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-
-(*************************************************************)
-(* This file is distributed under the terms of the *)
-(* GNU Lesser General Public License Version 2.1 *)
-(*************************************************************)
-(* Benjamin.Gregoire@inria.fr Laurent.Thery@inria.fr *)
-(*************************************************************)
-
-Set Implicit Arguments.
-
-Require Import DoubleBase DoubleSub DoubleMul DoubleSqrt DoubleLift DoubleDivn1 DoubleDiv.
-Require Import CyclicAxioms DoubleCyclic BigN Cyclic31.
-Require Import ZArith ZCAux.
-Import CyclicAxioms DoubleType DoubleBase.
-
-Theorem Zpos_pos: forall x, 0 < Zpos x.
-red; simpl; auto.
-Qed.
-Hint Resolve Zpos_pos: zarith.
-
-Section Mod_op.
-
- Variable w : Type.
-
- Record mod_op : Type := mk_mod_op {
- succ_mod : w -> w;
- add_mod : w -> w -> w;
- pred_mod : w -> w;
- sub_mod : w -> w -> w;
- mul_mod : w -> w -> w;
- square_mod : w -> w;
- power_mod : w -> positive -> w
- }.
-
- Variable w_op : ZnZ.Ops w.
-
- Let w_digits := w_op.(ZnZ.digits).
- Let w_zdigits := w_op.(ZnZ.zdigits).
- Let w_to_Z := (@ZnZ.to_Z _ w_op).
- Let w_of_pos := (@ZnZ.of_pos _ w_op).
- Let w_head0 := (@ZnZ.head0 _ w_op).
- Let w0 := (@ZnZ.zero _ w_op).
- Let w1 := (@ZnZ.one _ w_op).
- Let wBm1 := (@ZnZ.minus_one _ w_op).
-
- Let wWW := (@ZnZ.WW _ w_op).
- Let wW0 := (@ZnZ.WO _ w_op).
- Let w0W := (@ZnZ.OW _ w_op).
-
- Let w_compare := (@ZnZ.compare _ w_op).
- Let w_opp_c := (@ZnZ.opp_c _ w_op).
- Let w_opp := (@ZnZ.opp _ w_op).
- Let w_opp_carry := (@ZnZ.opp_carry _ w_op).
-
- Let w_succ := (@ZnZ.succ _ w_op).
- Let w_succ_c := (@ZnZ.succ_c _ w_op).
- Let w_add_c := (@ZnZ.add_c _ w_op).
- Let w_add_carry_c := (@ZnZ.add_carry_c _ w_op).
- Let w_add := (@ZnZ.add _ w_op).
-
-
- Let w_pred_c := (@ZnZ.pred_c _ w_op).
- Let w_sub_c := (@ZnZ.sub_c _ w_op).
- Let w_sub_carry := (@ZnZ.sub_carry _ w_op).
- Let w_sub_carry_c := (@ZnZ.sub_carry_c _ w_op).
- Let w_sub := (@ZnZ.sub _ w_op).
- Let w_pred := (@ZnZ.pred _ w_op).
-
- Let w_mul_c := (@ZnZ.mul_c _ w_op).
- Let w_mul := (@ZnZ.mul _ w_op).
- Let w_square_c := (@ZnZ.square_c _ w_op).
-
- Let w_div21 := (@ZnZ.div21 _ w_op).
- Let w_add_mul_div := (@ZnZ.add_mul_div _ w_op).
-
- Variable b : w.
- (* b should be > 1 *)
- Let n := w_head0 b.
-
- Let b2n := w_add_mul_div n b w0.
-
- Let bm1 := w_sub b w1.
-
- Let mb := w_opp b.
-
- Let wwb := WW w0 b.
-
- Let low x := match x with WW _ x => x | W0 => w0 end.
-
- Let w_add2 x y := match w_add_c x y with
- C0 n => WW w0 n
- |C1 n => WW w1 n
- end.
- Let ww_zdigits := w_add2 w_zdigits w_zdigits.
-
- Let ww_compare :=
- Eval lazy beta delta [ww_compare] in ww_compare w0 w_compare.
-
- Let ww_sub :=
- Eval lazy beta delta [ww_sub] in
- ww_sub w0 wWW w_opp_c w_opp_carry w_sub_c w_opp w_sub w_sub_carry.
-
- Let ww_add_mul_div :=
- Eval lazy beta delta [ww_add_mul_div] in
- ww_add_mul_div w0 wWW wW0 w0W
- ww_compare w_add_mul_div
- ww_sub w_zdigits low (w0W n).
-
- Let ww_lsl_n :=
- Eval lazy beta delta [ww_add_mul_div] in
- fun ww => ww_add_mul_div ww W0.
-
- Let w_lsr_n w :=
- w_add_mul_div (w_sub w_zdigits n) w0 w.
-
- Open Scope Z_scope.
- Notation "[| x |]" :=
- (@ZnZ.to_Z _ w_op x) (at level 0, x at level 99).
-
-Notation "[[ x ]]" :=
- (@ww_to_Z _ w_digits w_to_Z x) (at level 0, x at level 99).
-
- Section Mod_spec.
-
- Variable m_op : mod_op.
-
- Record mod_spec : Prop := mk_mod_spec {
- succ_mod_spec :
- forall w t, [|w|]= t mod [|b|] ->
- [|succ_mod m_op w|] = ([|w|] + 1) mod [|b|];
- add_mod_spec :
- forall w1 w2 t1 t2, [|w1|]= t1 mod [|b|] -> [|w2|]= t2 mod [|b|] ->
- [|add_mod m_op w1 w2|] = ([|w1|] + [|w2|]) mod [|b|];
- pred_mod_spec :
- forall w t, [|w|]= t mod [|b|] ->
- [|pred_mod m_op w|] = ([|w|] - 1) mod [|b|];
- sub_mod_spec :
- forall w1 w2 t1 t2, [|w1|]= t1 mod [|b|] -> [|w2|]= t2 mod [|b|] ->
- [|sub_mod m_op w1 w2|] = ([|w1|] - [|w2|]) mod [|b|];
- mul_mod_spec :
- forall w1 w2 t1 t2, [|w1|]= t1 mod [|b|] -> [|w2|]= t2 mod [|b|] ->
- [|mul_mod m_op w1 w2|] = ([|w1|] * [|w2|]) mod [|b|];
- square_mod_spec :
- forall w t, [|w|]= t mod [|b|] ->
- [|square_mod m_op w|] = ([|w|] * [|w|]) mod [|b|];
- power_mod_spec :
- forall w t p, [|w|]= t mod [|b|] ->
- [|power_mod m_op w p|] = (Zpower_pos [|w|] p) mod [|b|]
-(*
- shift_spec :
- forall w p, wf w ->
- [|shift m_op w p|] = ([|w|] / (Zpower_pos 2 p)) mod [|b|];
- trunc_spec :
- forall w p, wf w ->
- [|power_mod m_op w p|] = ([|w1|] mod (Zpower_pos 2 p)) mod [|b|]
-*)
- }.
-
- End Mod_spec.
-
- Hypothesis b_pos: 1 < [|b|].
- Variable op_spec: ZnZ.Specs w_op.
-
-
- Lemma Zpower_n: 0 < 2 ^ [|n|].
- apply Zpower_gt_0; auto with zarith.
- case (ZnZ.spec_to_Z n); auto with zarith.
- Qed.
-
- Hint Resolve Zpower_n Zmult_lt_0_compat Zpower_gt_0.
-
- Variable m_op : mod_op.
-
- Hint Rewrite
- ZnZ.spec_0
- ZnZ.spec_1
- ZnZ.spec_m1
- ZnZ.spec_WW
- ZnZ.spec_opp_c
- ZnZ.spec_opp
- ZnZ.spec_opp_carry
- ZnZ.spec_succ_c
- ZnZ.spec_add_c
- ZnZ.spec_add_carry_c
- ZnZ.spec_add
- ZnZ.spec_pred_c
- ZnZ.spec_sub_c
- ZnZ.spec_sub_carry_c
- ZnZ.spec_sub
- ZnZ.spec_mul_c
- ZnZ.spec_mul
- : w_rewrite.
