diff --git a/src/HOL/Bit_Operations.thy b/src/HOL/Bit_Operations.thy
--- a/src/HOL/Bit_Operations.thy
+++ b/src/HOL/Bit_Operations.thy
@@ -1,3861 +1,3836 @@
 (*  Author:  Florian Haftmann, TUM
 *)
 
 section \<open>Bit operations in suitable algebraic structures\<close>
 
 theory Bit_Operations
   imports Presburger Groups_List
 begin
 
 subsection \<open>Abstract bit structures\<close>
 
 class semiring_bits = semiring_parity +
   assumes bits_induct [case_names stable rec]:
     \<open>(\<And>a. a div 2 = a \<Longrightarrow> P a)
      \<Longrightarrow> (\<And>a b. P a \<Longrightarrow> (of_bool b + 2 * a) div 2 = a \<Longrightarrow> P (of_bool b + 2 * a))
         \<Longrightarrow> P a\<close>
   assumes bits_div_0 [simp]: \<open>0 div a = 0\<close>
     and bits_div_by_1 [simp]: \<open>a div 1 = a\<close>
     and bits_mod_div_trivial [simp]: \<open>a mod b div b = 0\<close>
     and even_succ_div_2 [simp]: \<open>even a \<Longrightarrow> (1 + a) div 2 = a div 2\<close>
     and even_mask_div_iff: \<open>even ((2 ^ m - 1) div 2 ^ n) \<longleftrightarrow> 2 ^ n = 0 \<or> m \<le> n\<close>
     and exp_div_exp_eq: \<open>2 ^ m div 2 ^ n = of_bool (2 ^ m \<noteq> 0 \<and> m \<ge> n) * 2 ^ (m - n)\<close>
     and div_exp_eq: \<open>a div 2 ^ m div 2 ^ n = a div 2 ^ (m + n)\<close>
     and mod_exp_eq: \<open>a mod 2 ^ m mod 2 ^ n = a mod 2 ^ min m n\<close>
     and mult_exp_mod_exp_eq: \<open>m \<le> n \<Longrightarrow> (a * 2 ^ m) mod (2 ^ n) = (a mod 2 ^ (n - m)) * 2 ^ m\<close>
     and div_exp_mod_exp_eq: \<open>a div 2 ^ n mod 2 ^ m = a mod (2 ^ (n + m)) div 2 ^ n\<close>
     and even_mult_exp_div_exp_iff: \<open>even (a * 2 ^ m div 2 ^ n) \<longleftrightarrow> m > n \<or> 2 ^ n = 0 \<or> (m \<le> n \<and> even (a div 2 ^ (n - m)))\<close>
   fixes bit :: \<open>'a \<Rightarrow> nat \<Rightarrow> bool\<close>
   assumes bit_iff_odd: \<open>bit a n \<longleftrightarrow> odd (a div 2 ^ n)\<close>
 begin
 
 text \<open>
   Having \<^const>\<open>bit\<close> as definitional class operation
   takes into account that specific instances can be implemented
   differently wrt. code generation.
 \<close>
 
 lemma bits_div_by_0 [simp]:
   \<open>a div 0 = 0\<close>
   by (metis add_cancel_right_right bits_mod_div_trivial mod_mult_div_eq mult_not_zero)
 
 lemma bits_1_div_2 [simp]:
   \<open>1 div 2 = 0\<close>
   using even_succ_div_2 [of 0] by simp
 
 lemma bits_1_div_exp [simp]:
   \<open>1 div 2 ^ n = of_bool (n = 0)\<close>
   using div_exp_eq [of 1 1] by (cases n) simp_all
 
 lemma even_succ_div_exp [simp]:
   \<open>(1 + a) div 2 ^ n = a div 2 ^ n\<close> if \<open>even a\<close> and \<open>n > 0\<close>
 proof (cases n)
   case 0
   with that show ?thesis
     by simp
 next
   case (Suc n)
   with \<open>even a\<close> have \<open>(1 + a) div 2 ^ Suc n = a div 2 ^ Suc n\<close>
   proof (induction n)
     case 0
     then show ?case
       by simp
   next
     case (Suc n)
     then show ?case
       using div_exp_eq [of _ 1 \<open>Suc n\<close>, symmetric]
       by simp
   qed
   with Suc show ?thesis
     by simp
 qed
 
 lemma even_succ_mod_exp [simp]:
   \<open>(1 + a) mod 2 ^ n = 1 + (a mod 2 ^ n)\<close> if \<open>even a\<close> and \<open>n > 0\<close>
   using div_mult_mod_eq [of \<open>1 + a\<close> \<open>2 ^ n\<close>] div_mult_mod_eq [of a \<open>2 ^ n\<close>] that
   by simp (metis (full_types) add.left_commute add_left_imp_eq)
 
 lemma bits_mod_by_1 [simp]:
   \<open>a mod 1 = 0\<close>
   using div_mult_mod_eq [of a 1] by simp
 
 lemma bits_mod_0 [simp]:
   \<open>0 mod a = 0\<close>
   using div_mult_mod_eq [of 0 a] by simp
 
 lemma bits_one_mod_two_eq_one [simp]:
   \<open>1 mod 2 = 1\<close>
   by (simp add: mod2_eq_if)
 
 lemma bit_0:
   \<open>bit a 0 \<longleftrightarrow> odd a\<close>
   by (simp add: bit_iff_odd)
 
 lemma bit_Suc:
   \<open>bit a (Suc n) \<longleftrightarrow> bit (a div 2) n\<close>
   using div_exp_eq [of a 1 n] by (simp add: bit_iff_odd)
 
 lemma bit_rec:
   \<open>bit a n \<longleftrightarrow> (if n = 0 then odd a else bit (a div 2) (n - 1))\<close>
   by (cases n) (simp_all add: bit_Suc bit_0)
 
 lemma bit_0_eq [simp]:
   \<open>bit 0 = bot\<close>
   by (simp add: fun_eq_iff bit_iff_odd)
 
 context
   fixes a
   assumes stable: \<open>a div 2 = a\<close>
 begin
 
 lemma bits_stable_imp_add_self:
   \<open>a + a mod 2 = 0\<close>
 proof -
   have \<open>a div 2 * 2 + a mod 2 = a\<close>
     by (fact div_mult_mod_eq)
   then have \<open>a * 2 + a mod 2 = a\<close>
     by (simp add: stable)
   then show ?thesis
     by (simp add: mult_2_right ac_simps)
 qed
 
 lemma stable_imp_bit_iff_odd:
   \<open>bit a n \<longleftrightarrow> odd a\<close>
   by (induction n) (simp_all add: stable bit_Suc bit_0)
 
 end
 
 lemma bit_iff_idd_imp_stable:
   \<open>a div 2 = a\<close> if \<open>\<And>n. bit a n \<longleftrightarrow> odd a\<close>
 using that proof (induction a rule: bits_induct)
   case (stable a)
   then show ?case
     by simp
 next
   case (rec a b)
   from rec.prems [of 1] have [simp]: \<open>b = odd a\<close>
     by (simp add: rec.hyps bit_Suc bit_0)
   from rec.hyps have hyp: \<open>(of_bool (odd a) + 2 * a) div 2 = a\<close>
     by simp
   have \<open>bit a n \<longleftrightarrow> odd a\<close> for n
     using rec.prems [of \<open>Suc n\<close>] by (simp add: hyp bit_Suc)
   then have \<open>a div 2 = a\<close>
     by (rule rec.IH)
   then have \<open>of_bool (odd a) + 2 * a = 2 * (a div 2) + of_bool (odd a)\<close>
     by (simp add: ac_simps)
   also have \<open>\<dots> = a\<close>
     using mult_div_mod_eq [of 2 a]
     by (simp add: of_bool_odd_eq_mod_2)
   finally show ?case
     using \<open>a div 2 = a\<close> by (simp add: hyp)
 qed
 
 lemma exp_eq_0_imp_not_bit:
   \<open>\<not> bit a n\<close> if \<open>2 ^ n = 0\<close>
   using that by (simp add: bit_iff_odd)
 
 definition possible_bit :: \<open>'a itself \<Rightarrow> nat \<Rightarrow> bool\<close>
   where \<open>possible_bit TYPE('a) n \<longleftrightarrow> 2 ^ n \<noteq> 0\<close>
   \<comment> \<open>This auxiliary avoids non-termination with extensionality.\<close>
 
 lemma possible_bit_0 [simp]:
   \<open>possible_bit TYPE('a) 0\<close>
   by (simp add: possible_bit_def)
 
 lemma fold_possible_bit:
   \<open>2 ^ n = 0 \<longleftrightarrow> \<not> possible_bit TYPE('a) n\<close>
   by (simp add: possible_bit_def)
 
 lemma bit_imp_possible_bit:
   \<open>possible_bit TYPE('a) n\<close> if \<open>bit a n\<close>
   using that by (auto simp add: possible_bit_def exp_eq_0_imp_not_bit)
 
 lemma impossible_bit:
   \<open>\<not> bit a n\<close> if \<open>\<not> possible_bit TYPE('a) n\<close>
   using that by (blast dest: bit_imp_possible_bit)
 
 lemma possible_bit_less_imp:
   \<open>possible_bit TYPE('a) j\<close> if \<open>possible_bit TYPE('a) i\<close> \<open>j \<le> i\<close>
   using power_add [of 2 j \<open>i - j\<close>] that mult_not_zero [of \<open>2 ^ j\<close> \<open>2 ^ (i - j)\<close>]
   by (simp add: possible_bit_def)
 
 lemma possible_bit_min [simp]:
   \<open>possible_bit TYPE('a) (min i j) \<longleftrightarrow> possible_bit TYPE('a) i \<or> possible_bit TYPE('a) j\<close>
   by (auto simp add: min_def elim: possible_bit_less_imp)
 
 lemma bit_eqI:
   \<open>a = b\<close> if \<open>\<And>n. possible_bit TYPE('a) n \<Longrightarrow> bit a n \<longleftrightarrow> bit b n\<close>
 proof -
   have \<open>bit a n \<longleftrightarrow> bit b n\<close> for n
   proof (cases \<open>2 ^ n = 0\<close>)
     case True
     then show ?thesis
       by (simp add: exp_eq_0_imp_not_bit)
   next
     case False
     then show ?thesis
       by (rule that[unfolded possible_bit_def])
   qed
   then show ?thesis proof (induction a arbitrary: b rule: bits_induct)
     case (stable a)
     from stable(2) [of 0] have **: \<open>even b \<longleftrightarrow> even a\<close>
       by (simp add: bit_0)
     have \<open>b div 2 = b\<close>
     proof (rule bit_iff_idd_imp_stable)
       fix n
       from stable have *: \<open>bit b n \<longleftrightarrow> bit a n\<close>
         by simp
       also have \<open>bit a n \<longleftrightarrow> odd a\<close>
         using stable by (simp add: stable_imp_bit_iff_odd)
       finally show \<open>bit b n \<longleftrightarrow> odd b\<close>
         by (simp add: **)
     qed
     from ** have \<open>a mod 2 = b mod 2\<close>
       by (simp add: mod2_eq_if)
     then have \<open>a mod 2 + (a + b) = b mod 2 + (a + b)\<close>
       by simp
     then have \<open>a + a mod 2 + b = b + b mod 2 + a\<close>
       by (simp add: ac_simps)
     with \<open>a div 2 = a\<close> \<open>b div 2 = b\<close> show ?case
       by (simp add: bits_stable_imp_add_self)
   next
     case (rec a p)
     from rec.prems [of 0] have [simp]: \<open>p = odd b\<close>
       by (simp add: bit_0)
     from rec.hyps have \<open>bit a n \<longleftrightarrow> bit (b div 2) n\<close> for n
       using rec.prems [of \<open>Suc n\<close>] by (simp add: bit_Suc)
     then have \<open>a = b div 2\<close>
       by (rule rec.IH)
     then have \<open>2 * a = 2 * (b div 2)\<close>
       by simp
     then have \<open>b mod 2 + 2 * a = b mod 2 + 2 * (b div 2)\<close>
       by simp
     also have \<open>\<dots> = b\<close>
       by (fact mod_mult_div_eq)
     finally show ?case
       by (auto simp add: mod2_eq_if)
   qed
 qed
 
 lemma bit_eq_iff:
   \<open>a = b \<longleftrightarrow> (\<forall>n. possible_bit TYPE('a) n \<longrightarrow> bit a n \<longleftrightarrow> bit b n)\<close>
   by (auto intro: bit_eqI)
 
 named_theorems bit_simps \<open>Simplification rules for \<^const>\<open>bit\<close>\<close>
 
 lemma bit_exp_iff [bit_simps]:
   \<open>bit (2 ^ m) n \<longleftrightarrow> possible_bit TYPE('a) n \<and> m = n\<close>
   by (auto simp add: bit_iff_odd exp_div_exp_eq possible_bit_def)
 
 lemma bit_1_iff [bit_simps]:
   \<open>bit 1 n \<longleftrightarrow> n = 0\<close>
   using bit_exp_iff [of 0 n]
   by auto
 
 lemma bit_2_iff [bit_simps]:
   \<open>bit 2 n \<longleftrightarrow> possible_bit TYPE('a) 1 \<and> n = 1\<close>
   using bit_exp_iff [of 1 n] by auto
 
 lemma even_bit_succ_iff:
   \<open>bit (1 + a) n \<longleftrightarrow> bit a n \<or> n = 0\<close> if \<open>even a\<close>
   using that by (cases \<open>n = 0\<close>) (simp_all add: bit_iff_odd)
 
 lemma bit_double_iff [bit_simps]:
   \<open>bit (2 * a) n \<longleftrightarrow> bit a (n - 1) \<and> n \<noteq> 0 \<and> possible_bit TYPE('a) n\<close>
   using even_mult_exp_div_exp_iff [of a 1 n]
   by (cases n, auto simp add: bit_iff_odd ac_simps possible_bit_def)
 
 lemma odd_bit_iff_bit_pred:
   \<open>bit a n \<longleftrightarrow> bit (a - 1) n \<or> n = 0\<close> if \<open>odd a\<close>
 proof -
   from \<open>odd a\<close> obtain b where \<open>a = 2 * b + 1\<close> ..
   moreover have \<open>bit (2 * b) n \<or> n = 0 \<longleftrightarrow> bit (1 + 2 * b) n\<close>
     using even_bit_succ_iff by simp
   ultimately show ?thesis by (simp add: ac_simps)
 qed
 
 lemma bit_eq_rec:
   \<open>a = b \<longleftrightarrow> (even a \<longleftrightarrow> even b) \<and> a div 2 = b div 2\<close> (is \<open>?P = ?Q\<close>)
 proof
   assume ?P
   then show ?Q
     by simp
 next
   assume ?Q
   then have \<open>even a \<longleftrightarrow> even b\<close> and \<open>a div 2 = b div 2\<close>
     by simp_all
   show ?P
   proof (rule bit_eqI)
     fix n
     show \<open>bit a n \<longleftrightarrow> bit b n\<close>
     proof (cases n)
       case 0
       with \<open>even a \<longleftrightarrow> even b\<close> show ?thesis
         by (simp add: bit_0)
     next
       case (Suc n)
       moreover from \<open>a div 2 = b div 2\<close> have \<open>bit (a div 2) n = bit (b div 2) n\<close>
         by simp
       ultimately show ?thesis
         by (simp add: bit_Suc)
     qed
   qed
 qed
 
