Definition longofwords (x y: aval) :=
match y, x with
| I j, I i => L(Int64.ofwords i j)
| _, _     => ntop2 x y
end.

(* Specifications: *)
Lemma longofwords_sound:
forall v w x y, vmatch v x -> vmatch w y -> vmatch (Val.longofwords v w) (longofwords x y).