-
- Let _succ_mod x :=
- let res :=w_succ x in
- match w_compare res b with
- | Lt => res
- | _ => w0
- end.
-
- Let split x :=
- match x with
- | W0 => (w0,w0)
- | WW h l => (h,l)
- end.
-
- Let _w0_is_0: [|w0|] = 0.
- unfold ZnZ.to_Z; rewrite <- ZnZ.spec_0; auto.
- Qed.
-
- Let _w1_is_1: [|w1|] = 1.
- unfold ZnZ.to_Z; rewrite <-ZnZ.spec_1; simpl; auto.
- Qed.
-
- Theorem Zmod_plus_one: forall a1 b1, 0 < b1 -> (a1 + b1) mod b1 = a1 mod b1.
- intros a1 b1 H; rewrite Zplus_mod; auto with zarith.
- rewrite Z_mod_same; try rewrite Zplus_0_r; auto with zarith.
- apply Zmod_mod; auto.
- Qed.
-
- Theorem Zmod_minus_one: forall a1 b1, 0 < b1 -> (a1 - b1) mod b1 = a1 mod b1.
- intros a1 b1 H; rewrite Zminus_mod; auto with zarith.
- rewrite Z_mod_same; try rewrite Zminus_0_r; auto with zarith.
- apply Zmod_mod; auto.
- Qed.
-
- Lemma without_c_b: forall w2, [|w2|] < [|b|] ->
- [|w_succ w2|] = [|w2|] + 1.
- intros w2 H.
- unfold w_succ;rewrite ZnZ.spec_succ.
- rewrite Zmod_small;auto.
- assert (HH := ZnZ.spec_to_Z w2).
- assert (HH' := ZnZ.spec_to_Z b);auto with zarith.
- Qed.
-
- Lemma _succ_mod_spec: forall w t, [|w|]= t mod [|b|] ->
- [|_succ_mod w|] = ([|w|] + 1) mod [|b|].
- intros w2 t H; unfold _succ_mod, w_compare; simpl.
- assert (F: [|w2|] < [|b|]).
- case (Z_mod_lt t [|b|]); auto with zarith.
- rewrite ZnZ.spec_compare; case Zcompare_spec; intros H1;
- match goal with H: context[w_succ _] |- _ =>
- generalize H; clear H; rewrite (without_c_b _ F); intros H1;
- auto with zarith
- end.
- rewrite H1, Z_mod_same, _w0_is_0; auto with zarith.
- rewrite Zmod_small; auto with zarith.
- case (ZnZ.spec_to_Z w2); auto with zarith.
- Qed.
-
- Let _add_mod x y :=
- match w_add_c x y with
- | C0 z =>
- match w_compare z b with
- | Lt => z
- | Eq => w0
- | Gt => w_sub z b
- end
- | C1 z => w_add mb z
- end.
-
- Lemma _add_mod_correct: forall w1 w2, [|w1|] + [|w2|] < 2 * [|b|] ->
- [|_add_mod w1 w2|] = ([|w1|] + [|w2|]) mod [|b|].
- intros w2 w3; unfold _add_mod, w_compare, w_add_c; intros H.
- match goal with |- context[ZnZ.add_c ?x ?y] =>
- generalize (ZnZ.spec_add_c x y); unfold interp_carry;
- case (ZnZ.add_c x y); autorewrite with w_rewrite
- end; auto with zarith.
- intros w4 H2.
- rewrite ZnZ.spec_compare; case Zcompare_spec; intros H1;
- match goal with H: context[b] |- _ =>
- generalize H; clear H; intros H1; rewrite <-H2;
- auto with zarith
- end.
- rewrite H1, Z_mod_same; auto with zarith.
- rewrite Zmod_small; auto with zarith.
- case (ZnZ.spec_to_Z w4); auto with zarith.
- assert (F1: 0 < [|w4|] - [|b|]); auto with zarith.
- assert (F2: [|w4|] < [|b|] + [|b|]); auto with zarith.
- autorewrite with w_rewrite; auto.
- rewrite (fun x y => Zmod_small (x - y)); auto with zarith.
- rewrite <- (Zmod_minus_one [|w4|]); auto with zarith.
- apply sym_equal; apply Zmod_small; auto with zarith.
- split; auto with zarith.
- apply Zlt_trans with [|b|]; auto with zarith.
- case (ZnZ.spec_to_Z b); unfold base; auto with zarith.
- rewrite Zmult_1_l; intros w4 H2; rewrite <- H2.
- unfold mb, w_add; rewrite ZnZ.spec_add; auto with zarith.
- assert (F1: [|w4|] < [|b|]).
- assert (F2: base (ZnZ.digits w_op) + [|w4|] < base (ZnZ.digits w_op) + [|b|]);
- auto with zarith.
- rewrite H2.
- apply Zlt_trans with ([|b|] +[|b|]); auto with zarith.
- apply Zplus_lt_compat_r; auto with zarith.
- case (ZnZ.spec_to_Z b); auto with zarith.
- assert (F2: [|b|] < base (ZnZ.digits w_op) + [|w4|]); auto with zarith.
- apply Zlt_le_trans with (base (ZnZ.digits w_op)); auto with zarith.
- case (ZnZ.spec_to_Z b); auto with zarith.
- case (ZnZ.spec_to_Z w4); auto with zarith.
- assert (F3: base (ZnZ.digits w_op) + [|w4|] < [|b|] + [|b|]); auto with zarith.
- rewrite <- (fun x => Zmod_minus_one (base x + [|w4|])); auto with zarith.
- rewrite (fun x y => Zmod_small (x - y)); auto with zarith.
- unfold w_opp;rewrite (ZnZ.spec_opp b).
- rewrite <- (fun x => Zmod_plus_one (-x)); auto with zarith.
- rewrite (Zmod_small (- [|b|] + base (ZnZ.digits w_op)));auto with zarith.
- 2 : assert (HHH := ZnZ.spec_to_Z b);auto with zarith.
- repeat rewrite Zmod_small; auto with zarith.
- Qed.
-
- Lemma _add_mod_spec: forall w1 w2 t1 t2, [|w1|] = t1 mod [|b|] -> [|w2|] = t2 mod [|b|] ->
- [|_add_mod w1 w2|] = ([|w1|] + [|w2|]) mod [|b|].
- intros w2 w3 t1 t2 H H1.
- apply _add_mod_correct; auto with zarith.
- assert (F: [|w2|] < [|b|]).
- case (Z_mod_lt t1 [|b|]); auto with zarith.
- assert (F': [|w3|] < [|b|]).
- case (Z_mod_lt t2 [|b|]); auto with zarith.
- assert (tmp: forall x, 2 * x = x + x); auto with zarith.
- Qed.
-
- Let _pred_mod x :=
- match w_compare w0 x with
- | Eq => bm1
- | _ => w_pred x
- end.
-
- Lemma _pred_mod_spec: forall w t, [|w|] = t mod [|b|] ->
- [|_pred_mod w|] = ([|w|] - 1) mod [|b|].
- intros w2 t H; unfold _pred_mod, w_compare, bm1; simpl.
- assert (F: [|w2|] < [|b|]).
- case (Z_mod_lt t [|b|]); auto with zarith.
- rewrite ZnZ.spec_compare; case Zcompare_spec; intros H1;
- match goal with H: context[w2] |- _ =>
- generalize H; clear H; intros H1; autorewrite with w_rewrite;
- auto with zarith
- end; try rewrite _w0_is_0; try rewrite _w1_is_1; auto with zarith.
- rewrite <- H1, _w0_is_0; simpl.
