!  Useful routine: unsigned comparison (for addresses in Z-machine)
!    Returns 1 if x>y, 0 if x=y, -1 if x<y
! ----------------------------------------------------------------------------

[ UnsignedCompare x y u v;
  if (x==y) return 0;
  if (x<0 && y>=0) return 1;
  if (x>=0 && y<0) return -1;
  u = x&$7fff; v= y&$7fff;
  if (u>v) return 1;
  return -1;
];