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

Lemma decompose_shr_1: forall xh xl y, 0 <= Int.unsigned y < Int.zwordsize -> shr' (ofwords xh xl) y = ofwords (Int.shr xh y) (Int.or (Int.shru xl y) (Int.shl xh (Int.sub Int.iwordsize y))).