//
// 64-bit "compare-exchange" operations are slow on Broadwell
//

//
// 32-BIT -- SUPER FAST
//
  {
    const uint  t = min(r1  ,r2  );
    r2            = max(r1  ,r2  );
    r1            = t;
  }

//
// 64-BIT -- SLOW
//
  {
    const ulong t = min(r1  ,r2  );
    r2            = max(r1  ,r2  );
    r1            = t;
  }

//
// 64-BIT -- SLOW BUT SLIGHTLY FASTER
//
  if (r1 > r2) {
    const ulong t = r2;
    r2            = r1;
    r1            = t;
  }