freescale porting, work in progress

[helm.git] / helm / software / matita / contribs / ng_assembly / num / byte8_lemmas.ma

diff --git a/helm/software/matita/contribs/ng_assembly/num/byte8_lemmas.ma b/helm/software/matita/contribs/ng_assembly/num/byte8_lemmas.ma
index 1d32793cc3e1b724048df8598278c2572fe18047..c71eed49b0d04b0c544878cc749bf9e4f5db5a4e 100755 (executable)
--- a/helm/software/matita/contribs/ng_assembly/num/byte8_lemmas.ma
+++ b/helm/software/matita/contribs/ng_assembly/num/byte8_lemmas.ma
@@ -286,3 +286,69 @@ nlemma eq_to_eqb8 : ∀b1,b2.b1 = b2 → eq_b8 b1 b2 = true.
  nnormalize;
  napply refl_eq.
 nqed.
+
+nlemma decidable_b8_aux1 : ∀e1,e2,e3,e4.e1 ≠ e3 → 〈e1,e2〉 ≠ 〈e3,e4〉.
+ #e1; #e2; #e3; #e4;
+ nnormalize; #H; #H1;
+ napply (H (byte8_destruct_1 … H1)).
+nqed.
+
+nlemma decidable_b8_aux2 : ∀e1,e2,e3,e4.e2 ≠ e4 → 〈e1,e2〉 ≠ 〈e3,e4〉.
+ #e1; #e2; #e3; #e4;
+ nnormalize; #H; #H1;
+ napply (H (byte8_destruct_2 … H1)).
+nqed.
+
+nlemma decidable_b8 : ∀x,y:byte8.decidable (x = y).
+ #x; nelim x; #e1; #e2;
+ #y; nelim y; #e3; #e4;
+ nnormalize;
+ napply (or_elim (e1 = e3) (e1 ≠ e3) ? (decidable_ex e1 e3) …);
+ ##[ ##2: #H; napply (or_intror … (decidable_b8_aux1 e1 e2 e3 e4 H))
+ ##| ##1: #H; napply (or_elim (e2 = e4) (e2 ≠ e4) ? (decidable_ex e2 e4) …);
+          ##[ ##2: #H1; napply (or_intror … (decidable_b8_aux2 e1 e2 e3 e4 H1))
+          ##| ##1: #H1; nrewrite > H; nrewrite > H1;
+                        napply (or_introl … (refl_eq ? 〈e3,e4〉))
+          ##]
+ ##]
+nqed.
+
+nlemma neqb8_to_neq : ∀b1,b2:byte8.(eq_b8 b1 b2 = false) → (b1 ≠ b2).
+ #b1; #b2;
+ nelim b1;
+ nelim b2;
+ #e1; #e2; #e3; #e4;
+ nchange with ((((eq_ex e3 e1) ⊗ (eq_ex e4 e2)) = false) → ?);
+ #H;
+ napply (or_elim ((eq_ex e3 e1) = false) ((eq_ex e4 e2) = false) ? (andb_false … H) …);
+ ##[ ##1: #H1; napply (decidable_b8_aux1 … (neqex_to_neq … H1))
+ ##| ##2: #H1; napply (decidable_b8_aux2 … (neqex_to_neq … H1))
+ ##]
+nqed.
+
+nlemma byte8_destruct : ∀e1,e2,e3,e4.〈e1,e2〉 ≠ 〈e3,e4〉 → e1 ≠ e3 ∨ e2 ≠ e4.
+ #e1; #e2; #e3; #e4;
+ nnormalize; #H;
+ napply (or_elim (e1 = e3) (e1 ≠ e3) ? (decidable_ex e1 e3) …);
+ ##[ ##2: #H1; napply (or_introl … H1)
+ ##| ##1: #H1; napply (or_elim (e2 = e4) (e2 ≠ e4) ? (decidable_ex e2 e4) …);
+          ##[ ##2: #H2; napply (or_intror … H2)
+          ##| ##1: #H2; nrewrite > H1 in H:(%);
+                   nrewrite > H2;
+                   #H; nelim (H (refl_eq …))
+          ##]
+ ##]
+nqed.
+
+nlemma neq_to_neqb8 : ∀b1,b2.b1 ≠ b2 → eq_b8 b1 b2 = false.
+ #b1; #b2;
+ nelim b1; #e1; #e2;
+ nelim b2; #e3; #e4;
+ #H; nchange with (((eq_ex e1 e3) ⊗ (eq_ex e2 e4)) = false);
+ napply (or_elim (e1 ≠ e3) (e2 ≠ e4) ? (byte8_destruct … H) …);
+ ##[ ##1: #H1; nrewrite > (neq_to_neqex … H1); nnormalize; napply refl_eq
+ ##| ##2: #H1; nrewrite > (neq_to_neqex … H1);
+          nrewrite > (symmetric_andbool (eq_ex e1 e3) false);
+          nnormalize; napply refl_eq
+ ##]
+nqed.