 lemma bit_mod_2_iff [simp]:
   \<open>bit (a mod 2) n \<longleftrightarrow> n = 0 \<and> odd a\<close>
   by (cases a rule: parity_cases) (simp_all add: bit_iff_odd)
 
 lemma bit_mask_sub_iff:
   \<open>bit (2 ^ m - 1) n \<longleftrightarrow> possible_bit TYPE('a) n \<and> n < m\<close>
   by (simp add: bit_iff_odd even_mask_div_iff not_le possible_bit_def)
 
 lemma exp_add_not_zero_imp:
   \<open>2 ^ m \<noteq> 0\<close> and \<open>2 ^ n \<noteq> 0\<close> if \<open>2 ^ (m + n) \<noteq> 0\<close>
 proof -
   have \<open>\<not> (2 ^ m = 0 \<or> 2 ^ n = 0)\<close>
   proof (rule notI)
     assume \<open>2 ^ m = 0 \<or> 2 ^ n = 0\<close>
     then have \<open>2 ^ (m + n) = 0\<close>
       by (rule disjE) (simp_all add: power_add)
     with that show False ..
   qed
   then show \<open>2 ^ m \<noteq> 0\<close> and \<open>2 ^ n \<noteq> 0\<close>
     by simp_all
 qed
 
 lemma bit_disjunctive_add_iff:
   \<open>bit (a + b) n \<longleftrightarrow> bit a n \<or> bit b n\<close>
   if \<open>\<And>n. \<not> bit a n \<or> \<not> bit b n\<close>
 proof (cases \<open>2 ^ n = 0\<close>)
   case True
   then show ?thesis
     by (simp add: exp_eq_0_imp_not_bit)
 next
   case False
   with that show ?thesis proof (induction n arbitrary: a b)
     case 0
     from "0.prems"(1) [of 0] show ?case
       by (auto simp add: bit_0)
   next
     case (Suc n)
     from Suc.prems(1) [of 0] have even: \<open>even a \<or> even b\<close>
       by (auto simp add: bit_0)
     have bit: \<open>\<not> bit (a div 2) n \<or> \<not> bit (b div 2) n\<close> for n
       using Suc.prems(1) [of \<open>Suc n\<close>] by (simp add: bit_Suc)
     from Suc.prems(2) have \<open>2 * 2 ^ n \<noteq> 0\<close> \<open>2 ^ n \<noteq> 0\<close>
       by (auto simp add: mult_2)
     have \<open>a + b = (a div 2 * 2 + a mod 2) + (b div 2 * 2 + b mod 2)\<close>
       using div_mult_mod_eq [of a 2] div_mult_mod_eq [of b 2] by simp
     also have \<open>\<dots> = of_bool (odd a \<or> odd b) + 2 * (a div 2 + b div 2)\<close>
       using even by (auto simp add: algebra_simps mod2_eq_if)
     finally have \<open>bit ((a + b) div 2) n \<longleftrightarrow> bit (a div 2 + b div 2) n\<close>
       using \<open>2 * 2 ^ n \<noteq> 0\<close> by simp (simp_all flip: bit_Suc add: bit_double_iff possible_bit_def)
     also have \<open>\<dots> \<longleftrightarrow> bit (a div 2) n \<or> bit (b div 2) n\<close>
       using bit \<open>2 ^ n \<noteq> 0\<close> by (rule Suc.IH)
     finally show ?case
       by (simp add: bit_Suc)
   qed
 qed
 
 lemma
   exp_add_not_zero_imp_left: \<open>2 ^ m \<noteq> 0\<close>
   and exp_add_not_zero_imp_right: \<open>2 ^ n \<noteq> 0\<close>
   if \<open>2 ^ (m + n) \<noteq> 0\<close>
 proof -
   have \<open>\<not> (2 ^ m = 0 \<or> 2 ^ n = 0)\<close>
   proof (rule notI)
     assume \<open>2 ^ m = 0 \<or> 2 ^ n = 0\<close>
     then have \<open>2 ^ (m + n) = 0\<close>
       by (rule disjE) (simp_all add: power_add)
     with that show False ..
   qed
   then show \<open>2 ^ m \<noteq> 0\<close> and \<open>2 ^ n \<noteq> 0\<close>
     by simp_all
 qed
 
 lemma exp_not_zero_imp_exp_diff_not_zero:
   \<open>2 ^ (n - m) \<noteq> 0\<close> if \<open>2 ^ n \<noteq> 0\<close>
 proof (cases \<open>m \<le> n\<close>)
   case True
   moreover define q where \<open>q = n - m\<close>
   ultimately have \<open>n = m + q\<close>
     by simp
   with that show ?thesis
     by (simp add: exp_add_not_zero_imp_right)
 next
   case False
   with that show ?thesis
     by simp
 qed
 
 lemma bit_of_bool_iff [bit_simps]:
   \<open>bit (of_bool b) n \<longleftrightarrow> b \<and> n = 0\<close>
   by (simp add: bit_1_iff)
 
 end
 
 lemma nat_bit_induct [case_names zero even odd]:
   \<open>P n\<close> if zero: \<open>P 0\<close>
     and even: \<open>\<And>n. P n \<Longrightarrow> n > 0 \<Longrightarrow> P (2 * n)\<close>
     and odd: \<open>\<And>n. P n \<Longrightarrow> P (Suc (2 * n))\<close>
 proof (induction n rule: less_induct)
   case (less n)
   show \<open>P n\<close>
   proof (cases \<open>n = 0\<close>)
     case True with zero show ?thesis by simp
   next
     case False
     with less have hyp: \<open>P (n div 2)\<close> by simp
     show ?thesis
     proof (cases \<open>even n\<close>)
       case True
       then have \<open>n \<noteq> 1\<close>
         by auto
       with \<open>n \<noteq> 0\<close> have \<open>n div 2 > 0\<close>
         by simp
       with \<open>even n\<close> hyp even [of \<open>n div 2\<close>] show ?thesis
         by simp
     next
       case False
       with hyp odd [of \<open>n div 2\<close>] show ?thesis
         by simp
     qed
   qed
 qed
 
 instantiation nat :: semiring_bits
 begin
 
 definition bit_nat :: \<open>nat \<Rightarrow> nat \<Rightarrow> bool\<close>
   where \<open>bit_nat m n \<longleftrightarrow> odd (m div 2 ^ n)\<close>
 
 instance
 proof
   show \<open>P n\<close> if stable: \<open>\<And>n. n div 2 = n \<Longrightarrow> P n\<close>
     and rec: \<open>\<And>n b. P n \<Longrightarrow> (of_bool b + 2 * n) div 2 = n \<Longrightarrow> P (of_bool b + 2 * n)\<close>
     for P and n :: nat
   proof (induction n rule: nat_bit_induct)
     case zero
     from stable [of 0] show ?case
       by simp
   next
     case (even n)
     with rec [of n False] show ?case
       by simp
   next
     case (odd n)
     with rec [of n True] show ?case
       by simp
   qed
   show \<open>q mod 2 ^ m mod 2 ^ n = q mod 2 ^ min m n\<close>
     for q m n :: nat
     apply (auto simp add: less_iff_Suc_add power_add mod_mod_cancel split: split_min_lin)
     apply (metis div_mult2_eq mod_div_trivial mod_eq_self_iff_div_eq_0 mod_mult_self2_is_0 power_commutes)
     done
   show \<open>(q * 2 ^ m) mod (2 ^ n) = (q mod 2 ^ (n - m)) * 2 ^ m\<close> if \<open>m \<le> n\<close>
     for q m n :: nat
     using that
     apply (auto simp add: mod_mod_cancel div_mult2_eq power_add mod_mult2_eq le_iff_add split: split_min_lin)
     done
   show \<open>even ((2 ^ m - (1::nat)) div 2 ^ n) \<longleftrightarrow> 2 ^ n = (0::nat) \<or> m \<le> n\<close>
     for m n :: nat
     using even_mask_div_iff' [where ?'a = nat, of m n] by simp
   show \<open>even (q * 2 ^ m div 2 ^ n) \<longleftrightarrow> n < m \<or> (2::nat) ^ n = 0 \<or> m \<le> n \<and> even (q div 2 ^ (n - m))\<close>
     for m n q r :: nat
     apply (auto simp add: not_less power_add ac_simps dest!: le_Suc_ex)
     apply (metis (full_types) dvd_mult dvd_mult_imp_div dvd_power_iff_le not_less not_less_eq order_refl power_Suc)
     done
 qed (auto simp add: div_mult2_eq mod_mult2_eq power_add power_diff bit_nat_def)
 
 end
 
 lemma possible_bit_nat [simp]:
   \<open>possible_bit TYPE(nat) n\<close>
   by (simp add: possible_bit_def)
 
 lemma not_bit_Suc_0_Suc [simp]:
   \<open>\<not> bit (Suc 0) (Suc n)\<close>
   by (simp add: bit_Suc)
 
 lemma not_bit_Suc_0_numeral [simp]:
   \<open>\<not> bit (Suc 0) (numeral n)\<close>
   by (simp add: numeral_eq_Suc)
 
 context semiring_bits
 begin
 
 lemma bit_of_nat_iff [bit_simps]:
   \<open>bit (of_nat m) n \<longleftrightarrow> possible_bit TYPE('a) n \<and> bit m n\<close>
 proof (cases \<open>(2::'a) ^ n = 0\<close>)
   case True
   then show ?thesis
     by (simp add: exp_eq_0_imp_not_bit possible_bit_def)
 next
   case False
   then have \<open>bit (of_nat m) n \<longleftrightarrow> bit m n\<close>
   proof (induction m arbitrary: n rule: nat_bit_induct)
     case zero
     then show ?case
       by simp
   next
     case (even m)
     then show ?case
       by (cases n)
         (auto simp add: bit_double_iff Bit_Operations.bit_double_iff possible_bit_def bit_0 dest: mult_not_zero)
   next
     case (odd m)
     then show ?case
       by (cases n)
         (auto simp add: bit_double_iff even_bit_succ_iff possible_bit_def
           Bit_Operations.bit_Suc Bit_Operations.bit_0 dest: mult_not_zero)
   qed
   with False show ?thesis
     by (simp add: possible_bit_def)
 qed
 
 end
 
 lemma int_bit_induct [case_names zero minus even odd]:
   \<open>P k\<close> if zero_int: \<open>P 0\<close>
     and minus_int: \<open>P (- 1)\<close>
     and even_int: \<open>\<And>k. P k \<Longrightarrow> k \<noteq> 0 \<Longrightarrow> P (k * 2)\<close>
     and odd_int: \<open>\<And>k. P k \<Longrightarrow> k \<noteq> - 1 \<Longrightarrow> P (1 + (k * 2))\<close> for k :: int
 proof (cases \<open>k \<ge> 0\<close>)
   case True
   define n where \<open>n = nat k\<close>
   with True have \<open>k = int n\<close>
     by simp
   then show \<open>P k\<close>
   proof (induction n arbitrary: k rule: nat_bit_induct)
     case zero
     then show ?case
       by (simp add: zero_int)
   next
     case (even n)
     have \<open>P (int n * 2)\<close>
       by (rule even_int) (use even in simp_all)
     with even show ?case
       by (simp add: ac_simps)
   next
     case (odd n)
     have \<open>P (1 + (int n * 2))\<close>
       by (rule odd_int) (use odd in simp_all)
     with odd show ?case
       by (simp add: ac_simps)
   qed
 next
   case False
   define n where \<open>n = nat (- k - 1)\<close>
   with False have \<open>k = - int n - 1\<close>
     by simp
   then show \<open>P k\<close>
   proof (induction n arbitrary: k rule: nat_bit_induct)
     case zero
     then show ?case
       by (simp add: minus_int)
   next
     case (even n)
     have \<open>P (1 + (- int (Suc n) * 2))\<close>
       by (rule odd_int) (use even in \<open>simp_all add: algebra_simps\<close>)
     also have \<open>\<dots> = - int (2 * n) - 1\<close>
       by (simp add: algebra_simps)
     finally show ?case
       using even.prems by simp
   next
     case (odd n)
     have \<open>P (- int (Suc n) * 2)\<close>
       by (rule even_int) (use odd in \<open>simp_all add: algebra_simps\<close>)
     also have \<open>\<dots> = - int (Suc (2 * n)) - 1\<close>
       by (simp add: algebra_simps)
     finally show ?case
       using odd.prems by simp
   qed
 qed
 
 instantiation int :: semiring_bits
 begin
 
 definition bit_int :: \<open>int \<Rightarrow> nat \<Rightarrow> bool\<close>
   where \<open>bit_int k n \<longleftrightarrow> odd (k div 2 ^ n)\<close>
 
 instance
 proof
   show \<open>P k\<close> if stable: \<open>\<And>k. k div 2 = k \<Longrightarrow> P k\<close>
     and rec: \<open>\<And>k b. P k \<Longrightarrow> (of_bool b + 2 * k) div 2 = k \<Longrightarrow> P (of_bool b + 2 * k)\<close>
     for P and k :: int
   proof (induction k rule: int_bit_induct)
     case zero
     from stable [of 0] show ?case
       by simp
   next
     case minus
     from stable [of \<open>- 1\<close>] show ?case
       by simp
   next
     case (even k)
     with rec [of k False] show ?case
       by (simp add: ac_simps)
   next
     case (odd k)
     with rec [of k True] show ?case
       by (simp add: ac_simps)
   qed
   show \<open>(2::int) ^ m div 2 ^ n = of_bool ((2::int) ^ m \<noteq> 0 \<and> n \<le> m) * 2 ^ (m - n)\<close>
     for m n :: nat
   proof (cases \<open>m < n\<close>)
     case True
     then have \<open>n = m + (n - m)\<close>
       by simp
     then have \<open>(2::int) ^ m div 2 ^ n = (2::int) ^ m div 2 ^ (m + (n - m))\<close>
       by simp
     also have \<open>\<dots> = (2::int) ^ m div (2 ^ m * 2 ^ (n - m))\<close>
       by (simp add: power_add)
     also have \<open>\<dots> = (2::int) ^ m div 2 ^ m div 2 ^ (n - m)\<close>
       by (simp add: zdiv_zmult2_eq)
     finally show ?thesis using \<open>m < n\<close> by simp
   next
     case False
     then show ?thesis
       by (simp add: power_diff)
   qed
   show \<open>k mod 2 ^ m mod 2 ^ n = k mod 2 ^ min m n\<close>
     for m n :: nat and k :: int
     using mod_exp_eq [of \<open>nat k\<close> m n]
     apply (auto simp add: mod_mod_cancel zdiv_zmult2_eq power_add zmod_zmult2_eq le_iff_add split: split_min_lin)
      apply (auto simp add: less_iff_Suc_add mod_mod_cancel power_add)
     apply (simp only: flip: mult.left_commute [of \<open>2 ^ m\<close>])
     apply (subst zmod_zmult2_eq) apply simp_all
     done
   show \<open>(k * 2 ^ m) mod (2 ^ n) = (k mod 2 ^ (n - m)) * 2 ^ m\<close>
     if \<open>m \<le> n\<close> for m n :: nat and k :: int
     using that
     apply (auto simp add: power_add zmod_zmult2_eq le_iff_add split: split_min_lin)
     done
   show \<open>even ((2 ^ m - (1::int)) div 2 ^ n) \<longleftrightarrow> 2 ^ n = (0::int) \<or> m \<le> n\<close>
     for m n :: nat
     using even_mask_div_iff' [where ?'a = int, of m n] by simp
   show \<open>even (k * 2 ^ m div 2 ^ n) \<longleftrightarrow> n < m \<or> (2::int) ^ n = 0 \<or> m \<le> n \<and> even (k div 2 ^ (n - m))\<close>
     for m n :: nat and k l :: int
     apply (auto simp add: not_less power_add ac_simps dest!: le_Suc_ex)
     apply (metis Suc_leI dvd_mult dvd_mult_imp_div dvd_power_le dvd_refl power.simps(2))
     done
 qed (auto simp add: zdiv_zmult2_eq zmod_zmult2_eq power_add power_diff not_le bit_int_def)
 
