text: /*******************************************************************************
   *
   * Copyright (C) 2014-2018 Wave Computing, Inc.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   *
   * 1. Redistributions of source code must retain the above copyright notice,
   * this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright notice,
   * this list of conditions and the following disclaimer in the documentation
   * and/or other materials provided with the distribution.
   * 3. Neither the name of the copyright holder nor the names of its
   * contributors may be used to endorse or promote products derived from this
   * software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   ******************************************************************************/
  
  #include <string.h>
  #include "low/_flavour.h"
  
  void *
  memmove (void *dst_void, const void* src_void, size_t length)
  {
    char *dst = (char *)dst_void;
    const  char *src = (const char *)src_void;
  
    if (src >= dst)
      {
  
  #ifndef __PREFER_SIZE_OVER_SPEED__
      long *aligned_dst;
      const long *aligned_src;
      int blocksize = sizeof (long) << 1;
          
      /* Use optimizing algorithm for a non-destructive copy to closely 
      match memcpy. If the size is small or either SRC or DST is unaligned,
      then punt into the byte copy loop.  This should be rare.  */
      if (length >= blocksize  && 
          !(((long)src & (sizeof (long) - 1)) |
            ((long)dst & (sizeof (long) - 1))))
        {
          aligned_dst = (long*)dst;
          aligned_src = (long*)src;
  
          /* Copy 4X long words at a time if possible.  */
          while (length >= blocksize)
            {
              *aligned_dst++ = *aligned_src++;
              *aligned_dst++ = *aligned_src++;
              length -= blocksize;
            }
  
          /* Pick up any residual with a byte copier.  */
          dst = (char*)aligned_dst;
          src = (char*)aligned_src;
        }
  
  #endif /* __PREFER_SIZE_OVER_SPEED__ */  
  
        while (length)
          {
            *dst++ = *src++;
  	  --length;
          }
      }
      
  /* Destructive overlap, copy backwards */
    else
      {
        while (length)	    
        {
          --length;
  	dst[length] = src[length];	      
        }
        	    
      }	    
  
    return dst_void;
  }
  