(* The converse is not quite true, because "readable" does constraint to NoneP *)
(* NOT TRUE, because of CompCert_AV.valid problems. Lemma jam_con: forall A (S: A -> Prop) P Q, allp (jam S P Q) |-- allp (jam S P (fun _ => emp)) * (allp (jam S (fun _ => emp) Q)). *)

Lemma address_mapsto_VALspec:
forall ch v sh l i, 0 <= i < size_chunk ch ->
address_mapsto ch v sh l |-- VALspec sh (adr_add l i) * TT.