 end
 
 lemma possible_bit_int [simp]:
   \<open>possible_bit TYPE(int) n\<close>
   by (simp add: possible_bit_def)
 
 lemma bit_not_int_iff':
   \<open>bit (- k - 1) n \<longleftrightarrow> \<not> bit k n\<close> for k :: int
 proof (induction n arbitrary: k)
   case 0
   show ?case
     by (simp add: bit_0)
 next
   case (Suc n)
   have \<open>- k - 1 = - (k + 2) + 1\<close>
     by simp
   also have \<open>(- (k + 2) + 1) div 2 = - (k div 2) - 1\<close>
   proof (cases \<open>even k\<close>)
     case True
     then have \<open>- k div 2 = - (k div 2)\<close>
       by rule (simp flip: mult_minus_right)
     with True show ?thesis
       by simp
   next
     case False
     have \<open>4 = 2 * (2::int)\<close>
       by simp
     also have \<open>2 * 2 div 2 = (2::int)\<close>
       by (simp only: nonzero_mult_div_cancel_left)
     finally have *: \<open>4 div 2 = (2::int)\<close> .
     from False obtain l where k: \<open>k = 2 * l + 1\<close> ..
     then have \<open>- k - 2 = 2 * - (l + 2) + 1\<close>
       by simp
     then have \<open>(- k - 2) div 2 + 1 = - (k div 2) - 1\<close>
       by (simp flip: mult_minus_right add: *) (simp add: k)
     with False show ?thesis
       by simp
   qed
   finally have \<open>(- k - 1) div 2 = - (k div 2) - 1\<close> .
   with Suc show ?case
     by (simp add: bit_Suc)
 qed
 
 lemma bit_nat_iff [bit_simps]:
   \<open>bit (nat k) n \<longleftrightarrow> k \<ge> 0 \<and> bit k n\<close>
 proof (cases \<open>k \<ge> 0\<close>)
   case True
   moreover define m where \<open>m = nat k\<close>
   ultimately have \<open>k = int m\<close>
     by simp
   then show ?thesis
     by (simp add: bit_simps)
 next
   case False
   then show ?thesis
     by simp
 qed
 
 
 subsection \<open>Bit operations\<close>
 
 class semiring_bit_operations = semiring_bits +
   fixes "and" :: \<open>'a \<Rightarrow> 'a \<Rightarrow> 'a\<close>  (infixr \<open>AND\<close> 64)
     and or :: \<open>'a \<Rightarrow> 'a \<Rightarrow> 'a\<close>  (infixr \<open>OR\<close> 59)
     and xor :: \<open>'a \<Rightarrow> 'a \<Rightarrow> 'a\<close>  (infixr \<open>XOR\<close> 59)
     and mask :: \<open>nat \<Rightarrow> 'a\<close>
     and set_bit :: \<open>nat \<Rightarrow> 'a \<Rightarrow> 'a\<close>
     and unset_bit :: \<open>nat \<Rightarrow> 'a \<Rightarrow> 'a\<close>
     and flip_bit :: \<open>nat \<Rightarrow> 'a \<Rightarrow> 'a\<close>
     and push_bit :: \<open>nat \<Rightarrow> 'a \<Rightarrow> 'a\<close>
     and drop_bit :: \<open>nat \<Rightarrow> 'a \<Rightarrow> 'a\<close>
     and take_bit :: \<open>nat \<Rightarrow> 'a \<Rightarrow> 'a\<close>
   assumes and_rec: \<open>a AND b = of_bool (odd a \<and> odd b) + 2 * ((a div 2) AND (b div 2))\<close>
     and or_rec: \<open>a OR b = of_bool (odd a \<or> odd b) + 2 * ((a div 2) OR (b div 2))\<close>
     and xor_rec: \<open>a XOR b = of_bool (odd a \<noteq> odd b) + 2 * ((a div 2) XOR (b div 2))\<close>
     and mask_eq_exp_minus_1: \<open>mask n = 2 ^ n - 1\<close>
     and set_bit_eq_or: \<open>set_bit n a = a OR push_bit n 1\<close>
     and unset_bit_0 [simp]: \<open>unset_bit 0 a = 2 * (a div 2)\<close>
     and unset_bit_Suc: \<open>unset_bit (Suc n) a = a mod 2 + 2 * unset_bit n (a div 2)\<close>
     and flip_bit_eq_xor: \<open>flip_bit n a = a XOR push_bit n 1\<close>
     and push_bit_eq_mult: \<open>push_bit n a = a * 2 ^ n\<close>
     and drop_bit_eq_div: \<open>drop_bit n a = a div 2 ^ n\<close>
     and take_bit_eq_mod: \<open>take_bit n a = a mod 2 ^ n\<close>
 begin
 
 text \<open>
   We want the bitwise operations to bind slightly weaker
   than \<open>+\<close> and \<open>-\<close>.
 
   Logically, \<^const>\<open>push_bit\<close>,
   \<^const>\<open>drop_bit\<close> and \<^const>\<open>take_bit\<close> are just aliases; having them
   as separate operations makes proofs easier, otherwise proof automation
   would fiddle with concrete expressions \<^term>\<open>2 ^ n\<close> in a way obfuscating the basic
   algebraic relationships between those operations.
 
-  For the sake of code generation operations 
+  For the sake of code generation operations
   are specified as definitional class operations,
   taking into account that specific instances of these can be implemented
   differently wrt. code generation.
 \<close>
 
 lemma bit_and_iff [bit_simps]:
   \<open>bit (a AND b) n \<longleftrightarrow> bit a n \<and> bit b n\<close>
 proof (induction n arbitrary: a b)
   case 0
   show ?case
     by (simp add: bit_0 and_rec [of a b] even_bit_succ_iff)
 next
   case (Suc n)
   from Suc [of \<open>a div 2\<close> \<open>b div 2\<close>]
   show ?case
     by (simp add: and_rec [of a b] bit_Suc)
       (auto simp flip: bit_Suc simp add: bit_double_iff dest: bit_imp_possible_bit)
 qed
 
 lemma bit_or_iff [bit_simps]:
   \<open>bit (a OR b) n \<longleftrightarrow> bit a n \<or> bit b n\<close>
 proof (induction n arbitrary: a b)
   case 0
   show ?case
     by (simp add: bit_0 or_rec [of a b] even_bit_succ_iff)
 next
   case (Suc n)
   from Suc [of \<open>a div 2\<close> \<open>b div 2\<close>]
   show ?case
     by (simp add: or_rec [of a b] bit_Suc)
       (auto simp flip: bit_Suc simp add: bit_double_iff dest: bit_imp_possible_bit)
 qed
 
 lemma bit_xor_iff [bit_simps]:
   \<open>bit (a XOR b) n \<longleftrightarrow> bit a n \<noteq> bit b n\<close>
 proof (induction n arbitrary: a b)
   case 0
   show ?case
     by (simp add: bit_0 xor_rec [of a b] even_bit_succ_iff)
 next
   case (Suc n)
   from Suc [of \<open>a div 2\<close> \<open>b div 2\<close>]
   show ?case
     by (simp add: xor_rec [of a b] bit_Suc)
       (auto simp flip: bit_Suc simp add: bit_double_iff dest: bit_imp_possible_bit)
 qed
 
 sublocale "and": semilattice \<open>(AND)\<close>
   by standard (auto simp add: bit_eq_iff bit_and_iff)
 
 sublocale or: semilattice_neutr \<open>(OR)\<close> 0
   by standard (auto simp add: bit_eq_iff bit_or_iff)
 
 sublocale xor: comm_monoid \<open>(XOR)\<close> 0
   by standard (auto simp add: bit_eq_iff bit_xor_iff)
 
 lemma even_and_iff:
   \<open>even (a AND b) \<longleftrightarrow> even a \<or> even b\<close>
   using bit_and_iff [of a b 0] by (auto simp add: bit_0)
 
 lemma even_or_iff:
   \<open>even (a OR b) \<longleftrightarrow> even a \<and> even b\<close>
   using bit_or_iff [of a b 0] by (auto simp add: bit_0)
 
 lemma even_xor_iff:
   \<open>even (a XOR b) \<longleftrightarrow> (even a \<longleftrightarrow> even b)\<close>
   using bit_xor_iff [of a b 0] by (auto simp add: bit_0)
 
 lemma zero_and_eq [simp]:
   \<open>0 AND a = 0\<close>
   by (simp add: bit_eq_iff bit_and_iff)
 
 lemma and_zero_eq [simp]:
   \<open>a AND 0 = 0\<close>
   by (simp add: bit_eq_iff bit_and_iff)
 
 lemma one_and_eq:
   \<open>1 AND a = a mod 2\<close>
   by (simp add: bit_eq_iff bit_and_iff) (auto simp add: bit_1_iff bit_0)
 
 lemma and_one_eq:
   \<open>a AND 1 = a mod 2\<close>
   using one_and_eq [of a] by (simp add: ac_simps)
 
 lemma one_or_eq:
   \<open>1 OR a = a + of_bool (even a)\<close>
   by (simp add: bit_eq_iff bit_or_iff add.commute [of _ 1] even_bit_succ_iff)
     (auto simp add: bit_1_iff bit_0)
 
 lemma or_one_eq:
   \<open>a OR 1 = a + of_bool (even a)\<close>
   using one_or_eq [of a] by (simp add: ac_simps)
 
 lemma one_xor_eq:
   \<open>1 XOR a = a + of_bool (even a) - of_bool (odd a)\<close>
   by (simp add: bit_eq_iff bit_xor_iff add.commute [of _ 1] even_bit_succ_iff)
     (auto simp add: bit_1_iff odd_bit_iff_bit_pred bit_0 elim: oddE)
 
 lemma xor_one_eq:
   \<open>a XOR 1 = a + of_bool (even a) - of_bool (odd a)\<close>
   using one_xor_eq [of a] by (simp add: ac_simps)
 
 lemma xor_self_eq [simp]:
   \<open>a XOR a = 0\<close>
   by (rule bit_eqI) (simp add: bit_simps)
 
 lemma bit_iff_odd_drop_bit:
   \<open>bit a n \<longleftrightarrow> odd (drop_bit n a)\<close>
   by (simp add: bit_iff_odd drop_bit_eq_div)
 
 lemma even_drop_bit_iff_not_bit:
   \<open>even (drop_bit n a) \<longleftrightarrow> \<not> bit a n\<close>
   by (simp add: bit_iff_odd_drop_bit)
 
 lemma div_push_bit_of_1_eq_drop_bit:
   \<open>a div push_bit n 1 = drop_bit n a\<close>
   by (simp add: push_bit_eq_mult drop_bit_eq_div)
 
 lemma bits_ident:
   \<open>push_bit n (drop_bit n a) + take_bit n a = a\<close>
   using div_mult_mod_eq by (simp add: push_bit_eq_mult take_bit_eq_mod drop_bit_eq_div)
 
 lemma push_bit_push_bit [simp]:
   \<open>push_bit m (push_bit n a) = push_bit (m + n) a\<close>
   by (simp add: push_bit_eq_mult power_add ac_simps)
 
 lemma push_bit_0_id [simp]:
   \<open>push_bit 0 = id\<close>
   by (simp add: fun_eq_iff push_bit_eq_mult)
 
 lemma push_bit_of_0 [simp]:
   \<open>push_bit n 0 = 0\<close>
   by (simp add: push_bit_eq_mult)
 
 lemma push_bit_of_1 [simp]:
   \<open>push_bit n 1 = 2 ^ n\<close>
   by (simp add: push_bit_eq_mult)
 
 lemma push_bit_Suc [simp]:
   \<open>push_bit (Suc n) a = push_bit n (a * 2)\<close>
   by (simp add: push_bit_eq_mult ac_simps)
 
 lemma push_bit_double:
   \<open>push_bit n (a * 2) = push_bit n a * 2\<close>
   by (simp add: push_bit_eq_mult ac_simps)
 
 lemma push_bit_add:
   \<open>push_bit n (a + b) = push_bit n a + push_bit n b\<close>
   by (simp add: push_bit_eq_mult algebra_simps)
 
 lemma push_bit_numeral [simp]:
   \<open>push_bit (numeral l) (numeral k) = push_bit (pred_numeral l) (numeral (Num.Bit0 k))\<close>
   by (simp add: numeral_eq_Suc mult_2_right) (simp add: numeral_Bit0)
 
 lemma take_bit_0 [simp]:
   "take_bit 0 a = 0"
   by (simp add: take_bit_eq_mod)
 
 lemma take_bit_Suc:
   \<open>take_bit (Suc n) a = take_bit n (a div 2) * 2 + a mod 2\<close>
 proof -
   have \<open>take_bit (Suc n) (a div 2 * 2 + of_bool (odd a)) = take_bit n (a div 2) * 2 + of_bool (odd a)\<close>
     using even_succ_mod_exp [of \<open>2 * (a div 2)\<close> \<open>Suc n\<close>]
       mult_exp_mod_exp_eq [of 1 \<open>Suc n\<close> \<open>a div 2\<close>]
     by (auto simp add: take_bit_eq_mod ac_simps)
   then show ?thesis
     using div_mult_mod_eq [of a 2] by (simp add: mod_2_eq_odd)
 qed
 
 lemma take_bit_rec:
   \<open>take_bit n a = (if n = 0 then 0 else take_bit (n - 1) (a div 2) * 2 + a mod 2)\<close>
   by (cases n) (simp_all add: take_bit_Suc)
 
 lemma take_bit_Suc_0 [simp]:
   \<open>take_bit (Suc 0) a = a mod 2\<close>
   by (simp add: take_bit_eq_mod)
 
 lemma take_bit_of_0 [simp]:
   \<open>take_bit n 0 = 0\<close>
   by (simp add: take_bit_eq_mod)
 
 lemma take_bit_of_1 [simp]:
   \<open>take_bit n 1 = of_bool (n > 0)\<close>
   by (cases n) (simp_all add: take_bit_Suc)
 
 lemma drop_bit_of_0 [simp]:
   \<open>drop_bit n 0 = 0\<close>
   by (simp add: drop_bit_eq_div)
 