- rewrite <- (Zmod_plus_one (-1)); auto with zarith.
- repeat rewrite Zmod_small; auto with zarith.
- case (ZnZ.spec_to_Z b); auto with zarith.
- unfold w_pred;rewrite ZnZ.spec_pred; auto.
- assert (HHH := ZnZ.spec_to_Z b);repeat rewrite Zmod_small;auto with
- zarith.
- intros;assert (HHH := ZnZ.spec_to_Z w2);auto with zarith.
- Qed.
-
- Let _sub_mod x y :=
- match w_sub_c x y with
- | C0 z => z
- | C1 z => w_add z b
- end.
-
- Lemma _sub_mod_spec: forall w1 w2 t1 t2, [|w1|] = t1 mod [|b|] -> [|w2|] = t2 mod [|b|] ->
- [|_sub_mod w1 w2|] = ([|w1|] - [|w2|]) mod [|b|].
- intros w2 w3 t1 t2; unfold _sub_mod, w_compare, w_sub_c; intros H H1.
- assert (F: [|w2|] < [|b|]).
- case (Z_mod_lt t1 [|b|]); auto with zarith.
- assert (F': [|w3|] < [|b|]).
- case (Z_mod_lt t2 [|b|]); auto with zarith.
- match goal with |- context[ZnZ.sub_c ?x ?y] =>
- generalize (ZnZ.spec_sub_c x y); unfold interp_carry;
- case (ZnZ.sub_c x y); autorewrite with w_rewrite
- end; auto with zarith.
- intros w4 H2.
- rewrite Zmod_small; auto with zarith.
- split; auto with zarith.
- rewrite <- H2; case (ZnZ.spec_to_Z w4); auto with zarith.
- apply Zle_lt_trans with [|w2|]; auto with zarith.
- case (ZnZ.spec_to_Z w3); auto with zarith.
- intros w4 H2; rewrite <- H2.
- unfold w_add; rewrite ZnZ.spec_add; auto with zarith.
- case (ZnZ.spec_to_Z w4); intros F1 F2.
- assert (F3: 0 <= - 1 * base (ZnZ.digits w_op) + [|w4|] + [|b|]); auto with zarith.
- rewrite H2.
- case (ZnZ.spec_to_Z w3); case (ZnZ.spec_to_Z w2); auto with zarith.
- rewrite <- (fun x => Zmod_minus_one ([|w4|] + x)); auto with zarith.
- rewrite <- (fun x y => Zmod_plus_one (-y + x)); auto with zarith.
- repeat rewrite Zmod_small; auto with zarith.
- case (ZnZ.spec_to_Z b); auto with zarith.
- Qed.
-
- Let _mul_mod x y :=
- let xy := w_mul_c x y in
- match ww_compare xy wwb with
- | Lt => snd (split xy)
- | Eq => w0
- | Gt =>
- let xy2n := ww_lsl_n xy in
- let (h,l) := split xy2n in
- let (q,r) := w_div21 h l b2n in
- w_lsr_n r
- end.
-
- Theorem high_zero:forall x, [[x]] < base w_digits -> [|fst (split x)|] = 0.
- intros x; case x; simpl; auto.
- intros xh xl H; case (Zle_lt_or_eq 0 [|xh|]); auto with zarith.
- case (ZnZ.spec_to_Z xh); auto with zarith.
- intros H1; contradict H; apply Zle_not_lt.
- assert (HHHH := wB_pos w_digits).
- unfold w_to_Z.
- match goal with |- ?X <= ?Y + ?Z =>
- pattern X at 1; rewrite <- (Zmult_1_l X); auto with zarith;
- apply Zle_trans with Y; auto with zarith
- end.
- case (ZnZ.spec_to_Z xl); auto with zarith.
- Qed.
-
- Theorem n_spec: base (ZnZ.digits w_op) / 2 <= 2 ^ [|n|] * [|b|]
- < base (ZnZ.digits w_op).
- unfold n, w_head0; apply (ZnZ.spec_head0); auto with zarith.
- Qed.
-
- Theorem b2n_spec: [|b2n|] = 2 ^ [|n|] * [|b|].
- unfold b2n, w_add_mul_div; case n_spec; intros Hp Hp1.
- assert (F1: [|n|] < Zpos (ZnZ.digits w_op)).
- case (Zle_or_lt (Zpos (ZnZ.digits w_op)) [|n|]); auto with zarith.
- intros H1; contradict Hp1; apply Zle_not_lt; unfold base.
- apply Zle_trans with (2 ^ [|n|] * 1); auto with zarith.
- rewrite Zmult_1_r; apply Zpower_le_monotone; auto with zarith.
- rewrite ZnZ.spec_add_mul_div; auto with zarith.
- rewrite _w0_is_0; rewrite Zdiv_0_l; auto with zarith.
- rewrite Zplus_0_r; rewrite Zmult_comm; apply Zmod_small; auto with zarith.
- Qed.
-
- Theorem ww_lsl_n_spec: forall w, [[w]] < [|b|] * [|b|] ->
- [[ww_lsl_n w]] = 2 ^ [|n|] * [[w]].
- intros w2 H; unfold ww_lsl_n.
- case n_spec; intros Hp Hp1.
- assert (F0: forall x, 2 * x = x + x); auto with zarith.
- assert (F1: [|n|] < Zpos (ZnZ.digits w_op)).
- case (Zle_or_lt (Zpos (ZnZ.digits w_op)) [|n|]); auto.
- intros H1; contradict Hp1; apply Zle_not_lt; unfold base.
- apply Zle_trans with (2 ^ [|n|] * 1); auto with zarith.
- rewrite Zmult_1_r; apply Zpower_le_monotone; auto with zarith.
- assert (F2: [|n|] < Zpos (xO (ZnZ.digits w_op))).
- rewrite (Zpos_xO (ZnZ.digits w_op)); rewrite F0; auto with zarith.
- pattern [|n|]; rewrite <- Zplus_0_r; auto with zarith.
- apply Zplus_lt_compat; auto with zarith.
- change
- ([[DoubleLift.ww_add_mul_div w0 wWW wW0 w0W
- ww_compare w_add_mul_div
- ww_sub w_zdigits low (w0W n) w2 W0]] = 2 ^ [|n|] * [[w2]]).
- rewrite (DoubleLift.spec_ww_add_mul_div ); auto with zarith.
- 2: apply ZnZ.spec_to_Z; auto.
- 2: refine (spec_ww_to_Z _ _ _); auto.
- 2: apply ZnZ.spec_to_Z; auto.
- 2: apply ZnZ.spec_WW; auto.
- 2: apply ZnZ.spec_WO; auto.
- 2: apply ZnZ.spec_OW; auto.
- 2: refine (spec_ww_compare _ _ _ _ _ _ _); auto.
- 2: apply ZnZ.spec_to_Z; auto.
- 2: apply ZnZ.spec_compare; auto.
- 2: apply ZnZ.spec_add_mul_div; auto.
- 2: refine (spec_ww_sub _ _ _ _ _ _ _ _ _ _
- _ _ _ _ _ _ _ _ _ _ _); auto.
- 2: apply ZnZ.spec_to_Z; auto.
- 2: apply ZnZ.spec_WW; auto.
- 2: apply ZnZ.spec_opp_c; auto.
- 2: apply ZnZ.spec_opp; auto.
- 2: apply ZnZ.spec_opp_carry; auto.
- 2: apply ZnZ.spec_sub_c; auto.
- 2: apply ZnZ.spec_sub; auto.
- 2: apply ZnZ.spec_sub_carry; auto.
- 2: apply ZnZ.spec_zdigits; auto.
- replace ([[w0W n]]) with [|n|].
- change [[W0]] with 0. rewrite Zdiv_0_l; auto with zarith.
- rewrite Zplus_0_r; rewrite Zmod_small; auto with zarith.
- split; auto with zarith.
