proposition: Lemma wordToN_NToWord_eqn: forall sz (n : N), wordToN (NToWord sz n) = (n mod Npow2 sz)%N.
proof: Proof. intros. pose proof (Npow2_not_zero sz). apply Nnat.N2Nat.inj. rewrite wordToN_to_nat. rewrite N2Nat.inj_mod by assumption. rewrite Npow2_nat. rewrite <- wordToNat_natToWord_eqn. rewrite <- NToWord_nat. reflexivity. Qed.
imports: Coq.Classes.Morphisms Coq.Classes.Morphisms_Prop Coq.Classes.Equivalence Coq.Arith.PeanoNat Coq.ZArith.BinInt  Coq.Arith.Arith Coq.NArith.NArith Coq.Bool.Bool Coq.ZArith.ZArith Coq.Logic.Eqdep_dec Coq.Logic.EqdepFacts Coq.Program.Tactics Coq.Program.Equality Coq.setoid_ring.Ring Coq.setoid_ring.Ring_polynom bbv.Nomega bbv.ZLib bbv.NatLib bbv.NLib bbv.N_Z_nat_conversions bbv.DepEq bbv.DepEqNat bbv.ReservedNotations Coq.micromega.Lia