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memset.c

/*
 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
 * Copyright (C) 2008-2009 PetaLogix
 * Copyright (C) 2007 John Williams
 *
 * Reasonably optimised generic C-code for memset on Microblaze
 * This is generic C code to do efficient, alignment-aware memcpy.
 *
 * It is based on demo code originally Copyright 2001 by Intel Corp, taken from
 * http://www.embedded.com/showArticle.jhtml?articleID=19205567
 *
 * Attempts were made, unsuccesfully, to contact the original
 * author of this code (Michael Morrow, Intel).  Below is the original
 * copyright notice.
 *
 * This software has been developed by Intel Corporation.
 * Intel specifically disclaims all warranties, express or
 * implied, and all liability, including consequential and
 * other indirect damages, for the use of this program, including
 * liability for infringement of any proprietary rights,
 * and including the warranties of merchantability and fitness
 * for a particular purpose. Intel does not assume any
 * responsibility for and errors which may appear in this program
 * not any responsibility to update it.
 */

#include <linux/types.h>
#include <linux/stddef.h>
#include <linux/compiler.h>
#include <linux/module.h>
#include <linux/string.h>

#ifdef __HAVE_ARCH_MEMSET
void *memset(void *v_src, int c, __kernel_size_t n)
{

      char *src = v_src;
#ifdef CONFIG_OPT_LIB_FUNCTION
      uint32_t *i_src;
      uint32_t w32;
#endif
      /* Truncate c to 8 bits */
      c = (c & 0xFF);

#ifdef CONFIG_OPT_LIB_FUNCTION
      /* Make a repeating word out of it */
      w32 = c;
      w32 |= w32 << 8;
      w32 |= w32 << 16;

      if (n >= 4) {
            /* Align the destination to a word boundary */
            /* This is done in an endian independant manner */
            switch ((unsigned) src & 3) {
            case 1:
                  *src++ = c;
                  --n;
            case 2:
                  *src++ = c;
                  --n;
            case 3:
                  *src++ = c;
                  --n;
            }

            i_src  = (void *)src;

            /* Do as many full-word copies as we can */
            for (; n >= 4; n -= 4)
                  *i_src++ = w32;

            src  = (void *)i_src;
      }
#endif
      /* Simple, byte oriented memset or the rest of count. */
      while (n--)
            *src++ = c;

      return v_src;
}
EXPORT_SYMBOL(memset);
#endif /* __HAVE_ARCH_MEMSET */

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