- case spec_ww_to_Z with (w_digits := w_digits) (w_to_Z := w_to_Z) (x:=w2); auto with zarith.
- apply ZnZ.spec_to_Z; auto.
- apply Zlt_trans with ([|b|] * [|b|] * 2 ^ [|n|]); auto with zarith.
- apply Zmult_lt_compat_r; auto with zarith.
- rewrite <- Zmult_assoc.
- unfold base; unfold base in Hp.
- unfold ww_digits,w_digits;rewrite (Zpos_xO (ZnZ.digits w_op)); rewrite F0; auto with zarith.
- rewrite Zpower_exp; auto with zarith.
- apply Zmult_lt_compat; auto with zarith.
- case (ZnZ.spec_to_Z b); auto with zarith.
- split; auto with zarith.
- rewrite Zmult_comm; auto with zarith.
- unfold w_digits;auto with zarith.
- generalize (ZnZ.spec_OW n).
- unfold ww_to_Z, w_digits; auto.
- intros x; case x; simpl.
- unfold w_to_Z, w_digits, w0; rewrite ZnZ.spec_0; auto.
- intros w3 w4; rewrite Zplus_comm.
- rewrite Z_mod_plus; auto with zarith.
- rewrite Zmod_small; auto with zarith.
- case (ZnZ.spec_to_Z w4); auto with zarith.
- unfold base; auto with zarith.
- unfold ww_to_Z, w_digits, w_to_Z, w0W; auto.
- rewrite ZnZ.spec_OW; auto with zarith.
- Qed.
-
- Theorem w_lsr_n_spec: forall w, [|w|] < 2 ^ [|n|] * [|b|]->
- [|w_lsr_n w|] = [|w|] / 2 ^ [|n|].
- intros w2 H.
- case (ZnZ.spec_to_Z w2); intros U1 U2.
- unfold w_lsr_n, w_add_mul_div.
- rewrite ZnZ.spec_add_mul_div; auto with zarith.
- rewrite _w0_is_0; rewrite Zmult_0_l; auto with zarith.
- rewrite Zplus_0_l.
- autorewrite with w_rewrite; auto.
- rewrite (fun x y => Zmod_small (x - y)); auto with zarith.
- unfold w_zdigits; rewrite ZnZ.spec_zdigits; auto.
- assert (tmp: forall p q, p - (p - q) = q); intros; try ring;
- rewrite tmp; clear tmp; auto.
- rewrite Zmod_small; auto with zarith.
- split; auto with zarith.
- apply Zle_lt_trans with (2 := U2); auto with zarith.
- apply Zdiv_le_upper_bound; auto with zarith.
- apply Zle_trans with ([|w2|] * (2 ^ 0)); auto with zarith.
- simpl Zpower; rewrite Zmult_1_r; auto with zarith.
- apply Zmult_le_compat_l; auto with zarith.
- apply Zpower_le_monotone; auto with zarith.
- case (ZnZ.spec_to_Z n); auto with zarith.
- unfold n.
- assert (HH: 0 < [|b|]); auto with zarith.
- split.
- case (Zle_or_lt [|w_head0 b|] [|w_zdigits|]); auto with zarith.
- unfold w_zdigits; rewrite ZnZ.spec_zdigits; auto; intros H1.
- case (ZnZ.spec_head0 b HH); intros _ H2; contradict H2.
- apply Zle_not_lt; unfold base.
- apply Zle_trans with (2^[|ZnZ.head0 b|] * 1); auto with zarith.
- rewrite Zmult_1_r; apply Zpower_le_monotone; auto with zarith.
- unfold w_zdigits; rewrite ZnZ.spec_zdigits; auto.
- apply Zle_lt_trans with (Zpos (ZnZ.digits w_op)); auto with zarith.
- case (ZnZ.spec_to_Z (w_head0 b)); auto with zarith.
- unfold base; apply Zpower2_lt_lin; auto with zarith.
- autorewrite with w_rewrite; auto.
- rewrite Zmod_small; auto with zarith.
- unfold w_zdigits; rewrite ZnZ.spec_zdigits; auto with zarith.
- case (ZnZ.spec_to_Z n); auto with zarith.
- unfold w_zdigits; rewrite ZnZ.spec_zdigits; auto.
- split; auto with zarith.
- case (Zle_or_lt [|n|] (Zpos (ZnZ.digits w_op))); auto with zarith; intros H1.
- case (ZnZ.spec_head0 b); auto with zarith; intros _ H2.
- contradict H2; apply Zle_not_lt; auto with zarith.
- unfold base; apply Zle_trans with (2 ^ [|ZnZ.head0 b|] * 1);
- auto with zarith.
- rewrite Zmult_1_r; unfold base; apply Zpower_le_monotone; auto with zarith.
- apply Zle_lt_trans with (Zpos (ZnZ.digits w_op)); auto with zarith.
- case (ZnZ.spec_to_Z n); auto with zarith.
- unfold base; apply Zpower2_lt_lin; auto with zarith.
- Qed.
-
- Lemma split_correct: forall x, let (xh, xl) := split x in [[WW xh xl]] = [[x]].
- intros x; case x; simpl; unfold w0, w_to_Z;try rewrite ZnZ.spec_0; auto with zarith.
- Qed.
-
- Lemma _mul_mod_spec: forall w1 w2 t1 t2, [|w1|] = t1 mod [|b|] -> [|w2|] = t2 mod [|b|] ->
- [|_mul_mod w1 w2|] = ([|w1|] * [|w2|]) mod [|b|].
- intros w2 w3 t1 t2 H H1; unfold _mul_mod, wwb.
- assert (F: [|w2|] < [|b|]).
- case (Z_mod_lt t1 [|b|]); auto with zarith.
- assert (F': [|w3|] < [|b|]).
- case (Z_mod_lt t2 [|b|]); auto with zarith.
- match goal with |- context[ww_compare ?x ?y] =>
- change (ww_compare x y) with (DoubleBase.ww_compare w0 w_compare x y)
- end.
- rewrite (@spec_ww_compare w w0 w_digits w_to_Z w_compare
- ZnZ.spec_0 ZnZ.spec_to_Z ZnZ.spec_compare
- (w_mul_c w2 w3) (WW w0 b)); case Zcompare_spec; intros H2;
- match goal with H: context[w_mul_c] |- _ =>
- generalize H; clear H
- end; try rewrite _w0_is_0; try rewrite !_w1_is_1; auto with zarith.
- unfold w_mul_c, ww_to_Z, w_to_Z, w_digits; rewrite ZnZ.spec_mul_c; auto with zarith.
- simpl; rewrite _w0_is_0, Zmult_0_l, Zplus_0_l.
- intros H2; rewrite H2; simpl.
- rewrite Z_mod_same; auto with zarith.
- generalize (high_zero (w_mul_c w2 w3)).
- unfold w_mul_c; generalize (ZnZ.spec_mul_c w2 w3);
- case (ZnZ.mul_c w2 w3); simpl; auto with zarith.
- intros H3 _ _; rewrite <- H3; autorewrite with w_rewrite; auto.
-(* rewrite Zmod_small; auto with zarith. *)
- intros w4 w5.
- change (w_to_Z w0) with [|w0|]; rewrite _w0_is_0.
- change (w_to_Z w4) with [|w4|].
- change (w_to_Z w5) with [|w5|].
- simpl.
- intros H2 H3 H4.
- assert (E1: [|w4|] = 0).
- apply H3; auto with zarith.
- apply Zlt_trans with (1 := H4).
- case (ZnZ.spec_to_Z b); auto with zarith.
- generalize H4 H2; rewrite E1; rewrite Zmult_0_l; rewrite Zplus_0_l;
- clear H4 H2; intros H4 H2.
- rewrite <- H2; rewrite Zmod_small; auto with zarith.
- case (ZnZ.spec_to_Z w5); auto with zarith.
