95 строки
2.2 KiB
C
95 строки
2.2 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 memset 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/export.h>
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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/string.h>
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#ifdef CONFIG_OPT_LIB_FUNCTION
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void *memset(void *v_src, int c, __kernel_size_t n)
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{
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char *src = v_src;
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uint32_t *i_src;
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uint32_t w32 = 0;
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/* Truncate c to 8 bits */
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c = (c & 0xFF);
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if (unlikely(c)) {
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/* Make a repeating word out of it */
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w32 = c;
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w32 |= w32 << 8;
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w32 |= w32 << 16;
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}
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if (likely(n >= 4)) {
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/* Align the destination to a word boundary */
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/* This is done in an endian independent manner */
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switch ((unsigned) src & 3) {
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case 1:
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*src++ = c;
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--n;
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fallthrough;
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case 2:
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*src++ = c;
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--n;
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fallthrough;
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case 3:
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*src++ = c;
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--n;
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}
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i_src = (void *)src;
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/* Do as many full-word copies as we can */
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for (; n >= 4; n -= 4)
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*i_src++ = w32;
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src = (void *)i_src;
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}
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/* Simple, byte oriented memset or the rest of count. */
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switch (n) {
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case 3:
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*src++ = c;
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fallthrough;
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case 2:
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*src++ = c;
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fallthrough;
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case 1:
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*src++ = c;
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break;
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default:
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break;
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}
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return v_src;
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}
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EXPORT_SYMBOL(memset);
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#endif /* CONFIG_OPT_LIB_FUNCTION */
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