 lemma drop_bit_of_1 [simp]:
   \<open>drop_bit n 1 = of_bool (n = 0)\<close>
   by (simp add: drop_bit_eq_div)
 
 lemma drop_bit_0 [simp]:
   \<open>drop_bit 0 = id\<close>
   by (simp add: fun_eq_iff drop_bit_eq_div)
 
 lemma drop_bit_Suc:
   \<open>drop_bit (Suc n) a = drop_bit n (a div 2)\<close>
   using div_exp_eq [of a 1] by (simp add: drop_bit_eq_div)
 
 lemma drop_bit_rec:
   \<open>drop_bit n a = (if n = 0 then a else drop_bit (n - 1) (a div 2))\<close>
   by (cases n) (simp_all add: drop_bit_Suc)
 
 lemma drop_bit_half:
   \<open>drop_bit n (a div 2) = drop_bit n a div 2\<close>
   by (induction n arbitrary: a) (simp_all add: drop_bit_Suc)
 
 lemma drop_bit_of_bool [simp]:
   \<open>drop_bit n (of_bool b) = of_bool (n = 0 \<and> b)\<close>
   by (cases n) simp_all
 
 lemma even_take_bit_eq [simp]:
   \<open>even (take_bit n a) \<longleftrightarrow> n = 0 \<or> even a\<close>
   by (simp add: take_bit_rec [of n a])
 
 lemma take_bit_take_bit [simp]:
   \<open>take_bit m (take_bit n a) = take_bit (min m n) a\<close>
   by (simp add: take_bit_eq_mod mod_exp_eq ac_simps)
 
 lemma drop_bit_drop_bit [simp]:
   \<open>drop_bit m (drop_bit n a) = drop_bit (m + n) a\<close>
   by (simp add: drop_bit_eq_div power_add div_exp_eq ac_simps)
 
 lemma push_bit_take_bit:
   \<open>push_bit m (take_bit n a) = take_bit (m + n) (push_bit m a)\<close>
   apply (simp add: push_bit_eq_mult take_bit_eq_mod power_add ac_simps)
   using mult_exp_mod_exp_eq [of m \<open>m + n\<close> a] apply (simp add: ac_simps power_add)
   done
 
 lemma take_bit_push_bit:
   \<open>take_bit m (push_bit n a) = push_bit n (take_bit (m - n) a)\<close>
 proof (cases \<open>m \<le> n\<close>)
   case True
   then show ?thesis
     apply (simp add:)
     apply (simp_all add: push_bit_eq_mult take_bit_eq_mod)
     apply (auto dest!: le_Suc_ex simp add: power_add ac_simps)
     using mult_exp_mod_exp_eq [of m m \<open>a * 2 ^ n\<close> for n]
     apply (simp add: ac_simps)
     done
 next
   case False
   then show ?thesis
     using push_bit_take_bit [of n \<open>m - n\<close> a]
     by simp
 qed
 
 lemma take_bit_drop_bit:
   \<open>take_bit m (drop_bit n a) = drop_bit n (take_bit (m + n) a)\<close>
   by (simp add: drop_bit_eq_div take_bit_eq_mod ac_simps div_exp_mod_exp_eq)
 
 lemma drop_bit_take_bit:
   \<open>drop_bit m (take_bit n a) = take_bit (n - m) (drop_bit m a)\<close>
 proof (cases "m \<le> n")
   case True
   then show ?thesis
     using take_bit_drop_bit [of "n - m" m a] by simp
 next
   case False
   then obtain q where \<open>m = n + q\<close>
     by (auto simp add: not_le dest: less_imp_Suc_add)
   then have \<open>drop_bit m (take_bit n a) = 0\<close>
     using div_exp_eq [of \<open>a mod 2 ^ n\<close> n q]
     by (simp add: take_bit_eq_mod drop_bit_eq_div)
   with False show ?thesis
     by simp
 qed
 
 lemma even_push_bit_iff [simp]:
   \<open>even (push_bit n a) \<longleftrightarrow> n \<noteq> 0 \<or> even a\<close>
   by (simp add: push_bit_eq_mult) auto
 
 lemma bit_push_bit_iff [bit_simps]:
   \<open>bit (push_bit m a) n \<longleftrightarrow> m \<le> n \<and> possible_bit TYPE('a) n \<and> bit a (n - m)\<close>
   by (auto simp add: bit_iff_odd push_bit_eq_mult even_mult_exp_div_exp_iff possible_bit_def)
 
 lemma bit_drop_bit_eq [bit_simps]:
   \<open>bit (drop_bit n a) = bit a \<circ> (+) n\<close>
   by (simp add: bit_iff_odd fun_eq_iff ac_simps flip: drop_bit_eq_div)
 
 lemma bit_take_bit_iff [bit_simps]:
   \<open>bit (take_bit m a) n \<longleftrightarrow> n < m \<and> bit a n\<close>
   by (simp add: bit_iff_odd drop_bit_take_bit not_le flip: drop_bit_eq_div)
 
 lemma stable_imp_drop_bit_eq:
   \<open>drop_bit n a = a\<close>
   if \<open>a div 2 = a\<close>
   by (induction n) (simp_all add: that drop_bit_Suc)
 
 lemma stable_imp_take_bit_eq:
   \<open>take_bit n a = (if even a then 0 else 2 ^ n - 1)\<close>
     if \<open>a div 2 = a\<close>
 proof (rule bit_eqI[unfolded possible_bit_def])
   fix m
   assume \<open>2 ^ m \<noteq> 0\<close>
   with that show \<open>bit (take_bit n a) m \<longleftrightarrow> bit (if even a then 0 else 2 ^ n - 1) m\<close>
     by (simp add: bit_take_bit_iff bit_mask_sub_iff possible_bit_def stable_imp_bit_iff_odd)
 qed
 
 lemma exp_dvdE:
   assumes \<open>2 ^ n dvd a\<close>
   obtains b where \<open>a = push_bit n b\<close>
 proof -
   from assms obtain b where \<open>a = 2 ^ n * b\<close> ..
   then have \<open>a = push_bit n b\<close>
     by (simp add: push_bit_eq_mult ac_simps)
   with that show thesis .
 qed
 
 lemma take_bit_eq_0_iff:
   \<open>take_bit n a = 0 \<longleftrightarrow> 2 ^ n dvd a\<close> (is \<open>?P \<longleftrightarrow> ?Q\<close>)
 proof
   assume ?P
   then show ?Q
     by (simp add: take_bit_eq_mod mod_0_imp_dvd)
 next
   assume ?Q
   then obtain b where \<open>a = push_bit n b\<close>
     by (rule exp_dvdE)
   then show ?P
     by (simp add: take_bit_push_bit)
 qed
 
 lemma take_bit_tightened:
-  \<open>take_bit m a = take_bit m b\<close> if \<open>take_bit n a = take_bit n b\<close> and \<open>m \<le> n\<close> 
+  \<open>take_bit m a = take_bit m b\<close> if \<open>take_bit n a = take_bit n b\<close> and \<open>m \<le> n\<close>
 proof -
   from that have \<open>take_bit m (take_bit n a) = take_bit m (take_bit n b)\<close>
     by simp
   then have \<open>take_bit (min m n) a = take_bit (min m n) b\<close>
     by simp
   with that show ?thesis
     by (simp add: min_def)
 qed
 
 lemma take_bit_eq_self_iff_drop_bit_eq_0:
   \<open>take_bit n a = a \<longleftrightarrow> drop_bit n a = 0\<close> (is \<open>?P \<longleftrightarrow> ?Q\<close>)
 proof
   assume ?P
   show ?Q
   proof (rule bit_eqI)
     fix m
     from \<open>?P\<close> have \<open>a = take_bit n a\<close> ..
     also have \<open>\<not> bit (take_bit n a) (n + m)\<close>
       unfolding bit_simps
-      by (simp add: bit_simps) 
+      by (simp add: bit_simps)
     finally show \<open>bit (drop_bit n a) m \<longleftrightarrow> bit 0 m\<close>
       by (simp add: bit_simps)
   qed
 next
   assume ?Q
   show ?P
   proof (rule bit_eqI)
     fix m
     from \<open>?Q\<close> have \<open>\<not> bit (drop_bit n a) (m - n)\<close>
       by simp
     then have \<open> \<not> bit a (n + (m - n))\<close>
       by (simp add: bit_simps)
     then show \<open>bit (take_bit n a) m \<longleftrightarrow> bit a m\<close>
       by (cases \<open>m < n\<close>) (auto simp add: bit_simps)
   qed
 qed
 
 lemma drop_bit_exp_eq:
   \<open>drop_bit m (2 ^ n) = of_bool (m \<le> n \<and> possible_bit TYPE('a) n) * 2 ^ (n - m)\<close>
   by (auto simp add: bit_eq_iff bit_simps)
 
 lemma take_bit_and [simp]:
   \<open>take_bit n (a AND b) = take_bit n a AND take_bit n b\<close>
   by (auto simp add: bit_eq_iff bit_simps)
 
 lemma take_bit_or [simp]:
   \<open>take_bit n (a OR b) = take_bit n a OR take_bit n b\<close>
   by (auto simp add: bit_eq_iff bit_simps)
 
 lemma take_bit_xor [simp]:
   \<open>take_bit n (a XOR b) = take_bit n a XOR take_bit n b\<close>
   by (auto simp add: bit_eq_iff bit_simps)
 
 lemma push_bit_and [simp]:
   \<open>push_bit n (a AND b) = push_bit n a AND push_bit n b\<close>
   by (auto simp add: bit_eq_iff bit_simps)
 
 lemma push_bit_or [simp]:
   \<open>push_bit n (a OR b) = push_bit n a OR push_bit n b\<close>
   by (auto simp add: bit_eq_iff bit_simps)
 
 lemma push_bit_xor [simp]:
   \<open>push_bit n (a XOR b) = push_bit n a XOR push_bit n b\<close>
   by (auto simp add: bit_eq_iff bit_simps)
 
 lemma drop_bit_and [simp]:
   \<open>drop_bit n (a AND b) = drop_bit n a AND drop_bit n b\<close>
   by (auto simp add: bit_eq_iff bit_simps)
 
 lemma drop_bit_or [simp]:
   \<open>drop_bit n (a OR b) = drop_bit n a OR drop_bit n b\<close>
   by (auto simp add: bit_eq_iff bit_simps)
 
 lemma drop_bit_xor [simp]:
   \<open>drop_bit n (a XOR b) = drop_bit n a XOR drop_bit n b\<close>
   by (auto simp add: bit_eq_iff bit_simps)
 
 lemma bit_mask_iff [bit_simps]:
   \<open>bit (mask m) n \<longleftrightarrow> possible_bit TYPE('a) n \<and> n < m\<close>
   by (simp add: mask_eq_exp_minus_1 bit_mask_sub_iff)
 
 lemma even_mask_iff:
   \<open>even (mask n) \<longleftrightarrow> n = 0\<close>
   using bit_mask_iff [of n 0] by (auto simp add: bit_0)
 
 lemma mask_0 [simp]:
   \<open>mask 0 = 0\<close>
   by (simp add: mask_eq_exp_minus_1)
 
 lemma mask_Suc_0 [simp]:
   \<open>mask (Suc 0) = 1\<close>
   by (simp add: mask_eq_exp_minus_1 add_implies_diff sym)
 
 lemma mask_Suc_exp:
   \<open>mask (Suc n) = 2 ^ n OR mask n\<close>
   by (auto simp add: bit_eq_iff bit_simps)
 
 lemma mask_Suc_double:
   \<open>mask (Suc n) = 1 OR 2 * mask n\<close>
   by (auto simp add: bit_eq_iff bit_simps elim: possible_bit_less_imp)
 
 lemma mask_numeral:
   \<open>mask (numeral n) = 1 + 2 * mask (pred_numeral n)\<close>
   by (simp add: numeral_eq_Suc mask_Suc_double one_or_eq ac_simps)
 
 lemma take_bit_of_mask [simp]:
   \<open>take_bit m (mask n) = mask (min m n)\<close>
   by (rule bit_eqI) (simp add: bit_simps)
 
 lemma take_bit_eq_mask:
   \<open>take_bit n a = a AND mask n\<close>
   by (auto simp add: bit_eq_iff bit_simps)
 
 lemma or_eq_0_iff:
   \<open>a OR b = 0 \<longleftrightarrow> a = 0 \<and> b = 0\<close>
   by (auto simp add: bit_eq_iff bit_or_iff)
 
 lemma disjunctive_add:
   \<open>a + b = a OR b\<close> if \<open>\<And>n. \<not> bit a n \<or> \<not> bit b n\<close>
   by (rule bit_eqI) (use that in \<open>simp add: bit_disjunctive_add_iff bit_or_iff\<close>)
 
 lemma bit_iff_and_drop_bit_eq_1:
   \<open>bit a n \<longleftrightarrow> drop_bit n a AND 1 = 1\<close>
   by (simp add: bit_iff_odd_drop_bit and_one_eq odd_iff_mod_2_eq_one)
 
 lemma bit_iff_and_push_bit_not_eq_0:
   \<open>bit a n \<longleftrightarrow> a AND push_bit n 1 \<noteq> 0\<close>
   apply (cases \<open>2 ^ n = 0\<close>)
   apply (simp_all add: bit_eq_iff bit_and_iff bit_push_bit_iff exp_eq_0_imp_not_bit)
   apply (simp_all add: bit_exp_iff)
   done
 
 lemma bit_set_bit_iff [bit_simps]:
   \<open>bit (set_bit m a) n \<longleftrightarrow> bit a n \<or> (m = n \<and> possible_bit TYPE('a) n)\<close>
   by (auto simp add: set_bit_eq_or bit_or_iff bit_exp_iff)
 
 lemma even_set_bit_iff:
   \<open>even (set_bit m a) \<longleftrightarrow> even a \<and> m \<noteq> 0\<close>
   using bit_set_bit_iff [of m a 0] by (auto simp add: bit_0)
 
 lemma bit_unset_bit_iff [bit_simps]:
   \<open>bit (unset_bit m a) n \<longleftrightarrow> bit a n \<and> m \<noteq> n\<close>
 proof (induction m arbitrary: a n)
   case 0
   then show ?case
     by (auto simp add: bit_simps simp flip: bit_Suc dest: bit_imp_possible_bit)
 next
   case (Suc m)
   show ?case
   proof (cases n)
     case 0
     then show ?thesis
       by (cases m) (simp_all add: bit_0 unset_bit_Suc)
   next
     case (Suc n)
     with Suc.IH [of \<open>a div 2\<close> n] show ?thesis
       by (auto simp add: unset_bit_Suc mod_2_eq_odd bit_simps even_bit_succ_iff simp flip: bit_Suc dest: bit_imp_possible_bit)
   qed
 qed
 
 lemma even_unset_bit_iff:
   \<open>even (unset_bit m a) \<longleftrightarrow> even a \<or> m = 0\<close>
   using bit_unset_bit_iff [of m a 0] by (auto simp add: bit_0)
 
 lemma and_exp_eq_0_iff_not_bit:
   \<open>a AND 2 ^ n = 0 \<longleftrightarrow> \<not> bit a n\<close> (is \<open>?P \<longleftrightarrow> ?Q\<close>)
   using bit_imp_possible_bit[of a n]
   by (auto simp add: bit_eq_iff bit_simps)
 
