Remark eqm_mul_2p32:
  forall x y, Int.eqm x y -> eqm (x * two_p 32) (y * two_p 32).

Lemma decompose_bitwise_binop: forall f f64 f32 xh xl yh yl, (forall x y i, 0 <= i < zwordsize -> testbit (f64 x y) i = f (testbit x i) (testbit y i)) -> (forall x y i, 0 <= i < Int.zwordsize -> Int.testbit (f32 x y) i = f (Int.testbit x i) (Int.testbit y i)) -> f64 (ofwords xh xl) (ofwords yh yl) = ofwords (f32 xh yh) (f32 xl yl).