- intros H2.
- match goal with |- context[split ?x] =>
- generalize (split_correct x);
- case (split x); auto with zarith
- end.
- assert (F1: [[w_mul_c w2 w3]] < [|b|] * [|b|]).
- unfold w_to_Z, w_mul_c, ww_to_Z,w_digits;
- rewrite ZnZ.spec_mul_c; auto with zarith.
- apply Zmult_lt_compat; auto with zarith.
- case (ZnZ.spec_to_Z w2); auto with zarith.
- case (ZnZ.spec_to_Z w3); auto with zarith.
- intros w4 w5; rewrite ww_lsl_n_spec; auto with zarith.
- intros H3.
- unfold w_div21; match goal with |- context[ZnZ.div21 ?y ?z ?t] =>
- generalize (ZnZ.spec_div21 y z t);
- case (ZnZ.div21 y z t)
- end.
- rewrite b2n_spec; case (n_spec); auto.
- intros H4 H5 w6 w7 H6.
- case H6; auto with zarith.
- case (Zle_or_lt (2 ^ [|n|] * [|b|]) [|w4|]); auto; intros H7.
- match type of H3 with ?X = ?Y =>
- absurd (Y < X)
- end.
- apply Zle_not_lt; rewrite H3; auto with zarith.
- simpl ww_to_Z.
- match goal with |- ?X < ?Y + _ =>
- apply Zlt_le_trans with Y; auto with zarith
- end.
- apply Zlt_trans with (2 ^ [|n|] * ([|b|] * [|b|]));
- auto with zarith.
- apply Zmult_lt_compat_l; auto with zarith.
- rewrite Zmult_assoc.
- apply Zmult_lt_compat2; auto with zarith.
- case (ZnZ.spec_to_Z b); auto with zarith.
- case (ZnZ.spec_to_Z w5); unfold w_to_Z;auto with zarith.
- clear H6; intros H7 H8.
- rewrite w_lsr_n_spec; auto with zarith.
- rewrite <- (Z_div_mult ([|w2|] * [|w3|]) (2 ^ [|n|]));
- auto with zarith; rewrite Zmult_comm.
- rewrite <- ZnZ.spec_mul_c; auto with zarith.
- unfold w_mul_c in H3; unfold ww_to_Z in H3;simpl H3.
- unfold w_digits,w_to_Z in H3. rewrite <- H3; simpl.
- rewrite H7; rewrite (fun x => Zmult_comm (2 ^ x));
- rewrite Zmult_assoc; rewrite BigNumPrelude.Z_div_plus_l; auto with zarith.
- rewrite Zplus_mod; auto with zarith.
- rewrite Z_mod_mult; auto with zarith.
- rewrite Zplus_0_l; auto with zarith.
- rewrite Zmod_mod; auto with zarith.
- rewrite Zmod_small; auto with zarith.
- split; auto with zarith.
- apply Zdiv_lt_upper_bound; auto with zarith.
- rewrite Zmult_comm; auto with zarith.
- Qed.
-
- Let _square_mod x :=
- let x2 := w_square_c x in
- match ww_compare x2 wwb with
- | Lt => snd (split x2)
- | Eq => w0
- | Gt =>
- let x2_2n := ww_lsl_n x2 in
- let (h,l) := split x2_2n in
- let (q,r) := w_div21 h l b2n in
- w_lsr_n r
- end.
-
- Lemma _square_mod_spec: forall w t, [|w|] = t mod [|b|] ->
- [|_square_mod w|] = ([|w|] * [|w|]) mod [|b|].
- intros w2 t2 H; unfold _square_mod, wwb.
- assert (F: [|w2|] < [|b|]).
- case (Z_mod_lt t2 [|b|]); auto with zarith.
- match goal with |- context[ww_compare ?x ?y] =>
- change (ww_compare x y) with (DoubleBase.ww_compare w0 w_compare x y)
- end.
- rewrite (@spec_ww_compare w w0 w_digits w_to_Z w_compare
- ZnZ.spec_0 ZnZ.spec_to_Z ZnZ.spec_compare); case Zcompare_spec;
- intros H2;
- match goal with H: context[w_square_c] |- _ =>
- generalize H; clear H
- end; autorewrite with w_rewrite; try rewrite _w0_is_0; try rewrite !_w1_is_1; auto with zarith.
- unfold w_square_c, ww_to_Z, w_to_Z, w_digits; rewrite ZnZ.spec_square_c; auto with zarith.
- intros H2;rewrite H2; simpl.
- rewrite _w0_is_0; simpl.
- rewrite Z_mod_same; auto with zarith.
- generalize (high_zero (w_square_c w2)).
- unfold w_square_c; generalize (ZnZ.spec_square_c w2);
- case (ZnZ.square_c w2); simpl; auto with zarith.
- intros H3 _ _; rewrite <- H3; autorewrite with w_rewrite; auto.
- intros w4 w5.
- change (w_to_Z w0) with [|w0|]; rewrite _w0_is_0; simpl.
- change (w_to_Z w4) with [|w4|].
- change (w_to_Z w5) with [|w5|].
- intros H2 H3 H4.
- assert (E1: [|w4|] = 0).
- apply H3; auto with zarith.
- apply Zlt_trans with (1 := H4).
- case (ZnZ.spec_to_Z b); auto with zarith.
- generalize H4 H2; rewrite E1; rewrite Zmult_0_l; rewrite Zplus_0_l;
- clear H4 H2; intros H4 H2.
- rewrite <- H2; rewrite Zmod_small; auto with zarith.
- case (ZnZ.spec_to_Z w5); auto with zarith.
- intros H2.
- match goal with |- context[split ?x] =>
- generalize (split_correct x);
- case (split x); auto with zarith
- end.
- assert (F1: [[w_square_c w2]] < [|b|] * [|b|]).
- unfold w_square_c, ww_to_Z, w_digits, w_to_Z.
- rewrite ZnZ.spec_square_c; auto with zarith.
- apply Zmult_lt_compat; auto with zarith.
- case (ZnZ.spec_to_Z w2); auto with zarith.
- case (ZnZ.spec_to_Z w2); auto with zarith.
- intros w4 w5; rewrite ww_lsl_n_spec; auto with zarith.
- intros H3.
- unfold w_div21; match goal with |- context[ZnZ.div21 ?y ?z ?t] =>
- generalize (ZnZ.spec_div21 y z t);
- case (ZnZ.div21 y z t)
- end.
- rewrite b2n_spec; case (n_spec); auto.
- intros H4 H5 w6 w7 H6.
- case H6; auto with zarith.
- case (Zle_or_lt (2 ^ [|n|] * [|b|]) [|w4|]); auto; intros H7.
- match type of H3 with ?X = ?Y =>
- absurd (Y < X)
- end.
- apply Zle_not_lt; rewrite H3; auto with zarith.
- simpl ww_to_Z.
- match goal with |- ?X < ?Y + _ =>
- apply Zlt_le_trans with Y; auto with zarith
- end.
- apply Zlt_trans with (2 ^ [|n|] * ([|b|] * [|b|]));
- auto with zarith.
- apply Zmult_lt_compat_l; auto with zarith.
- rewrite Zmult_assoc.
- apply Zmult_lt_compat2; auto with zarith.
- case (ZnZ.spec_to_Z b); auto with zarith.
- unfold w_to_Z,w_digits;case (ZnZ.spec_to_Z w5); auto with zarith.
- clear H6; intros H7 H8.
- rewrite w_lsr_n_spec; auto with zarith.
- rewrite <- (Z_div_mult ([|w2|] * [|w2|]) (2 ^ [|n|]));
- auto with zarith; rewrite Zmult_comm.
- rewrite <- ZnZ.spec_square_c; auto with zarith.
- unfold w_square_c, ww_to_Z in H3; unfold w_digits,w_to_Z in H3.
- rewrite <- H3; simpl.
