(** Useful properties of the PC register. *)

(* Specifications: *)
Lemma nextinstr_nf_inv:
forall r rs,
match r with PC => False | CR _ => False | _ => True end ->
(nextinstr_nf rs)#r = rs#r.
Lemma nextinstr_nf_inv1:
forall r rs,
data_preg r = true -> (nextinstr_nf rs)#r = rs#r.
Lemma nextinstr_nf_set_preg:
forall rs m v,
(nextinstr_nf (rs#(preg_of m) <- v))#PC = Val.offset_ptr rs#PC Ptrofs.one.