#include "byte.h"int byte_diff(s,n,t)register char *s;register unsigned int n;register char *t;{  for (;;) {    if (!n) return 0; if (*s != *t) break; ++s; ++t; --n;    if (!n) return 0; if (*s != *t) break; ++s; ++t; --n;    if (!n) return 0; if (*s != *t) break; ++s; ++t; --n;    if (!n) return 0; if (*s != *t) break; ++s; ++t; --n;  }  return ((int)(unsigned int)(unsigned char) *s)       - ((int)(unsigned int)(unsigned char) *t);}