(** Expressing 64-bit operations in terms of 32-bit operations *)

Lemma decompose_shl_1:
forall xh xl y,
0 <= Int.unsigned y < Int.zwordsize ->
shl' (ofwords xh xl) y =
ofwords (Int.or (Int.shl xh y) (Int.shru xl (Int.sub Int.iwordsize y)))
(Int.shl xl y).