dt_shift_128
dt_shift_128(tmp, -1);
dt_shift_128(tmp, -1);
dt_shift_128(tmp, 32);
dt_shift_128(tmp, 32);
dt_shift_128(subtrahend, 128 - log);
dt_shift_128(mask, 128 - log);
dt_shift_128(subtrahend, -1);
dt_shift_128(mask, -1);
dt_shift_128(next_pair, -pair_shift);
dt_shift_128(diff, 2);
dt_shift_128(next_try, 2);
dt_shift_128(result, 1);
dt_shift_128(result, 1);