text: #include <string.h>
  
  void *
  memmove(void *s1, const void *s2, size_t n)
  {
  	char *cs1;
  	const char *cs2;
  
  	cs1 = (char *)s1;
  	cs2 = (const char *)s2;
  	if (cs1 == cs2)
  	{
  		return (s1);
  	}
  	else 
  	{
  		for (; n > 0; --n)
  		{
  			*cs1++ = *cs2++;
  		}
  	}
  	return (s1);
  }
  