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(* 02110-1301 USA                                                     *)
(* Contribution to the Coq Library   V6.3 (July 1999)                    *)
(****************************************************************)
(*           The Calculus of Inductive Constructions            *)
(*                       COQ v5.10                              *)
(*                                                              *)
(* Laurent Arditi.  Laboratoire I3S. CNRS ura 1376.             *)
(* Universite de Nice - Sophia Antipolis                        *)
(* arditi@unice.fr, http://wwwi3s.unice.fr/~arditi/lolo.html    *)
(*                                                              *)
(* date: november 1995                                          *)
(* file: Fill_defs                                              *)
(* contents: proof of a memory block instruction: Fills cx words*)
(* in memory starting at address di with value al.              *)
(* Definitions of operators, sizes...                           *)
(****************************************************************)
Require Export IncrDecr.
Require Export Memo.
Parameter a_size d_size : nat.  (* address and data sizes *)
Parameter di_init cx_init al_init : BV.
Parameter mem_init : Memo.
Fixpoint IsNull (v : BV) : bool :=
match v return bool with
| nil => true
| b :: w =>
match b return bool with
| true => false
| false => IsNull w
end
end.
auto.
Qed.
simple induction a. simpl in |- *. auto. trivial.
Qed.
simple induction a. simpl in |- *. intros. absurd (false = true).
auto. exact H. intros v. auto.
Qed.
simple induction n. simpl in |- *. trivial.
intros. simpl in |- *. exact H.
Qed.

Lemma IsNull_BV_null :
forall v : BV, IsNull v = true -> v = BV_null (lengthbv v).