 lemma bit_flip_bit_iff [bit_simps]:
   \<open>bit (flip_bit m a) n \<longleftrightarrow> (m = n \<longleftrightarrow> \<not> bit a n) \<and> possible_bit TYPE('a) n\<close>
   by (auto simp add: bit_eq_iff bit_simps flip_bit_eq_xor bit_imp_possible_bit)
 
 lemma even_flip_bit_iff:
   \<open>even (flip_bit m a) \<longleftrightarrow> \<not> (even a \<longleftrightarrow> m = 0)\<close>
   using bit_flip_bit_iff [of m a 0] by (auto simp: possible_bit_def  bit_0)
 
 lemma set_bit_0 [simp]:
   \<open>set_bit 0 a = 1 + 2 * (a div 2)\<close>
   by (auto simp add: bit_eq_iff bit_simps even_bit_succ_iff simp flip: bit_Suc)
 
 lemma bit_sum_mult_2_cases:
   assumes a: "\<forall>j. \<not> bit a (Suc j)"
   shows "bit (a + 2 * b) n = (if n = 0 then odd a else bit (2 * b) n)"
 proof -
   have a_eq: "bit a i \<longleftrightarrow> i = 0 \<and> odd a" for i
     by (cases i) (simp_all add: a bit_0)
   show ?thesis
     by (simp add: disjunctive_add[simplified disj_imp] a_eq bit_simps)
 qed
 
 lemma set_bit_Suc:
   \<open>set_bit (Suc n) a = a mod 2 + 2 * set_bit n (a div 2)\<close>
   by (auto simp add: bit_eq_iff bit_sum_mult_2_cases bit_simps bit_0 simp flip: bit_Suc
     elim: possible_bit_less_imp)
 
 lemma flip_bit_0 [simp]:
   \<open>flip_bit 0 a = of_bool (even a) + 2 * (a div 2)\<close>
   by (auto simp add: bit_eq_iff bit_simps even_bit_succ_iff bit_0 simp flip: bit_Suc)
 
 lemma flip_bit_Suc:
   \<open>flip_bit (Suc n) a = a mod 2 + 2 * flip_bit n (a div 2)\<close>
   by (auto simp add: bit_eq_iff bit_sum_mult_2_cases bit_simps bit_0 simp flip: bit_Suc
     elim: possible_bit_less_imp)
 
 lemma flip_bit_eq_if:
   \<open>flip_bit n a = (if bit a n then unset_bit else set_bit) n a\<close>
   by (rule bit_eqI) (auto simp add: bit_set_bit_iff bit_unset_bit_iff bit_flip_bit_iff)
 
 lemma take_bit_set_bit_eq:
   \<open>take_bit n (set_bit m a) = (if n \<le> m then take_bit n a else set_bit m (take_bit n a))\<close>
   by (rule bit_eqI) (auto simp add: bit_take_bit_iff bit_set_bit_iff)
 
 lemma take_bit_unset_bit_eq:
   \<open>take_bit n (unset_bit m a) = (if n \<le> m then take_bit n a else unset_bit m (take_bit n a))\<close>
   by (rule bit_eqI) (auto simp add: bit_take_bit_iff bit_unset_bit_iff)
 
 lemma take_bit_flip_bit_eq:
   \<open>take_bit n (flip_bit m a) = (if n \<le> m then take_bit n a else flip_bit m (take_bit n a))\<close>
   by (rule bit_eqI) (auto simp add: bit_take_bit_iff bit_flip_bit_iff)
 
 lemma bit_1_0 [simp]:
   \<open>bit 1 0\<close>
   by (simp add: bit_0)
 
 lemma not_bit_1_Suc [simp]:
   \<open>\<not> bit 1 (Suc n)\<close>
   by (simp add: bit_Suc)
 
 lemma push_bit_Suc_numeral [simp]:
   \<open>push_bit (Suc n) (numeral k) = push_bit n (numeral (Num.Bit0 k))\<close>
   by (simp add: numeral_eq_Suc mult_2_right) (simp add: numeral_Bit0)
 
 lemma mask_eq_0_iff [simp]:
   \<open>mask n = 0 \<longleftrightarrow> n = 0\<close>
   by (cases n) (simp_all add: mask_Suc_double or_eq_0_iff)
 
 lemma bit_horner_sum_bit_iff [bit_simps]:
   \<open>bit (horner_sum of_bool 2 bs) n \<longleftrightarrow> possible_bit TYPE('a) n \<and> n < length bs \<and> bs ! n\<close>
 proof (induction bs arbitrary: n)
   case Nil
   then show ?case
     by simp
 next
   case (Cons b bs)
   show ?case
   proof (cases n)
     case 0
     then show ?thesis
       by (simp add: bit_0)
   next
     case (Suc m)
     with bit_rec [of _ n] Cons.prems Cons.IH [of m]
     show ?thesis
       by (simp add: bit_simps)
         (auto simp add: possible_bit_less_imp bit_simps simp flip: bit_Suc)
   qed
 qed
 
 lemma horner_sum_bit_eq_take_bit:
   \<open>horner_sum of_bool 2 (map (bit a) [0..<n]) = take_bit n a\<close>
   by (rule bit_eqI) (auto simp add: bit_simps)
 
 lemma take_bit_horner_sum_bit_eq:
   \<open>take_bit n (horner_sum of_bool 2 bs) = horner_sum of_bool 2 (take n bs)\<close>
   by (auto simp add: bit_eq_iff bit_take_bit_iff bit_horner_sum_bit_iff)
 
 lemma take_bit_sum:
   \<open>take_bit n a = (\<Sum>k = 0..<n. push_bit k (of_bool (bit a k)))\<close>
   by (simp flip: horner_sum_bit_eq_take_bit add: horner_sum_eq_sum push_bit_eq_mult)
 
-lemmas set_bit_def = set_bit_eq_or
-
-lemmas flip_bit_def = flip_bit_eq_xor
-
 end
 
 class ring_bit_operations = semiring_bit_operations + ring_parity +
   fixes not :: \<open>'a \<Rightarrow> 'a\<close>  (\<open>NOT\<close>)
   assumes not_rec: \<open>NOT a = of_bool (even a) + 2 * NOT (a div 2)\<close>
   assumes minus_eq_not_minus_1: \<open>- a = NOT (a - 1)\<close>
 begin
 
 text \<open>
   For the sake of code generation \<^const>\<open>not\<close> is specified as
   definitional class operation.  Note that \<^const>\<open>not\<close> has no
   sensible definition for unlimited but only positive bit strings
   (type \<^typ>\<open>nat\<close>).
 \<close>
 
 lemma bits_minus_1_mod_2_eq [simp]:
   \<open>(- 1) mod 2 = 1\<close>
   by (simp add: mod_2_eq_odd)
 
 lemma not_eq_complement:
   \<open>NOT a = - a - 1\<close>
   using minus_eq_not_minus_1 [of \<open>a + 1\<close>] by simp
 
 lemma minus_eq_not_plus_1:
   \<open>- a = NOT a + 1\<close>
   using not_eq_complement [of a] by simp
 
 lemma even_not_iff [simp]:
   \<open>even (NOT a) \<longleftrightarrow> odd a\<close>
   by (simp add: not_rec [of a])
 
 lemma bit_not_iff [bit_simps]:
   \<open>bit (NOT a) n \<longleftrightarrow> possible_bit TYPE('a) n \<and> \<not> bit a n\<close>
 proof (cases \<open>possible_bit TYPE('a) n\<close>)
   case False
   then show ?thesis
-    by (auto dest: bit_imp_possible_bit) 
+    by (auto dest: bit_imp_possible_bit)
 next
   case True
   moreover have \<open>bit (NOT a) n \<longleftrightarrow> \<not> bit a n\<close>
   using \<open>possible_bit TYPE('a) n\<close> proof (induction n arbitrary: a)
     case 0
     then show ?case
       by (simp add: bit_0)
   next
     case (Suc n)
     from Suc.prems Suc.IH [of \<open>a div 2\<close>]
     show ?case
       by (simp add: impossible_bit possible_bit_less_imp not_rec [of a] even_bit_succ_iff bit_double_iff flip: bit_Suc)
   qed
   ultimately show ?thesis
     by simp
 qed
 
 lemma bit_not_exp_iff [bit_simps]:
   \<open>bit (NOT (2 ^ m)) n \<longleftrightarrow> possible_bit TYPE('a) n \<and> n \<noteq> m\<close>
   by (auto simp add: bit_not_iff bit_exp_iff)
 
 lemma bit_minus_iff [bit_simps]:
   \<open>bit (- a) n \<longleftrightarrow> possible_bit TYPE('a) n \<and> \<not> bit (a - 1) n\<close>
   by (simp add: minus_eq_not_minus_1 bit_not_iff)
 
 lemma bit_minus_1_iff [simp]:
   \<open>bit (- 1) n \<longleftrightarrow> possible_bit TYPE('a) n\<close>
   by (simp add: bit_minus_iff)
 
 lemma bit_minus_exp_iff [bit_simps]:
   \<open>bit (- (2 ^ m)) n \<longleftrightarrow> possible_bit TYPE('a) n \<and> n \<ge> m\<close>
   by (auto simp add: bit_simps simp flip: mask_eq_exp_minus_1)
 
 lemma bit_minus_2_iff [simp]:
   \<open>bit (- 2) n \<longleftrightarrow> possible_bit TYPE('a) n \<and> n > 0\<close>
   by (simp add: bit_minus_iff bit_1_iff)
 
 lemma bit_not_iff_eq:
   \<open>bit (NOT a) n \<longleftrightarrow> 2 ^ n \<noteq> 0 \<and> \<not> bit a n\<close>
   by (simp add: bit_simps possible_bit_def)
 
 lemma not_one_eq [simp]:
   \<open>NOT 1 = - 2\<close>
   by (simp add: bit_eq_iff bit_not_iff) (simp add: bit_1_iff)
 
 sublocale "and": semilattice_neutr \<open>(AND)\<close> \<open>- 1\<close>
   by standard (rule bit_eqI, simp add: bit_and_iff)
 
 sublocale bit: abstract_boolean_algebra \<open>(AND)\<close> \<open>(OR)\<close> NOT 0 \<open>- 1\<close>
   by standard (auto simp add: bit_and_iff bit_or_iff bit_not_iff intro: bit_eqI)
 
 sublocale bit: abstract_boolean_algebra_sym_diff \<open>(AND)\<close> \<open>(OR)\<close> NOT 0 \<open>- 1\<close> \<open>(XOR)\<close>
   apply standard
   apply (rule bit_eqI)
   apply (auto simp add: bit_simps)
   done
 
 lemma and_eq_not_not_or:
   \<open>a AND b = NOT (NOT a OR NOT b)\<close>
   by simp
 
 lemma or_eq_not_not_and:
   \<open>a OR b = NOT (NOT a AND NOT b)\<close>
   by simp
 
 lemma not_add_distrib:
   \<open>NOT (a + b) = NOT a - b\<close>
   by (simp add: not_eq_complement algebra_simps)
 
 lemma not_diff_distrib:
   \<open>NOT (a - b) = NOT a + b\<close>
   using not_add_distrib [of a \<open>- b\<close>] by simp
 
 lemma and_eq_minus_1_iff:
   \<open>a AND b = - 1 \<longleftrightarrow> a = - 1 \<and> b = - 1\<close>
   by (auto simp: bit_eq_iff bit_simps)
 
 lemma disjunctive_diff:
   \<open>a - b = a AND NOT b\<close> if \<open>\<And>n. bit b n \<Longrightarrow> bit a n\<close>
 proof -
   have \<open>NOT a + b = NOT a OR b\<close>
     by (rule disjunctive_add) (auto simp add: bit_not_iff dest: that)
   then have \<open>NOT (NOT a + b) = NOT (NOT a OR b)\<close>
     by simp
   then show ?thesis
     by (simp add: not_add_distrib)
 qed
 
 lemma push_bit_minus:
   \<open>push_bit n (- a) = - push_bit n a\<close>
   by (simp add: push_bit_eq_mult)
 
 lemma take_bit_not_take_bit:
   \<open>take_bit n (NOT (take_bit n a)) = take_bit n (NOT a)\<close>
   by (auto simp add: bit_eq_iff bit_take_bit_iff bit_not_iff)
 
 lemma take_bit_not_iff:
   \<open>take_bit n (NOT a) = take_bit n (NOT b) \<longleftrightarrow> take_bit n a = take_bit n b\<close>
   apply (simp add: bit_eq_iff)
   apply (simp add: bit_not_iff bit_take_bit_iff bit_exp_iff)
   apply (use exp_eq_0_imp_not_bit in blast)
   done
 
 lemma take_bit_not_eq_mask_diff:
   \<open>take_bit n (NOT a) = mask n - take_bit n a\<close>
 proof -
   have \<open>take_bit n (NOT a) = take_bit n (NOT (take_bit n a))\<close>
     by (simp add: take_bit_not_take_bit)
   also have \<open>\<dots> = mask n AND NOT (take_bit n a)\<close>
     by (simp add: take_bit_eq_mask ac_simps)
   also have \<open>\<dots> = mask n - take_bit n a\<close>
     by (subst disjunctive_diff)
       (auto simp add: bit_take_bit_iff bit_mask_iff bit_imp_possible_bit)
   finally show ?thesis
     by simp
 qed
 
 lemma mask_eq_take_bit_minus_one:
   \<open>mask n = take_bit n (- 1)\<close>
   by (simp add: bit_eq_iff bit_mask_iff bit_take_bit_iff conj_commute)
 
 lemma take_bit_minus_one_eq_mask [simp]:
   \<open>take_bit n (- 1) = mask n\<close>
   by (simp add: mask_eq_take_bit_minus_one)
 
 lemma minus_exp_eq_not_mask:
   \<open>- (2 ^ n) = NOT (mask n)\<close>
   by (rule bit_eqI) (simp add: bit_minus_iff bit_not_iff flip: mask_eq_exp_minus_1)
 
 lemma push_bit_minus_one_eq_not_mask [simp]:
   \<open>push_bit n (- 1) = NOT (mask n)\<close>
   by (simp add: push_bit_eq_mult minus_exp_eq_not_mask)
 
 lemma take_bit_not_mask_eq_0:
   \<open>take_bit m (NOT (mask n)) = 0\<close> if \<open>n \<ge> m\<close>
   by (rule bit_eqI) (use that in \<open>simp add: bit_take_bit_iff bit_not_iff bit_mask_iff\<close>)
 
 lemma unset_bit_eq_and_not:
   \<open>unset_bit n a = a AND NOT (push_bit n 1)\<close>
   by (rule bit_eqI) (auto simp add: bit_simps)
 
 lemma push_bit_Suc_minus_numeral [simp]:
   \<open>push_bit (Suc n) (- numeral k) = push_bit n (- numeral (Num.Bit0 k))\<close>
   apply (simp only: numeral_Bit0)
   apply simp
   apply (simp only: numeral_mult mult_2_right numeral_add)
   done
 
 lemma push_bit_minus_numeral [simp]:
   \<open>push_bit (numeral l) (- numeral k) = push_bit (pred_numeral l) (- numeral (Num.Bit0 k))\<close>
   by (simp only: numeral_eq_Suc push_bit_Suc_minus_numeral)
 
 lemma take_bit_Suc_minus_1_eq:
   \<open>take_bit (Suc n) (- 1) = 2 ^ Suc n - 1\<close>
   by (simp add: mask_eq_exp_minus_1)
 
 lemma take_bit_numeral_minus_1_eq:
   \<open>take_bit (numeral k) (- 1) = 2 ^ numeral k - 1\<close>
   by (simp add: mask_eq_exp_minus_1)
 
 lemma push_bit_mask_eq:
   \<open>push_bit m (mask n) = mask (n + m) AND NOT (mask m)\<close>
   apply (rule bit_eqI)
   apply (auto simp add: bit_simps not_less possible_bit_def)
   apply (drule sym [of 0])
   apply (simp only:)
   using exp_not_zero_imp_exp_diff_not_zero apply (blast dest: exp_not_zero_imp_exp_diff_not_zero)
   done
 
 lemma slice_eq_mask:
   \<open>push_bit n (take_bit m (drop_bit n a)) = a AND mask (m + n) AND NOT (mask n)\<close>
   by (rule bit_eqI) (auto simp add: bit_simps)
 
 lemma push_bit_numeral_minus_1 [simp]:
   \<open>push_bit (numeral n) (- 1) = - (2 ^ numeral n)\<close>
   by (simp add: push_bit_eq_mult)
 
