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63 lines
1.4 KiB
63 lines
1.4 KiB
/* |
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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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