- rewrite H7; rewrite (fun x => Zmult_comm (2 ^ x));
- rewrite Zmult_assoc; rewrite BigNumPrelude.Z_div_plus_l; auto with zarith.
- rewrite Zplus_mod; auto with zarith.
- rewrite Z_mod_mult; auto with zarith.
- rewrite Zplus_0_l; auto with zarith.
- rewrite Zmod_mod; auto with zarith.
- rewrite Zmod_small; auto with zarith.
- split; auto with zarith.
- apply Zdiv_lt_upper_bound; auto with zarith.
- rewrite Zmult_comm; auto with zarith.
- Qed.
-
- Let _power_mod :=
- fix pow_mod (x:w) (p:positive) {struct p} : w :=
- match p with
- | xH => x
- | xO p' =>
- let pow := pow_mod x p' in
- _square_mod pow
- | xI p' =>
- let pow := pow_mod x p' in
- _mul_mod (_square_mod pow) x
- end.
-
- Lemma _power_mod_spec: forall w t p, [|w|] = t mod [|b|] ->
- [|_power_mod w p|] = (Zpower_pos [|w|] p) mod [|b|].
- intros w2 t p; elim p; simpl; auto with zarith.
- intros p' Rec H.
- assert (F: [|w2|] < [|b|]).
- case (Z_mod_lt t [|b|]); auto with zarith.
- replace (xI p') with (p' + p' + 1)%positive.
- repeat rewrite Zpower_pos_is_exp; auto with zarith.
- pose (t1 := [|_power_mod w2 p'|]).
- rewrite _mul_mod_spec with (t1 := t1 * t1)
- (t2 := t); auto with zarith.
- rewrite _square_mod_spec with (t := Zpower_pos [|w2|] p'); auto with zarith.
- rewrite Rec; auto with zarith.
- assert (tmp: forall p, Zpower_pos p 1 = p); try (rewrite tmp; clear tmp).
- intros p1; unfold Zpower_pos; simpl; ring.
- rewrite <- Zmult_mod; auto with zarith.
- rewrite Zmult_mod; auto with zarith.
- rewrite Zmod_mod; auto with zarith.
- rewrite <- Zmult_mod; auto with zarith.
- simpl; unfold t1; apply _square_mod_spec with (t := Zpower_pos [|w2|] p'); auto with zarith.
- rewrite xI_succ_xO; rewrite <- Pplus_diag.
- rewrite Pplus_one_succ_r; auto.
- intros p' Rec H.
- replace (xO p') with (p' + p')%positive.
- repeat rewrite Zpower_pos_is_exp; auto with zarith.
- rewrite _square_mod_spec with (t := Zpower_pos [|w2|] p'); auto with zarith.
- rewrite Rec; auto with zarith.
- rewrite <- Zmult_mod; auto with zarith.
- rewrite <- Pplus_diag; auto.
- intros H.
- assert (tmp: forall p, Zpower_pos p 1 = p); try (rewrite tmp; clear tmp).
- intros p1; unfold Zpower_pos; simpl; ring.
- rewrite Zmod_small; auto with zarith.
- assert (F: [|w2|] < [|b|]).
- case (Z_mod_lt t [|b|]); auto with zarith.
- case (ZnZ.spec_to_Z w2); auto with zarith.
- Qed.
-
- Definition make_mod_op :=
- mk_mod_op
- _succ_mod _add_mod
- _pred_mod _sub_mod
- _mul_mod _square_mod _power_mod.
-
- Definition make_mod_spec: mod_spec make_mod_op.
- apply mk_mod_spec.
- exact _succ_mod_spec.
- exact _add_mod_spec.
- exact _pred_mod_spec.
- exact _sub_mod_spec.
- exact _mul_mod_spec.
- exact _square_mod_spec.
- exact _power_mod_spec.
- Defined.
-
-(*********** Mersenne special **********)
-
- Variable p: positive.
- Variable zp: w.
-
- Hypothesis zp_b: [|zp|] = Zpos p.
- Hypothesis p_lt_w_digits: Zpos p <= Zpos w_digits.
-
- Let p1 := Pminus (xO w_digits) p.
-
- Theorem p_p1: Zpos p + Zpos p1 = Zpos (xO w_digits).
- unfold p1.
- rewrite Zpos_minus; auto with zarith.
- rewrite Zmax_right; auto with zarith.
- rewrite Zpos_xO; auto with zarith.
- assert (0 < Zpos w_digits); auto with zarith.
- Qed.
-
- Let zp1 := ww_sub ww_zdigits (WW w0 zp).
-
- Let spec_add2: forall x y,
- [[w_add2 x y]] = [|x|] + [|y|].
- unfold w_add2.
- intros xh xl; generalize (ZnZ.spec_add_c xh xl).
- unfold w_add_c; case ZnZ.add_c; unfold interp_carry; simpl ww_to_Z.
- intros w2 Hw2; simpl; unfold w_to_Z; rewrite Hw2.
- unfold w0; rewrite ZnZ.spec_0; simpl; auto with zarith.
- intros w2; rewrite Zmult_1_l; simpl.
- unfold w_to_Z, w1; rewrite ZnZ.spec_1; auto with zarith.
- rewrite Zmult_1_l; auto.
- Qed.
-
- Let spec_ww_digits:
- [[ww_zdigits]] = Zpos (xO w_digits).
- Proof.
- unfold w_to_Z, ww_zdigits.
- rewrite spec_add2.
- unfold w_to_Z, w_zdigits, w_digits.
- rewrite ZnZ.spec_zdigits; auto.
- rewrite Zpos_xO; auto with zarith.
- Qed.
-
- Let spec_ww_to_Z := (spec_ww_to_Z _ _ ZnZ.spec_to_Z).
- Let spec_ww_compare := spec_ww_compare _ _ _ _ ZnZ.spec_0
- ZnZ.spec_to_Z ZnZ.spec_compare.
- Let spec_ww_sub :=
- spec_ww_sub w0 zp wWW zp1 w_opp_c w_opp_carry
- w_sub_c w_opp w_sub w_sub_carry w_digits w_to_Z
- ZnZ.spec_0
- ZnZ.spec_to_Z
- ZnZ.spec_WW
- ZnZ.spec_opp_c
- ZnZ.spec_opp
- ZnZ.spec_opp_carry
- ZnZ.spec_sub_c
- ZnZ.spec_sub
- ZnZ.spec_sub_carry.
-
- Theorem zp1_b: [[zp1]] = Zpos p1.
- change ([[DoubleSub.ww_sub w0 wWW w_opp_c w_opp_carry w_sub_c w_opp w_sub
- w_sub_carry ww_zdigits (WW w0 zp)]] =
- Zpos p1).
- rewrite spec_ww_sub; auto with zarith.
- rewrite spec_ww_digits; simpl ww_to_Z.
- change (w_to_Z w0) with [|w0|].
- unfold w0; rewrite ZnZ.spec_0; autorewrite with rm10; auto.
- change (w_to_Z zp) with [|zp|].
- rewrite zp_b.
- rewrite Zmod_small; auto with zarith.
- rewrite <- p_p1; auto with zarith.
- unfold ww_digits; split; auto with zarith.
- rewrite <- p_p1; auto with zarith.
- assert (0 < Zpos p1); auto with zarith.
- apply Zle_lt_trans with (Zpos (xO w_digits)); auto with zarith.
- assert (0 < Zpos p); auto with zarith.
- unfold base; apply Zpower2_lt_lin; auto with zarith.
- Qed.
-
- Hypothesis p_b: [|b|] = 2 ^ (Zpos p) - 1.
-
-
- Let w_pos_mod := ZnZ.pos_mod.
-
- Let add_mul_div :=
- DoubleLift.ww_add_mul_div w0 wWW wW0 w0W
- ww_compare w_add_mul_div
- ww_sub w_zdigits low.
