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