(** Injections on registers *)

  Definition reg_ren f (r:PregEq.t) (rs rs' : regset) : Prop :=
    val_obs f (Pregmap.get r rs) (Pregmap.get r rs').Definition regset_ren f rs rs' : Prop :=
    forall r, reg_ren f r rs rs'.Definition core_inj f c c' :=
    match c, c' with State rs _, State rs' _ => regset_ren f rs rs' end.

Lemma extcall_arguments_ren: forall f m m' ef args rs rs' (Hexternal: extcall_arguments rs m (ef_sig ef) args) (Hmem_obs_eq: mem_obs_eq f m m') (Hrs_ren: regset_ren f rs rs'), exists args', extcall_arguments rs' m' (ef_sig ef) args' /\ val_obs_list f args args'.