Definition poffset (p: aptr) : aptr :=
match p with
| Gl id ofs => Glo id
| Stk ofs => Stack
| _ => p
end.

(* Specifications: *)
Lemma poffset_sound:
forall b ofs1 ofs2 p,
pmatch b ofs1 p ->
pmatch b ofs2 (poffset p).