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kernel/linux-imx6_3.14.28/arch/microblaze/lib/memset.c 2.37 KB
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  /*
   * 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, unsuccessfully, 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/export.h>
  #include <linux/types.h>
  #include <linux/stddef.h>
  #include <linux/compiler.h>
  #include <linux/string.h>
  
  #ifdef __HAVE_ARCH_MEMSET
  #ifndef CONFIG_OPT_LIB_FUNCTION
  void *memset(void *v_src, int c, __kernel_size_t n)
  {
  	char *src = v_src;
  
  	/* Truncate c to 8 bits */
  	c = (c & 0xFF);
  
  	/* Simple, byte oriented memset or the rest of count. */
  	while (n--)
  		*src++ = c;
  
  	return v_src;
  }
  #else /* CONFIG_OPT_LIB_FUNCTION */
  void *memset(void *v_src, int c, __kernel_size_t n)
  {
  	char *src = v_src;
  	uint32_t *i_src;
  	uint32_t w32 = 0;
  
  	/* Truncate c to 8 bits */
  	c = (c & 0xFF);
  
  	if (unlikely(c)) {
  		/* Make a repeating word out of it */
  		w32 = c;
  		w32 |= w32 << 8;
  		w32 |= w32 << 16;
  	}
  
  	if (likely(n >= 4)) {
  		/* Align the destination to a word boundary */
  		/* This is done in an endian independent 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;
  	}
  
  	/* Simple, byte oriented memset or the rest of count. */
  	while (n--)
  		*src++ = c;
  
  	return v_src;
  }
  #endif /* CONFIG_OPT_LIB_FUNCTION */
  EXPORT_SYMBOL(memset);
  #endif /* __HAVE_ARCH_MEMSET */