-
- Let _mmul_mod x y :=
- let xy := w_mul_c x y in
- match xy with
- W0 => w0
- | WW xh xl =>
- let xl1 := w_pos_mod zp xl in
- match add_mul_div zp1 W0 xy with
- W0 => match w_compare xl1 b with
- | Lt => xl1
- | Eq => w0
- | Gt => w1
- end
- | WW _ xl2 => _add_mod xl1 xl2
- end
- end.
-
- Hint Unfold w_digits.
-
- Lemma WW_0: forall x y, [[WW x y]] = 0 -> [|x|] = 0 /\ [|y|] =0.
- intros x y; simpl; case (ZnZ.spec_to_Z x); intros H1 H2;
- case (ZnZ.spec_to_Z y); intros H3 H4 H5.
- case Zle_lt_or_eq with (1 := H1); clear H1; intros H1; auto with zarith.
- absurd (0 < [|x|] * base (ZnZ.digits w_op) + [|y|]); auto with zarith.
- unfold w_to_Z, w_digits in H5;auto with zarith.
- match goal with |- _ < ?X + _ =>
- apply Zlt_le_trans with X; auto with zarith
- end.
- case Zle_lt_or_eq with (1 := H3); clear H3; intros H3; auto with zarith.
- absurd (0 < [|x|] * base (ZnZ.digits w_op) + [|y|]); auto with zarith.
- unfold w_to_Z, w_digits in H5;auto with zarith.
- rewrite <- H1; rewrite Zmult_0_l; auto with zarith.
- Qed.
-
- Theorem WW0_is_0: [[W0]] = 0.
- simpl; auto.
- Qed.
- Hint Rewrite WW0_is_0: w_rewrite.
-
- Theorem mmul_aux0: Zpos (xO w_digits) - Zpos p1 = Zpos p.
- unfold w_digits.
- apply trans_equal with (Zpos p + Zpos p1 - Zpos p1); auto with zarith.
- rewrite p_p1; auto with zarith.
- Qed.
-
- Theorem mmul_aux1: 2 ^ Zpos w_digits =
- 2 ^ (Zpos w_digits - Zpos p) * 2 ^ Zpos p.
- rewrite <- Zpower_exp; auto with zarith.
- eq_tac; auto with zarith.
- Qed.
-
- Theorem mmul_aux2:forall x,
- x mod (2 ^ Zpos p - 1) =
- ((x / 2 ^ Zpos p) + (x mod 2 ^ Zpos p)) mod (2 ^ Zpos p - 1).
- intros x; pattern x at 1; rewrite Z_div_mod_eq with (b := 2 ^ Zpos p); auto with zarith.
- match goal with |- (?X * ?Y + ?Z) mod (?X - 1) = ?T =>
- replace (X * Y + Z) with (Y * (X - 1) + (Y + Z)); try ring
- end.
- rewrite Zplus_mod; auto with zarith.
- rewrite Z_mod_mult; auto with zarith.
- rewrite Zplus_0_l.
- rewrite Zmod_mod; auto with zarith.
- Qed.
-
- Theorem mmul_aux3:forall xh xl,
- [[WW xh xl]] mod (2 ^ Zpos p) = [|xl|] mod (2 ^ Zpos p).
- intros xh xl; simpl ww_to_Z; unfold base.
- rewrite Zplus_mod; auto with zarith.
- generalize mmul_aux1; unfold w_digits; intros tmp; rewrite tmp;
- clear tmp.
- rewrite Zmult_assoc.
- rewrite Z_mod_mult; auto with zarith.
- rewrite Zplus_0_l; apply Zmod_mod; auto with zarith.
- Qed.
-
- Let spec_low: forall x,
- [|low x|] = [[x]] mod base w_digits.
- intros x; case x; simpl low; auto with zarith.
- intros xh xl; simpl.
- rewrite Zplus_comm; rewrite Z_mod_plus; auto with zarith.
- rewrite Zmod_small; auto with zarith.
- case (ZnZ.spec_to_Z xl); auto with zarith.
- unfold base; auto with zarith.
- Qed.
-
- Theorem mmul_aux4:forall x,
- [[x]] < [|b|] * 2 ^ Zpos p ->
- match add_mul_div zp1 W0 x with
- W0 => 0
- | WW _ xl2 => [|xl2|]
- end = [[x]] / 2 ^ Zpos p.
- intros x Hx.
- assert (Hp: [[zp1]] <= Zpos (xO w_digits)); auto with zarith.
- rewrite zp1_b; rewrite <- p_p1; auto with zarith.
- assert (0 <= Zpos p); auto with zarith.
- generalize (@DoubleLift.spec_ww_add_mul_div w w0 wWW wW0 w0W
- ww_compare w_add_mul_div ww_sub w_digits w_zdigits low w_to_Z
- ZnZ.spec_0 ZnZ.spec_to_Z spec_ww_to_Z
- ZnZ.spec_WW ZnZ.spec_WO ZnZ.spec_OW
- spec_ww_compare ZnZ.spec_add_mul_div spec_ww_sub
- ZnZ.spec_zdigits spec_low W0 x zp1 Hp).
- unfold add_mul_div;
- case DoubleLift.ww_add_mul_div; autorewrite with w_rewrite; auto.
- rewrite Zmult_0_l; rewrite Zplus_0_l.
- rewrite zp1_b.
- generalize mmul_aux0; unfold w_digits; intros tmp; rewrite tmp.
- rewrite Zmod_small; auto with zarith.
- split; auto with zarith.
- apply Z_div_pos; auto with zarith.
- case (spec_ww_to_Z x); auto with zarith.
- unfold base.
- apply Zdiv_lt_upper_bound; auto with zarith.
- rewrite <- Zpower_exp; auto with zarith.
- apply Zlt_le_trans with (base (ww_digits (ZnZ.digits w_op))); auto with zarith.
- case (spec_ww_to_Z x); auto with zarith.
- unfold base; apply Zpower_le_monotone; auto with zarith.
- split; auto with zarith.
- assert (0 < Zpos p); auto with zarith.
- intros w2 w3; rewrite Zmult_0_l; rewrite Zplus_0_l.
- rewrite zp1_b.
- generalize mmul_aux0; unfold w_digits; intros tmp; rewrite tmp;
- clear tmp.
- simpl ww_to_Z; rewrite Zmod_small; auto with zarith.
- intros H1;
- generalize (high_zero (WW w2 w3)); unfold w_digits;intros tmp;
- simpl fst in tmp; simpl ww_to_Z in tmp;auto with zarith.
- unfold w_to_Z in *.
- rewrite tmp in H1; auto with zarith. clear tmp.
- simpl ww_to_Z; rewrite H1; apply Zdiv_lt_upper_bound; auto with zarith.
- unfold base; rewrite <- Zpower_exp; auto with zarith.
- apply Zlt_le_trans with (1 := Hx).
- apply Zle_trans with (2 ^ Zpos p * 2 ^ Zpos p).
- rewrite p_b; apply Zmult_le_compat_r; auto with zarith.
- rewrite <- Zpower_exp; auto with zarith.
- apply Zpower_le_monotone; auto with zarith.
- split; auto with zarith.
- apply Z_div_pos; auto with zarith.
- case (spec_ww_to_Z x); auto with zarith.
- unfold base.
- apply Zdiv_lt_upper_bound; auto with zarith.
- rewrite <- Zpower_exp; auto with zarith.
- apply Zlt_le_trans with (base (ww_digits (ZnZ.digits w_op))); auto with zarith.
- case (spec_ww_to_Z x); auto with zarith.
- unfold base; apply Zpower_le_monotone; auto with zarith.
- split; auto with zarith.
- assert (0 < Zpos p); auto with zarith.
- Qed.
