Definition value_of_hist (h : hist) := value_of (snd (last h (O, Store (vint 0)))).

Lemma ordered_last_value : forall h v (Hordered : ordered_hist h), last_value h v <-> value_of_hist h = v.
Definition wf_map (m : list (Z * Z)) := Forall (fun i => repable_signed i /\ i <> 0) (map fst m).