-lemmas unset_bit_def = unset_bit_eq_and_not
-
 end
 
 
 subsection \<open>Instance \<^typ>\<open>int\<close>\<close>
 
 locale fold2_bit_int =
   fixes f :: \<open>bool \<Rightarrow> bool \<Rightarrow> bool\<close>
 begin
 
 context
 begin
 
 function F :: \<open>int \<Rightarrow> int \<Rightarrow> int\<close>
   where \<open>F k l = (if k \<in> {0, - 1} \<and> l \<in> {0, - 1}
     then - of_bool (f (odd k) (odd l))
     else of_bool (f (odd k) (odd l)) + 2 * (F (k div 2) (l div 2)))\<close>
   by auto
 
 private termination proof (relation \<open>measure (\<lambda>(k, l). nat (\<bar>k\<bar> + \<bar>l\<bar>))\<close>)
   have less_eq: \<open>\<bar>k div 2\<bar> \<le> \<bar>k\<bar>\<close> for k :: int
     by (cases k) (simp_all add: divide_int_def nat_add_distrib)
   then have less: \<open>\<bar>k div 2\<bar> < \<bar>k\<bar>\<close> if \<open>k \<notin> {0, - 1}\<close> for k :: int
     using that by (auto simp add: less_le [of k])
   show \<open>wf (measure (\<lambda>(k, l). nat (\<bar>k\<bar> + \<bar>l\<bar>)))\<close>
     by simp
   show \<open>((k div 2, l div 2), k, l) \<in> measure (\<lambda>(k, l). nat (\<bar>k\<bar> + \<bar>l\<bar>))\<close>
     if \<open>\<not> (k \<in> {0, - 1} \<and> l \<in> {0, - 1})\<close> for k l
   proof -
     from that have *: \<open>k \<notin> {0, - 1} \<or> l \<notin> {0, - 1}\<close>
       by simp
     then have \<open>0 < \<bar>k\<bar> + \<bar>l\<bar>\<close>
       by auto
     moreover from * have \<open>\<bar>k div 2\<bar> + \<bar>l div 2\<bar> < \<bar>k\<bar> + \<bar>l\<bar>\<close>
     proof
       assume \<open>k \<notin> {0, - 1}\<close>
       then have \<open>\<bar>k div 2\<bar> < \<bar>k\<bar>\<close>
         by (rule less)
       with less_eq [of l] show ?thesis
         by auto
     next
       assume \<open>l \<notin> {0, - 1}\<close>
       then have \<open>\<bar>l div 2\<bar> < \<bar>l\<bar>\<close>
         by (rule less)
       with less_eq [of k] show ?thesis
         by auto
     qed
     ultimately show ?thesis
       by (simp only: in_measure split_def fst_conv snd_conv nat_mono_iff)
   qed
 qed
 
 declare F.simps [simp del]
 
 lemma rec:
   \<open>F k l = of_bool (f (odd k) (odd l)) + 2 * (F (k div 2) (l div 2))\<close>
     for k l :: int
 proof (cases \<open>k \<in> {0, - 1} \<and> l \<in> {0, - 1}\<close>)
   case True
   then show ?thesis
     by (auto simp add: F.simps [of 0] F.simps [of \<open>- 1\<close>])
 next
   case False
   then show ?thesis
     by (auto simp add: ac_simps F.simps [of k l])
 qed
 
 lemma bit_iff:
   \<open>bit (F k l) n \<longleftrightarrow> f (bit k n) (bit l n)\<close> for k l :: int
 proof (induction n arbitrary: k l)
   case 0
   then show ?case
     by (simp add: rec [of k l] bit_0)
 next
   case (Suc n)
   then show ?case
     by (simp add: rec [of k l] bit_Suc)
 qed
 
 end
 
 end
 
 instantiation int :: ring_bit_operations
 begin
 
 definition not_int :: \<open>int \<Rightarrow> int\<close>
   where \<open>not_int k = - k - 1\<close>
 
-lemma not_int_rec:
-  \<open>NOT k = of_bool (even k) + 2 * NOT (k div 2)\<close> for k :: int
-  by (auto simp add: not_int_def elim: oddE)
-
-lemma even_not_iff_int:
-  \<open>even (NOT k) \<longleftrightarrow> odd k\<close> for k :: int
-  by (simp add: not_int_def)
-
-lemma not_int_div_2:
-  \<open>NOT k div 2 = NOT (k div 2)\<close> for k :: int
-  by (simp add: not_int_def)
-
-lemma bit_not_int_iff:
-  \<open>bit (NOT k) n \<longleftrightarrow> \<not> bit k n\<close>
-  for k :: int
-  by (simp add: bit_not_int_iff' not_int_def)
-
 global_interpretation and_int: fold2_bit_int \<open>(\<and>)\<close>
   defines and_int = and_int.F .
 
 global_interpretation or_int: fold2_bit_int \<open>(\<or>)\<close>
   defines or_int = or_int.F .
 
 global_interpretation xor_int: fold2_bit_int \<open>(\<noteq>)\<close>
   defines xor_int = xor_int.F .
 
 definition mask_int :: \<open>nat \<Rightarrow> int\<close>
   where \<open>mask n = (2 :: int) ^ n - 1\<close>
 
 definition push_bit_int :: \<open>nat \<Rightarrow> int \<Rightarrow> int\<close>
   where \<open>push_bit_int n k = k * 2 ^ n\<close>
 
 definition drop_bit_int :: \<open>nat \<Rightarrow> int \<Rightarrow> int\<close>
   where \<open>drop_bit_int n k = k div 2 ^ n\<close>
 
 definition take_bit_int :: \<open>nat \<Rightarrow> int \<Rightarrow> int\<close>
   where \<open>take_bit_int n k = k mod 2 ^ n\<close>
 
 definition set_bit_int :: \<open>nat \<Rightarrow> int \<Rightarrow> int\<close>
   where \<open>set_bit n k = k OR push_bit n 1\<close> for k :: int
 
 definition unset_bit_int :: \<open>nat \<Rightarrow> int \<Rightarrow> int\<close>
   where \<open>unset_bit n k = k AND NOT (push_bit n 1)\<close> for k :: int
 
 definition flip_bit_int :: \<open>nat \<Rightarrow> int \<Rightarrow> int\<close>
   where \<open>flip_bit n k = k XOR push_bit n 1\<close> for k :: int
 
+lemma bit_not_int_iff:
+  \<open>bit (NOT k) n \<longleftrightarrow> \<not> bit k n\<close>
+  for k :: int
+  by (simp add: bit_not_int_iff' not_int_def)
+
 instance proof
   fix k l :: int and m n :: nat
   show \<open>- k = NOT (k - 1)\<close>
     by (simp add: not_int_def)
   show \<open>NOT k = of_bool (even k) + 2 * NOT (k div 2)\<close>
     by (auto simp add: not_int_def elim: oddE)
   show \<open>unset_bit 0 k = 2 * (k div 2)\<close>
     by (rule bit_eqI)
       (auto simp add: unset_bit_int_def push_bit_int_def and_int.bit_iff bit_not_int_iff bit_simps simp flip: bit_Suc)
   show \<open>unset_bit (Suc n) k = k mod 2 + 2 * unset_bit n (k div 2)\<close>
     by (rule bit_eqI)
       (auto simp add: unset_bit_int_def push_bit_int_def and_int.bit_iff bit_not_int_iff bit_simps mod_2_eq_odd even_bit_succ_iff bit_0 simp flip: bit_Suc)
 qed (fact and_int.rec or_int.rec xor_int.rec mask_int_def set_bit_int_def flip_bit_int_def
   push_bit_int_def drop_bit_int_def take_bit_int_def)+
 
 end
 
-lemmas and_int_rec = and_int.rec
-
-lemmas bit_and_int_iff = and_int.bit_iff
-
-lemmas or_int_rec = or_int.rec
-
-lemmas bit_or_int_iff = or_int.bit_iff
-
-lemmas xor_int_rec = xor_int.rec
-
-lemmas bit_xor_int_iff = xor_int.bit_iff
-
-lemma even_and_iff_int:
-  \<open>even (k AND l) \<longleftrightarrow> even k \<or> even l\<close> for k l :: int
-  by (fact even_and_iff)
+lemma not_int_div_2:
+  \<open>NOT k div 2 = NOT (k div 2)\<close> for k :: int
+  by (simp add: not_int_def)
 
 lemma bit_push_bit_iff_int:
   \<open>bit (push_bit m k) n \<longleftrightarrow> m \<le> n \<and> bit k (n - m)\<close> for k :: int
   by (auto simp add: bit_push_bit_iff)
 
 lemma take_bit_nonnegative [simp]:
   \<open>take_bit n k \<ge> 0\<close> for k :: int
   by (simp add: take_bit_eq_mod)
 
 lemma not_take_bit_negative [simp]:
   \<open>\<not> take_bit n k < 0\<close> for k :: int
   by (simp add: not_less)
 
 lemma take_bit_int_less_exp [simp]:
   \<open>take_bit n k < 2 ^ n\<close> for k :: int
   by (simp add: take_bit_eq_mod)
 
 lemma take_bit_int_eq_self_iff:
   \<open>take_bit n k = k \<longleftrightarrow> 0 \<le> k \<and> k < 2 ^ n\<close> (is \<open>?P \<longleftrightarrow> ?Q\<close>)
   for k :: int
 proof
   assume ?P
   moreover note take_bit_int_less_exp [of n k] take_bit_nonnegative [of n k]
   ultimately show ?Q
     by simp
 next
   assume ?Q
   then show ?P
     by (simp add: take_bit_eq_mod)
 qed
 
 lemma take_bit_int_eq_self:
   \<open>take_bit n k = k\<close> if \<open>0 \<le> k\<close> \<open>k < 2 ^ n\<close> for k :: int
   using that by (simp add: take_bit_int_eq_self_iff)
 
 lemma mask_half_int:
   \<open>mask n div 2 = (mask (n - 1) :: int)\<close>
   by (cases n) (simp_all add: mask_eq_exp_minus_1 algebra_simps)
 
 lemma mask_nonnegative_int [simp]:
   \<open>mask n \<ge> (0::int)\<close>
   by (simp add: mask_eq_exp_minus_1)
 
 lemma not_mask_negative_int [simp]:
   \<open>\<not> mask n < (0::int)\<close>
   by (simp add: not_less)
 
 lemma not_nonnegative_int_iff [simp]:
   \<open>NOT k \<ge> 0 \<longleftrightarrow> k < 0\<close> for k :: int
   by (simp add: not_int_def)
 
 lemma not_negative_int_iff [simp]:
   \<open>NOT k < 0 \<longleftrightarrow> k \<ge> 0\<close> for k :: int
   by (subst Not_eq_iff [symmetric]) (simp add: not_less not_le)
 
 lemma and_nonnegative_int_iff [simp]:
   \<open>k AND l \<ge> 0 \<longleftrightarrow> k \<ge> 0 \<or> l \<ge> 0\<close> for k l :: int
 proof (induction k arbitrary: l rule: int_bit_induct)
   case zero
   then show ?case
     by simp
 next
   case minus
   then show ?case
     by simp
 next
   case (even k)
   then show ?case
-    using and_int_rec [of \<open>k * 2\<close> l]
+    using and_int.rec [of \<open>k * 2\<close> l]
     by (simp add: pos_imp_zdiv_nonneg_iff zero_le_mult_iff)
 next
   case (odd k)
   from odd have \<open>0 \<le> k AND l div 2 \<longleftrightarrow> 0 \<le> k \<or> 0 \<le> l div 2\<close>
     by simp
   then have \<open>0 \<le> (1 + k * 2) div 2 AND l div 2 \<longleftrightarrow> 0 \<le> (1 + k * 2) div 2 \<or> 0 \<le> l div 2\<close>
     by simp
-  with and_int_rec [of \<open>1 + k * 2\<close> l]
+  with and_int.rec [of \<open>1 + k * 2\<close> l]
   show ?case
     by (auto simp add: zero_le_mult_iff not_le)
 qed
 
 lemma and_negative_int_iff [simp]:
   \<open>k AND l < 0 \<longleftrightarrow> k < 0 \<and> l < 0\<close> for k l :: int
   by (subst Not_eq_iff [symmetric]) (simp add: not_less)
 
 lemma and_less_eq:
   \<open>k AND l \<le> k\<close> if \<open>l < 0\<close> for k l :: int
 using that proof (induction k arbitrary: l rule: int_bit_induct)
   case zero
   then show ?case
     by simp
 next
   case minus
   then show ?case
     by simp
 next
   case (even k)
   from even.IH [of \<open>l div 2\<close>] even.hyps even.prems
   show ?case
-    by (simp add: and_int_rec [of _ l])
+    by (simp add: and_int.rec [of _ l])
 next
   case (odd k)
   from odd.IH [of \<open>l div 2\<close>] odd.hyps odd.prems
   show ?case
-    by (simp add: and_int_rec [of _ l])
+    by (simp add: and_int.rec [of _ l])
 qed
 
 lemma or_nonnegative_int_iff [simp]:
   \<open>k OR l \<ge> 0 \<longleftrightarrow> k \<ge> 0 \<and> l \<ge> 0\<close> for k l :: int
   by (simp only: or_eq_not_not_and not_nonnegative_int_iff) simp
 
 lemma or_negative_int_iff [simp]:
   \<open>k OR l < 0 \<longleftrightarrow> k < 0 \<or> l < 0\<close> for k l :: int
   by (subst Not_eq_iff [symmetric]) (simp add: not_less)
 
