(** Pointer operations *)
Definition offset_ptr (v: aval) (n: ptrofs) :=
match v with
| Ptr p => Ptr (padd p n)
| Ifptr p => Ifptr (padd p n)
| _ => ntop1 v
end.

Lemma offset_ptr_sound:
forall v x n, vmatch v x -> vmatch (Val.offset_ptr v n) (offset_ptr x n).