Definition regset_wd rs : Prop :=
      forall r, valid_val f (Pregmap.get r rs).Definition core_wd c : Prop :=
      match c with State rs _ => regset_wd rs end.Definition ge_wd (the_ge: genv) : Prop :=
      (forall b, Maps.PTree.get b (genv_defs the_ge) ->
            f b) /\
      (forall id ofs v, Senv.symbol_address the_ge id ofs = v ->
                   valid_val f v).

Lemma longofwords_valid_val: forall f v1 v2, valid_val f v1 -> valid_val f v2 -> valid_val f (Val.longofwords v1 v2).