 lemma or_greater_eq:
   \<open>k OR l \<ge> k\<close> if \<open>l \<ge> 0\<close> for k l :: int
 using that proof (induction k arbitrary: l rule: int_bit_induct)
   case zero
   then show ?case
     by simp
 next
   case minus
   then show ?case
     by simp
 next
   case (even k)
   from even.IH [of \<open>l div 2\<close>] even.hyps even.prems
   show ?case
-    by (simp add: or_int_rec [of _ l])
+    by (simp add: or_int.rec [of _ l])
 next
   case (odd k)
   from odd.IH [of \<open>l div 2\<close>] odd.hyps odd.prems
   show ?case
-    by (simp add: or_int_rec [of _ l])
+    by (simp add: or_int.rec [of _ l])
 qed
 
 lemma xor_nonnegative_int_iff [simp]:
   \<open>k XOR l \<ge> 0 \<longleftrightarrow> (k \<ge> 0 \<longleftrightarrow> l \<ge> 0)\<close> for k l :: int
   by (simp only: bit.xor_def or_nonnegative_int_iff) auto
 
 lemma xor_negative_int_iff [simp]:
   \<open>k XOR l < 0 \<longleftrightarrow> (k < 0) \<noteq> (l < 0)\<close> for k l :: int
   by (subst Not_eq_iff [symmetric]) (auto simp add: not_less)
 
 lemma OR_upper: \<^marker>\<open>contributor \<open>Stefan Berghofer\<close>\<close>
   \<open>x OR y < 2 ^ n\<close> if \<open>0 \<le> x\<close> \<open>x < 2 ^ n\<close> \<open>y < 2 ^ n\<close> for x y :: int
 using that proof (induction x arbitrary: y n rule: int_bit_induct)
   case zero
   then show ?case
     by simp
 next
   case minus
   then show ?case
     by simp
 next
   case (even x)
   from even.IH [of \<open>n - 1\<close> \<open>y div 2\<close>] even.prems even.hyps
-  show ?case 
-    by (cases n) (auto simp add: or_int_rec [of \<open>_ * 2\<close>] elim: oddE)
+  show ?case
+    by (cases n) (auto simp add: or_int.rec [of \<open>_ * 2\<close>] elim: oddE)
 next
   case (odd x)
   from odd.IH [of \<open>n - 1\<close> \<open>y div 2\<close>] odd.prems odd.hyps
   show ?case
-    by (cases n) (auto simp add: or_int_rec [of \<open>1 + _ * 2\<close>], linarith)
+    by (cases n) (auto simp add: or_int.rec [of \<open>1 + _ * 2\<close>], linarith)
 qed
 
 lemma XOR_upper: \<^marker>\<open>contributor \<open>Stefan Berghofer\<close>\<close>
   \<open>x XOR y < 2 ^ n\<close> if \<open>0 \<le> x\<close> \<open>x < 2 ^ n\<close> \<open>y < 2 ^ n\<close> for x y :: int
 using that proof (induction x arbitrary: y n rule: int_bit_induct)
   case zero
   then show ?case
     by simp
 next
   case minus
   then show ?case
     by simp
 next
   case (even x)
   from even.IH [of \<open>n - 1\<close> \<open>y div 2\<close>] even.prems even.hyps
-  show ?case 
-    by (cases n) (auto simp add: xor_int_rec [of \<open>_ * 2\<close>] elim: oddE)
+  show ?case
+    by (cases n) (auto simp add: xor_int.rec [of \<open>_ * 2\<close>] elim: oddE)
 next
   case (odd x)
   from odd.IH [of \<open>n - 1\<close> \<open>y div 2\<close>] odd.prems odd.hyps
   show ?case
-    by (cases n) (auto simp add: xor_int_rec [of \<open>1 + _ * 2\<close>])
+    by (cases n) (auto simp add: xor_int.rec [of \<open>1 + _ * 2\<close>])
 qed
 
 lemma AND_lower [simp]: \<^marker>\<open>contributor \<open>Stefan Berghofer\<close>\<close>
   \<open>0 \<le> x AND y\<close> if \<open>0 \<le> x\<close> for x y :: int
   using that by simp
 
 lemma OR_lower [simp]: \<^marker>\<open>contributor \<open>Stefan Berghofer\<close>\<close>
   \<open>0 \<le> x OR y\<close> if \<open>0 \<le> x\<close> \<open>0 \<le> y\<close> for x y :: int
   using that by simp
 
 lemma XOR_lower [simp]: \<^marker>\<open>contributor \<open>Stefan Berghofer\<close>\<close>
   \<open>0 \<le> x XOR y\<close> if \<open>0 \<le> x\<close> \<open>0 \<le> y\<close> for x y :: int
   using that by simp
 
 lemma AND_upper1 [simp]: \<^marker>\<open>contributor \<open>Stefan Berghofer\<close>\<close>
   \<open>x AND y \<le> x\<close> if \<open>0 \<le> x\<close> for x y :: int
 using that proof (induction x arbitrary: y rule: int_bit_induct)
   case (odd k)
   then have \<open>k AND y div 2 \<le> k\<close>
     by simp
-  then show ?case 
-    by (simp add: and_int_rec [of \<open>1 + _ * 2\<close>])
-qed (simp_all add: and_int_rec [of \<open>_ * 2\<close>])
+  then show ?case
+    by (simp add: and_int.rec [of \<open>1 + _ * 2\<close>])
+qed (simp_all add: and_int.rec [of \<open>_ * 2\<close>])
 
 lemma AND_upper1' [simp]: \<^marker>\<open>contributor \<open>Stefan Berghofer\<close>\<close>
   \<open>y AND x \<le> z\<close> if \<open>0 \<le> y\<close> \<open>y \<le> z\<close> for x y z :: int
   using _ \<open>y \<le> z\<close> by (rule order_trans) (use \<open>0 \<le> y\<close> in simp)
 
 lemma AND_upper1'' [simp]: \<^marker>\<open>contributor \<open>Stefan Berghofer\<close>\<close>
   \<open>y AND x < z\<close> if \<open>0 \<le> y\<close> \<open>y < z\<close> for x y z :: int
   using _ \<open>y < z\<close> by (rule order_le_less_trans) (use \<open>0 \<le> y\<close> in simp)
 
 lemma AND_upper2 [simp]: \<^marker>\<open>contributor \<open>Stefan Berghofer\<close>\<close>
   \<open>x AND y \<le> y\<close> if \<open>0 \<le> y\<close> for x y :: int
   using that AND_upper1 [of y x] by (simp add: ac_simps)
 
 lemma AND_upper2' [simp]: \<^marker>\<open>contributor \<open>Stefan Berghofer\<close>\<close>
   \<open>x AND y \<le> z\<close> if \<open>0 \<le> y\<close> \<open>y \<le> z\<close> for x y :: int
   using that AND_upper1' [of y z x] by (simp add: ac_simps)
 
 lemma AND_upper2'' [simp]: \<^marker>\<open>contributor \<open>Stefan Berghofer\<close>\<close>
   \<open>x AND y < z\<close> if \<open>0 \<le> y\<close> \<open>y < z\<close> for x y :: int
   using that AND_upper1'' [of y z x] by (simp add: ac_simps)
 
 lemma plus_and_or:
   \<open>(x AND y) + (x OR y) = x + y\<close> for x y :: int
 proof (induction x arbitrary: y rule: int_bit_induct)
   case zero
   then show ?case
     by simp
 next
   case minus
   then show ?case
     by simp
 next
   case (even x)
   from even.IH [of \<open>y div 2\<close>]
   show ?case
-    by (auto simp add: and_int_rec [of _ y] or_int_rec [of _ y] elim: oddE)
+    by (auto simp add: and_int.rec [of _ y] or_int.rec [of _ y] elim: oddE)
 next
   case (odd x)
   from odd.IH [of \<open>y div 2\<close>]
   show ?case
-    by (auto simp add: and_int_rec [of _ y] or_int_rec [of _ y] elim: oddE)
+    by (auto simp add: and_int.rec [of _ y] or_int.rec [of _ y] elim: oddE)
 qed
 
 lemma push_bit_minus_one:
   \<open>push_bit n (- 1 :: int) = - (2 ^ n)\<close>
   by (simp add: push_bit_eq_mult)
 
 lemma minus_1_div_exp_eq_int:
   \<open>- 1 div (2 :: int) ^ n = - 1\<close>
   by (induction n) (use div_exp_eq [symmetric, of \<open>- 1 :: int\<close> 1] in \<open>simp_all add: ac_simps\<close>)
 
 lemma drop_bit_minus_one [simp]:
   \<open>drop_bit n (- 1 :: int) = - 1\<close>
   by (simp add: drop_bit_eq_div minus_1_div_exp_eq_int)
 
 lemma take_bit_Suc_from_most:
   \<open>take_bit (Suc n) k = 2 ^ n * of_bool (bit k n) + take_bit n k\<close> for k :: int
   by (simp only: take_bit_eq_mod power_Suc2) (simp_all add: bit_iff_odd odd_iff_mod_2_eq_one zmod_zmult2_eq)
 
 lemma take_bit_minus:
   \<open>take_bit n (- take_bit n k) = take_bit n (- k)\<close>
     for k :: int
   by (simp add: take_bit_eq_mod mod_minus_eq)
 
 lemma take_bit_diff:
   \<open>take_bit n (take_bit n k - take_bit n l) = take_bit n (k - l)\<close>
     for k l :: int
   by (simp add: take_bit_eq_mod mod_diff_eq)
 
 lemma bit_imp_take_bit_positive:
   \<open>0 < take_bit m k\<close> if \<open>n < m\<close> and \<open>bit k n\<close> for k :: int
 proof (rule ccontr)
   assume \<open>\<not> 0 < take_bit m k\<close>
   then have \<open>take_bit m k = 0\<close>
     by (auto simp add: not_less intro: order_antisym)
   then have \<open>bit (take_bit m k) n = bit 0 n\<close>
     by simp
   with that show False
     by (simp add: bit_take_bit_iff)
 qed
 
 lemma take_bit_mult:
   \<open>take_bit n (take_bit n k * take_bit n l) = take_bit n (k * l)\<close>
   for k l :: int
   by (simp add: take_bit_eq_mod mod_mult_eq)
 
 lemma (in ring_1) of_nat_nat_take_bit_eq [simp]:
   \<open>of_nat (nat (take_bit n k)) = of_int (take_bit n k)\<close>
   by simp
 
 lemma take_bit_minus_small_eq:
   \<open>take_bit n (- k) = 2 ^ n - k\<close> if \<open>0 < k\<close> \<open>k \<le> 2 ^ n\<close> for k :: int
 proof -
   define m where \<open>m = nat k\<close>
   with that have \<open>k = int m\<close> and \<open>0 < m\<close> and \<open>m \<le> 2 ^ n\<close>
     by simp_all
   have \<open>(2 ^ n - m) mod 2 ^ n = 2 ^ n - m\<close>
     using \<open>0 < m\<close> by simp
   then have \<open>int ((2 ^ n - m) mod 2 ^ n) = int (2 ^ n - m)\<close>
     by simp
   then have \<open>(2 ^ n - int m) mod 2 ^ n = 2 ^ n - int m\<close>
     using \<open>m \<le> 2 ^ n\<close> by (simp only: of_nat_mod of_nat_diff) simp
   with \<open>k = int m\<close> have \<open>(2 ^ n - k) mod 2 ^ n = 2 ^ n - k\<close>
     by simp
   then show ?thesis
     by (simp add: take_bit_eq_mod)
 qed
 
 lemma drop_bit_push_bit_int:
   \<open>drop_bit m (push_bit n k) = drop_bit (m - n) (push_bit (n - m) k)\<close> for k :: int
   by (cases \<open>m \<le> n\<close>) (auto simp add: mult.left_commute [of _ \<open>2 ^ n\<close>] mult.commute [of _ \<open>2 ^ n\<close>] mult.assoc
     mult.commute [of k] drop_bit_eq_div push_bit_eq_mult not_le power_add dest!: le_Suc_ex less_imp_Suc_add)
 
 lemma push_bit_nonnegative_int_iff [simp]:
   \<open>push_bit n k \<ge> 0 \<longleftrightarrow> k \<ge> 0\<close> for k :: int
   by (simp add: push_bit_eq_mult zero_le_mult_iff power_le_zero_eq)
 
 lemma push_bit_negative_int_iff [simp]:
   \<open>push_bit n k < 0 \<longleftrightarrow> k < 0\<close> for k :: int
   by (subst Not_eq_iff [symmetric]) (simp add: not_less)
 
 lemma drop_bit_nonnegative_int_iff [simp]:
   \<open>drop_bit n k \<ge> 0 \<longleftrightarrow> k \<ge> 0\<close> for k :: int
   by (induction n) (auto simp add: drop_bit_Suc drop_bit_half)
 
 lemma drop_bit_negative_int_iff [simp]:
   \<open>drop_bit n k < 0 \<longleftrightarrow> k < 0\<close> for k :: int
   by (subst Not_eq_iff [symmetric]) (simp add: not_less)
 
 lemma set_bit_nonnegative_int_iff [simp]:
   \<open>set_bit n k \<ge> 0 \<longleftrightarrow> k \<ge> 0\<close> for k :: int
-  by (simp add: set_bit_def)
+  by (simp add: set_bit_eq_or)
 
 lemma set_bit_negative_int_iff [simp]:
   \<open>set_bit n k < 0 \<longleftrightarrow> k < 0\<close> for k :: int
-  by (simp add: set_bit_def)
+  by (simp add: set_bit_eq_or)
 
 lemma unset_bit_nonnegative_int_iff [simp]:
   \<open>unset_bit n k \<ge> 0 \<longleftrightarrow> k \<ge> 0\<close> for k :: int
-  by (simp add: unset_bit_def)
+  by (simp add: unset_bit_eq_and_not)
 
 lemma unset_bit_negative_int_iff [simp]:
   \<open>unset_bit n k < 0 \<longleftrightarrow> k < 0\<close> for k :: int
-  by (simp add: unset_bit_def)
+  by (simp add: unset_bit_eq_and_not)
 
 lemma flip_bit_nonnegative_int_iff [simp]:
   \<open>flip_bit n k \<ge> 0 \<longleftrightarrow> k \<ge> 0\<close> for k :: int
-  by (simp add: flip_bit_def)
+  by (simp add: flip_bit_eq_xor)
 
 lemma flip_bit_negative_int_iff [simp]:
   \<open>flip_bit n k < 0 \<longleftrightarrow> k < 0\<close> for k :: int
-  by (simp add: flip_bit_def)
+  by (simp add: flip_bit_eq_xor)
 
 lemma set_bit_greater_eq:
   \<open>set_bit n k \<ge> k\<close> for k :: int
-  by (simp add: set_bit_def or_greater_eq)
+  by (simp add: set_bit_eq_or or_greater_eq)
 
 lemma unset_bit_less_eq:
   \<open>unset_bit n k \<le> k\<close> for k :: int
-  by (simp add: unset_bit_def and_less_eq)
+  by (simp add: unset_bit_eq_and_not and_less_eq)
 