-
- Theorem mmul_aux5:forall xh xl,
- [[WW xh xl]] < [|b|] * 2 ^ Zpos p ->
- let xl1 := w_pos_mod zp xl in
- let r :=
- match add_mul_div zp1 W0 (WW xh xl) with
- W0 => match w_compare xl1 b with
- | Lt => xl1
- | Eq => w0
- | Gt => w1
- end
- | WW _ xl2 => _add_mod xl1 xl2
- end in
- [|r|] = [[WW xh xl]] mod [|b|].
- intros xh xl Hx xl1 r; unfold r; clear r.
- generalize (mmul_aux4 _ Hx).
- simpl ww_to_Z; rewrite p_b.
- rewrite mmul_aux2.
- assert (Hp: [[zp1]] <= Zpos (xO w_digits)); auto with zarith.
- rewrite zp1_b; rewrite <- p_p1; auto with zarith.
- assert (0 <= Zpos p); auto with zarith.
- generalize (@DoubleLift.spec_ww_add_mul_div w w0 wWW wW0 w0W
- ww_compare w_add_mul_div ww_sub w_digits w_zdigits low w_to_Z
- ZnZ.spec_0 ZnZ.spec_to_Z spec_ww_to_Z
- ZnZ.spec_WW ZnZ.spec_WO ZnZ.spec_OW
- spec_ww_compare ZnZ.spec_add_mul_div spec_ww_sub
- ZnZ.spec_zdigits spec_low W0 (WW xh xl) zp1 Hp).
- unfold add_mul_div;
- case DoubleLift.ww_add_mul_div; autorewrite with w_rewrite; auto.
- rewrite Zmult_0_l; rewrite Zplus_0_l.
- rewrite zp1_b.
- generalize mmul_aux0; unfold w_digits; intros tmp; rewrite tmp; clear tmp.
- intros H1 H2.
- rewrite <- H2.
- rewrite Zplus_0_l.
- generalize mmul_aux3; simpl ww_to_Z; intros tmp; rewrite tmp; clear tmp;
- auto with zarith.
- unfold xl1; unfold w_pos_mod.
- rewrite <- p_b; rewrite <- zp_b.
- rewrite <- ZnZ.spec_pos_mod; auto with zarith.
- unfold w_compare; rewrite ZnZ.spec_compare;
- case Zcompare_spec; intros Hc;
- match goal with H: context[b] |- _ =>
- generalize H; clear H
- end; try rewrite _w0_is_0.
- intros H3; rewrite H3.
- rewrite Z_mod_same; auto with zarith.
- intros H3; rewrite Zmod_small; auto with zarith.
- case (ZnZ.spec_to_Z (ZnZ.pos_mod zp xl)); unfold w_to_Z; auto with zarith.
- rewrite p_b; rewrite ZnZ.spec_pos_mod; auto with zarith.
- intros H3; assert (HH: [|xl|] mod 2 ^ Zpos p = 2 ^ Zpos p).
- apply Zle_antisym; auto with zarith.
- case (Z_mod_lt ([|xl|]) (2 ^ Zpos p)); auto with zarith.
- rewrite zp_b in H3; auto with zarith.
- rewrite zp_b; rewrite HH.
- rewrite <- Zmod_minus_one; auto with zarith.
- rewrite _w1_is_1; rewrite Zmod_small; auto with zarith.
- rewrite Zmult_0_l; rewrite Zplus_0_l.
- rewrite zp1_b.
- generalize mmul_aux0; unfold w_digits; intros tmp; rewrite tmp; clear tmp.
- intros w2 w3 H1 H2; rewrite <- H2.
- generalize mmul_aux3; simpl ww_to_Z; intros tmp; rewrite tmp; clear tmp;
- auto with zarith.
- rewrite <- p_b; rewrite <- zp_b.
- rewrite <- ZnZ.spec_pos_mod; auto with zarith.
- unfold xl1; unfold w_pos_mod.
- rewrite Zplus_comm.
- apply _add_mod_correct; auto with zarith.
- assert (tmp: forall x, 2 * x = x + x); auto with zarith;
- rewrite tmp; apply Zplus_le_lt_compat; clear tmp; auto with zarith.
- rewrite ZnZ.spec_pos_mod; auto with zarith.
- rewrite p_b; case (Z_mod_lt [|xl|] (2 ^ Zpos p)); auto with zarith.
- rewrite zp_b; auto with zarith.
- rewrite H2; apply Zdiv_lt_upper_bound; auto with zarith.
- Qed.
-
- Lemma _mmul_mod_spec: forall w1 w2 t1 t2, [|w1|] = t1 mod [|b|] -> [|w2|] = t2 mod [|b|] ->
- [|_mmul_mod w1 w2|] = ([|w1|] * [|w2|]) mod [|b|].
- intros w2 w3 t1 t2; unfold _mmul_mod, w_mul_c; intros H H1.
- assert (F: [|w2|] < [|b|]).
- case (Z_mod_lt t1 [|b|]); auto with zarith.
- assert (F': [|w3|] < [|b|]).
- case (Z_mod_lt t2 [|b|]); auto with zarith.
- match goal with |- context[ZnZ.mul_c ?x ?y] =>
- generalize (ZnZ.spec_mul_c x y); unfold interp_carry;
- case (ZnZ.mul_c x y); autorewrite with w_rewrite
- end; auto with zarith.
- simpl; intros H2; rewrite <- H2; rewrite Zmod_small;
- auto with zarith.
- intros w4 w5 H2.
- rewrite mmul_aux5; auto with zarith.
- rewrite <- H2; auto.
- unfold ww_to_Z,w_digits,w_to_Z; rewrite H2.
- apply Zmult_lt_compat; auto with zarith.
- case (ZnZ.spec_to_Z w2); auto with zarith.
- case (ZnZ.spec_to_Z w3); auto with zarith.
- Qed.
-
- Let _msquare_mod x :=
- let xy := w_square_c x in
- match xy with
- W0 => w0
- | WW xh xl =>
- let xl1 := w_pos_mod zp xl in
- match add_mul_div zp1 W0 xy with
- W0 => match w_compare xl1 b with
- | Lt => xl1
- | Eq => w0
- | Gt => w1
- end
- | WW _ xl2 => _add_mod xl1 xl2
- end
- end.
-
- Lemma _msquare_mod_spec: forall w1 t1, [|w1|] = t1 mod [|b|] ->
- [|_msquare_mod w1|] = ([|w1|] * [|w1|]) mod [|b|].
- intros w2 t2; unfold _msquare_mod, w_square_c; intros H.
- assert (F: [|w2|] < [|b|]).
- case (Z_mod_lt t2 [|b|]); auto with zarith.
- match goal with |- context[ZnZ.square_c ?x] =>
- generalize (ZnZ.spec_square_c x); unfold interp_carry;
- case (ZnZ.square_c x); autorewrite with w_rewrite
- end; auto with zarith.
- simpl; intros H2; rewrite <- H2; rewrite Zmod_small;
- auto with zarith.
- intros w4 w5 H2.
- rewrite mmul_aux5; auto with zarith.
- unfold ww_to_Z, w_to_Z ,w_digits; rewrite <- H2; auto.
- unfold ww_to_Z,w_to_Z ,w_digits; rewrite H2.
- apply Zmult_lt_compat; auto with zarith.
- case (ZnZ.spec_to_Z w2); auto with zarith.
- case (ZnZ.spec_to_Z w2); auto with zarith.
- Qed.
-
- Definition mmake_mod_op :=
- mk_mod_op
- _succ_mod _add_mod
- _pred_mod _sub_mod
- _mmul_mod _msquare_mod _power_mod.
-
- Definition mmake_mod_spec: mod_spec mmake_mod_op.
- apply mk_mod_spec.
- exact _succ_mod_spec.
- exact _add_mod_spec.
- exact _pred_mod_spec.
- exact _sub_mod_spec.
- exact _mmul_mod_spec.
- exact _msquare_mod_spec.
- exact _power_mod_spec.
- Defined.
-
-End Mod_op.
-