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/* Load the holding buffer */
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buf_hold = *i_src++ << 16;
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for (; c >= 4; c -= 4) {
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value = *i_src++;
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*i_dst++ = buf_hold | value >> 16;
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buf_hold = value << 16;
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}
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#else
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/* Load the holding buffer */
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buf_hold = (*i_src++ & 0xFFFF0000 )>>16;
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for (; c >= 4; c -= 4) {
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value = *i_src++;
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*i_dst++ = buf_hold | ((value & 0xFFFF)<<16);
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buf_hold = (value & 0xFFFF0000) >>16;
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}
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#endif
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/* Realign the source */
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src = (const void *)i_src;
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src -= 2;
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break;
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case 0x3: /* Unaligned - Off by 3 */
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/* Word align the source */
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i_src = (const void *) ((unsigned)src & ~3);
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#ifndef __MICROBLAZEEL__
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/* Load the holding buffer */
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buf_hold = *i_src++ << 24;
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for (; c >= 4; c -= 4) {
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value = *i_src++;
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*i_dst++ = buf_hold | value >> 8;
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buf_hold = value << 24;
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}
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#else
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/* Load the holding buffer */
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buf_hold = (*i_src++ & 0xFF000000) >> 24;
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for (; c >= 4; c -= 4) {
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value = *i_src++;
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*i_dst++ = buf_hold | ((value & 0xFFFFFF) << 8);
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buf_hold = (value & 0xFF000000) >> 24;
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}
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#endif
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/* Realign the source */
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src = (const void *)i_src;
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src -= 1;
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break;
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}
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dst = (void *)i_dst;
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}
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/* Finish off any remaining bytes */
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/* simple fast copy, ... unless a cache boundry is crossed */
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switch (c) {
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case 3:
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*dst++ = *src++;
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case 2:
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*dst++ = *src++;
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case 1:
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*dst++ = *src++;
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}
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return v_dst;
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}
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#endif /* CONFIG_OPT_LIB_FUNCTION */
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EXPORT_SYMBOL(memcpy);
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#endif /* __HAVE_ARCH_MEMCPY */
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