64 lines
1.4 KiB
C
64 lines
1.4 KiB
C
/*
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* Copyright 2010 Tilera Corporation. All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for
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* more details.
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*/
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#include <linux/types.h>
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#include <linux/string.h>
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#include <linux/module.h>
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void *memmove(void *dest, const void *src, size_t n)
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{
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if ((const char *)src >= (char *)dest + n
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|| (char *)dest >= (const char *)src + n) {
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/* We found no overlap, so let memcpy do all the heavy
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* lifting (prefetching, etc.)
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*/
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return memcpy(dest, src, n);
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}
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if (n != 0) {
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const uint8_t *in;
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uint8_t x;
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uint8_t *out;
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int stride;
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if (src < dest) {
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/* copy backwards */
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in = (const uint8_t *)src + n - 1;
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out = (uint8_t *)dest + n - 1;
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stride = -1;
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} else {
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/* copy forwards */
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in = (const uint8_t *)src;
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out = (uint8_t *)dest;
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stride = 1;
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}
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/* Manually software-pipeline this loop. */
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x = *in;
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in += stride;
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while (--n != 0) {
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*out = x;
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out += stride;
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x = *in;
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in += stride;
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}
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*out = x;
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}
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return dest;
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}
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EXPORT_SYMBOL(memmove);
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