Remark int64_shru'_div_two_p:
  forall x y, Int64.shru' x y = Int64.repr (Int64.unsigned x / two_p (Int.unsigned y)).

Theorem divlu_mul_shift: forall x y m p, divlu_mul_params (Int64.unsigned y) = Some(p, m) -> 0 <= p < 64 /\ Int64.divu x y = Int64.shru' (Int64.mulhu x (Int64.repr m)) (Int.repr p).