(** Validity of a list of registers. *)

Definition regs_valid (rl: list reg) (s: state) : Prop :=
  forall r, In r rl -> reg_valid r s.

Lemma regs_valid_app: forall rl1 rl2 s, regs_valid rl1 s -> regs_valid rl2 s -> regs_valid (rl1 ++ rl2) s.