1/* Public domain. */
 2
 3#include "str.h"
 4
 5int str_diff(register const char *s,register const char *t)
 6{
 7  register char x;
 8
 9  for (;;) {
10    x = *s; if (x != *t) break; if (!x) break; ++s; ++t;
11    x = *s; if (x != *t) break; if (!x) break; ++s; ++t;
12    x = *s; if (x != *t) break; if (!x) break; ++s; ++t;
13    x = *s; if (x != *t) break; if (!x) break; ++s; ++t;
14  }
15  return ((int)(unsigned int)(unsigned char) x)
16       - ((int)(unsigned int)(unsigned char) *t);
17}