(** 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_incr: forall s1 s2 rl, state_incr s1 s2 -> regs_valid rl s1 -> regs_valid rl s2.