Definition of_optbool (ab: abool) : aval :=
  match ab with
  | Just b => I (if b then Int.one else Int.zero)
  | _ => Uns Pbot 1
  end.

(* Specifications: *)
Lemma of_optbool_sound: forall ob ab, cmatch ob ab -> vmatch (Val.of_optbool ob) (of_optbool ab).