Definition is_defchar (mv: memval) :=
  match mv with
    | Byte _ => True
    | _ => False
  end.Inductive extcall_storebytes_sem
  (F V: Type) (ge: Genv.t F V): list memval -> list val -> mem -> trace -> val -> mem -> Prop :=
  | extcall_storebytes_sem_intro: forall (b: block) (ofs: int) bytes m m',
      Zlength bytes > 0 ->
      Forall is_defchar bytes ->
      Mem.storebytes m b (Int.unsigned ofs) bytes = Some m' ->
      extcall_storebytes_sem ge bytes (Vptr b ofs :: nil) m E0 Vundef m'.Inductive extcall_storebytes_sem
  (F V: Type) (ge: Genv.t F V): list memval -> list val -> mem -> trace -> val -> mem -> Prop :=
  | extcall_storebytes_sem_intro: forall (b: block) (ofs: int) bytes m m',
      Zlength bytes > 0 ->
      Forall is_defchar bytes ->
      Mem.storebytes m b (Int.unsigned ofs) bytes = Some m' ->
      extcall_storebytes_sem ge bytes (Vptr b ofs :: nil) m E0 Vundef m'.

Lemma storebytes_sem_inject_comm: forall F V (ge: Genv.t F V) m1 m1' m2 bytes b ofs j b' delta, Mem.storebytes m1 b (Int.unsigned ofs) bytes = Some m1' -> Zlength bytes > 0 -> Forall is_defchar bytes -> meminj_preserves_globals ge j -> Mem.inject j m1 m2 -> j b = Some (b', delta) -> exists m2', Mem.storebytes m2 b' (Int.unsigned (Int.add ofs (Int.repr delta))) bytes = Some m2' /\ Mem.inject j m1' m2' /\ Mem.unchanged_on (loc_unmapped j) m1 m1' /\ Mem.unchanged_on (loc_out_of_reach j m1) m2 m2'.