 lemma set_bit_eq:
   \<open>set_bit n k = k + of_bool (\<not> bit k n) * 2 ^ n\<close> for k :: int
-proof (rule bit_eqI)
-  fix m
-  show \<open>bit (set_bit n k) m \<longleftrightarrow> bit (k + of_bool (\<not> bit k n) * 2 ^ n) m\<close>
-  proof (cases \<open>m = n\<close>)
-    case True
-    then show ?thesis
-      apply (simp add: bit_set_bit_iff)
-      apply (simp add: bit_iff_odd div_plus_div_distrib_dvd_right)
-      done
-  next
-    case False
-    then show ?thesis
-      apply (clarsimp simp add: bit_set_bit_iff)
-      apply (subst disjunctive_add)
-      apply (clarsimp simp add: bit_exp_iff)
-      apply (clarsimp simp add: bit_or_iff bit_exp_iff)
-      done
-  qed
+proof -
+  have \<open>set_bit n k = k OR of_bool (\<not> bit k n) * 2 ^ n\<close>
+    by (rule bit_eqI) (auto simp add: bit_simps)
+  then show ?thesis
+    by (subst disjunctive_add) (auto simp add: bit_simps)
 qed
 
 lemma unset_bit_eq:
   \<open>unset_bit n k = k - of_bool (bit k n) * 2 ^ n\<close> for k :: int
-proof (rule bit_eqI)
-  fix m
-  show \<open>bit (unset_bit n k) m \<longleftrightarrow> bit (k - of_bool (bit k n) * 2 ^ n) m\<close>
-  proof (cases \<open>m = n\<close>)
-    case True
-    then show ?thesis
-      apply (simp add: bit_unset_bit_iff)
-      apply (simp add: bit_iff_odd)
-      using div_plus_div_distrib_dvd_right [of \<open>2 ^ n\<close> \<open>- (2 ^ n)\<close> k]
-      apply (simp add: dvd_neg_div)
-      done
-  next
-    case False
-    then show ?thesis
-      apply (clarsimp simp add: bit_unset_bit_iff)
-      apply (subst disjunctive_diff)
-      apply (clarsimp simp add: bit_exp_iff)
-      apply (clarsimp simp add: bit_and_iff bit_not_iff bit_exp_iff)
-      done
-  qed
+proof -
+  have \<open>unset_bit n k = k AND NOT (of_bool (bit k n) * 2 ^ n)\<close>
+    by (rule bit_eqI) (auto simp add: bit_simps)
+  then show ?thesis
+    by (subst disjunctive_diff) (auto simp add: bit_simps simp flip: push_bit_eq_mult)
 qed
 
 lemma and_int_unfold:
   \<open>k AND l = (if k = 0 \<or> l = 0 then 0 else if k = - 1 then l else if l = - 1 then k
     else (k mod 2) * (l mod 2) + 2 * ((k div 2) AND (l div 2)))\<close> for k l :: int
-  by (auto simp add: and_int_rec [of k l] zmult_eq_1_iff elim: oddE)
+  by (auto simp add: and_int.rec [of k l] zmult_eq_1_iff elim: oddE)
 
 lemma or_int_unfold:
   \<open>k OR l = (if k = - 1 \<or> l = - 1 then - 1 else if k = 0 then l else if l = 0 then k
     else max (k mod 2) (l mod 2) + 2 * ((k div 2) OR (l div 2)))\<close> for k l :: int
-  by (auto simp add: or_int_rec [of k l] elim: oddE)
+  by (auto simp add: or_int.rec [of k l] elim: oddE)
 
 lemma xor_int_unfold:
   \<open>k XOR l = (if k = - 1 then NOT l else if l = - 1 then NOT k else if k = 0 then l else if l = 0 then k
     else \<bar>k mod 2 - l mod 2\<bar> + 2 * ((k div 2) XOR (l div 2)))\<close> for k l :: int
-  by (auto simp add: xor_int_rec [of k l] not_int_def elim!: oddE)
+  by (auto simp add: xor_int.rec [of k l] not_int_def elim!: oddE)
 
 lemma bit_minus_int_iff:
   \<open>bit (- k) n \<longleftrightarrow> bit (NOT (k - 1)) n\<close> for k :: int
   by (simp add: bit_simps)
 
 lemma take_bit_incr_eq:
   \<open>take_bit n (k + 1) = 1 + take_bit n k\<close> if \<open>take_bit n k \<noteq> 2 ^ n - 1\<close> for k :: int
 proof -
   from that have \<open>2 ^ n \<noteq> k mod 2 ^ n + 1\<close>
     by (simp add: take_bit_eq_mod)
   moreover have \<open>k mod 2 ^ n < 2 ^ n\<close>
     by simp
   ultimately have *: \<open>k mod 2 ^ n + 1 < 2 ^ n\<close>
     by linarith
   have \<open>(k + 1) mod 2 ^ n = (k mod 2 ^ n + 1) mod 2 ^ n\<close>
     by (simp add: mod_simps)
   also have \<open>\<dots> = k mod 2 ^ n + 1\<close>
     using * by (simp add: zmod_trivial_iff)
   finally have \<open>(k + 1) mod 2 ^ n = k mod 2 ^ n + 1\<close> .
   then show ?thesis
     by (simp add: take_bit_eq_mod)
 qed
 
 lemma take_bit_decr_eq:
   \<open>take_bit n (k - 1) = take_bit n k - 1\<close> if \<open>take_bit n k \<noteq> 0\<close> for k :: int
 proof -
   from that have \<open>k mod 2 ^ n \<noteq> 0\<close>
     by (simp add: take_bit_eq_mod)
   moreover have \<open>k mod 2 ^ n \<ge> 0\<close> \<open>k mod 2 ^ n < 2 ^ n\<close>
     by simp_all
   ultimately have *: \<open>k mod 2 ^ n > 0\<close>
     by linarith
   have \<open>(k - 1) mod 2 ^ n = (k mod 2 ^ n - 1) mod 2 ^ n\<close>
     by (simp add: mod_simps)
   also have \<open>\<dots> = k mod 2 ^ n - 1\<close>
     by (simp add: zmod_trivial_iff)
       (use \<open>k mod 2 ^ n < 2 ^ n\<close> * in linarith)
   finally have \<open>(k - 1) mod 2 ^ n = k mod 2 ^ n - 1\<close> .
   then show ?thesis
     by (simp add: take_bit_eq_mod)
 qed
 
 lemma take_bit_int_greater_eq:
   \<open>k + 2 ^ n \<le> take_bit n k\<close> if \<open>k < 0\<close> for k :: int
 proof -
   have \<open>k + 2 ^ n \<le> take_bit n (k + 2 ^ n)\<close>
   proof (cases \<open>k > - (2 ^ n)\<close>)
     case False
     then have \<open>k + 2 ^ n \<le> 0\<close>
       by simp
     also note take_bit_nonnegative
     finally show ?thesis .
   next
     case True
     with that have \<open>0 \<le> k + 2 ^ n\<close> and \<open>k + 2 ^ n < 2 ^ n\<close>
       by simp_all
     then show ?thesis
       by (simp only: take_bit_eq_mod mod_pos_pos_trivial)
   qed
   then show ?thesis
     by (simp add: take_bit_eq_mod)
 qed
 
 lemma take_bit_int_less_eq:
   \<open>take_bit n k \<le> k - 2 ^ n\<close> if \<open>2 ^ n \<le> k\<close> and \<open>n > 0\<close> for k :: int
   using that zmod_le_nonneg_dividend [of \<open>k - 2 ^ n\<close> \<open>2 ^ n\<close>]
   by (simp add: take_bit_eq_mod)
 
 lemma take_bit_int_less_eq_self_iff:
   \<open>take_bit n k \<le> k \<longleftrightarrow> 0 \<le> k\<close> (is \<open>?P \<longleftrightarrow> ?Q\<close>) for k :: int
 proof
   assume ?P
   show ?Q
   proof (rule ccontr)
     assume \<open>\<not> 0 \<le> k\<close>
     then have \<open>k < 0\<close>
       by simp
     with \<open>?P\<close>
     have \<open>take_bit n k < 0\<close>
       by (rule le_less_trans)
     then show False
       by simp
   qed
 next
   assume ?Q
   then show ?P
     by (simp add: take_bit_eq_mod zmod_le_nonneg_dividend)
 qed
 
 lemma take_bit_int_less_self_iff:
   \<open>take_bit n k < k \<longleftrightarrow> 2 ^ n \<le> k\<close> for k :: int
   by (auto simp add: less_le take_bit_int_less_eq_self_iff take_bit_int_eq_self_iff
     intro: order_trans [of 0 \<open>2 ^ n\<close> k])
 
 lemma take_bit_int_greater_self_iff:
   \<open>k < take_bit n k \<longleftrightarrow> k < 0\<close> for k :: int
   using take_bit_int_less_eq_self_iff [of n k] by auto
 
 lemma take_bit_int_greater_eq_self_iff:
   \<open>k \<le> take_bit n k \<longleftrightarrow> k < 2 ^ n\<close> for k :: int
   by (auto simp add: le_less take_bit_int_greater_self_iff take_bit_int_eq_self_iff
     dest: sym not_sym intro: less_trans [of k 0 \<open>2 ^ n\<close>])
 
 lemma not_exp_less_eq_0_int [simp]:
   \<open>\<not> 2 ^ n \<le> (0::int)\<close>
   by (simp add: power_le_zero_eq)
 
 lemma int_bit_bound:
   fixes k :: int
   obtains n where \<open>\<And>m. n \<le> m \<Longrightarrow> bit k m \<longleftrightarrow> bit k n\<close>
     and \<open>n > 0 \<Longrightarrow> bit k (n - 1) \<noteq> bit k n\<close>
 proof -
   obtain q where *: \<open>\<And>m. q \<le> m \<Longrightarrow> bit k m \<longleftrightarrow> bit k q\<close>
   proof (cases \<open>k \<ge> 0\<close>)
     case True
     moreover from power_gt_expt [of 2 \<open>nat k\<close>]
     have \<open>nat k < 2 ^ nat k\<close>
       by simp
     then have \<open>int (nat k) < int (2 ^ nat k)\<close>
       by (simp only: of_nat_less_iff)
     ultimately have *: \<open>k div 2 ^ nat k = 0\<close>
       by simp
     show thesis
     proof (rule that [of \<open>nat k\<close>])
       fix m
       assume \<open>nat k \<le> m\<close>
       then show \<open>bit k m \<longleftrightarrow> bit k (nat k)\<close>
         by (auto simp add: * bit_iff_odd power_add zdiv_zmult2_eq dest!: le_Suc_ex)
     qed
   next
     case False
     moreover from power_gt_expt [of 2 \<open>nat (- k)\<close>]
     have \<open>nat (- k) < 2 ^ nat (- k)\<close>
       by simp
     then have \<open>int (nat (- k)) < int (2 ^ nat (- k))\<close>
       by (simp only: of_nat_less_iff)
     ultimately have \<open>- k div - (2 ^ nat (- k)) = - 1\<close>
       by (subst div_pos_neg_trivial) simp_all
     then have *: \<open>k div 2 ^ nat (- k) = - 1\<close>
       by simp
     show thesis
     proof (rule that [of \<open>nat (- k)\<close>])
       fix m
       assume \<open>nat (- k) \<le> m\<close>
       then show \<open>bit k m \<longleftrightarrow> bit k (nat (- k))\<close>
         by (auto simp add: * bit_iff_odd power_add zdiv_zmult2_eq minus_1_div_exp_eq_int dest!: le_Suc_ex)
     qed
   qed
   show thesis
   proof (cases \<open>\<forall>m. bit k m \<longleftrightarrow> bit k q\<close>)
     case True
     then have \<open>bit k 0 \<longleftrightarrow> bit k q\<close>
       by blast
     with True that [of 0] show thesis
       by simp
   next
     case False
     then obtain r where **: \<open>bit k r \<noteq> bit k q\<close>
       by blast
     have \<open>r < q\<close>
       by (rule ccontr) (use * [of r] ** in simp)
     define N where \<open>N = {n. n < q \<and> bit k n \<noteq> bit k q}\<close>
     moreover have \<open>finite N\<close> \<open>r \<in> N\<close>
       using ** N_def \<open>r < q\<close> by auto
     moreover define n where \<open>n = Suc (Max N)\<close>
     ultimately have \<open>\<And>m. n \<le> m \<Longrightarrow> bit k m \<longleftrightarrow> bit k n\<close>
       apply auto
          apply (metis (full_types, lifting) "*" Max_ge_iff Suc_n_not_le_n \<open>finite N\<close> all_not_in_conv mem_Collect_eq not_le)
         apply (metis "*" Max_ge Suc_n_not_le_n \<open>finite N\<close> linorder_not_less mem_Collect_eq)
         apply (metis "*" Max_ge Suc_n_not_le_n \<open>finite N\<close> linorder_not_less mem_Collect_eq)
       apply (metis (full_types, lifting) "*" Max_ge_iff Suc_n_not_le_n \<open>finite N\<close> all_not_in_conv mem_Collect_eq not_le)
       done
     have \<open>bit k (Max N) \<noteq> bit k n\<close>
       by (metis (mono_tags, lifting) "*" Max_in N_def \<open>\<And>m. n \<le> m \<Longrightarrow> bit k m = bit k n\<close> \<open>finite N\<close> \<open>r \<in> N\<close> empty_iff le_cases mem_Collect_eq)
     show thesis apply (rule that [of n])
       using \<open>\<And>m. n \<le> m \<Longrightarrow> bit k m = bit k n\<close> apply blast
       using \<open>bit k (Max N) \<noteq> bit k n\<close> n_def by auto
   qed
 qed
 
 lemma take_bit_tightened_less_eq_int:
   \<open>take_bit m k \<le> take_bit n k\<close> if \<open>m \<le> n\<close> for k :: int
 proof -
   have \<open>take_bit m (take_bit n k) \<le> take_bit n k\<close>
     by (simp only: take_bit_int_less_eq_self_iff take_bit_nonnegative)
   with that show ?thesis
     by simp
 qed
 
 context ring_bit_operations
 begin
 
 lemma even_of_int_iff:
   \<open>even (of_int k) \<longleftrightarrow> even k\<close>
   by (induction k rule: int_bit_induct) simp_all
 
 lemma bit_of_int_iff [bit_simps]:
   \<open>bit (of_int k) n \<longleftrightarrow> possible_bit TYPE('a) n \<and> bit k n\<close>
 proof (cases \<open>possible_bit TYPE('a) n\<close>)
   case False
   then show ?thesis
     by (simp add: impossible_bit)
 next
   case True
   then have \<open>bit (of_int k) n \<longleftrightarrow> bit k n\<close>
   proof (induction k arbitrary: n rule: int_bit_induct)
     case zero
     then show ?case
       by simp
   next
     case minus
     then show ?case
       by simp
   next
     case (even k)
     then show ?case
       using bit_double_iff [of \<open>of_int k\<close> n] Bit_Operations.bit_double_iff [of k n]
       by (cases n) (auto simp add: ac_simps possible_bit_def dest: mult_not_zero)
   next
     case (odd k)
     then show ?case
       using bit_double_iff [of \<open>of_int k\<close> n]
       by (cases n)
         (auto simp add: ac_simps bit_double_iff even_bit_succ_iff Bit_Operations.bit_0 Bit_Operations.bit_Suc
           possible_bit_def dest: mult_not_zero)
   qed
   with True show ?thesis
     by simp
 qed
 
 lemma push_bit_of_int:
   \<open>push_bit n (of_int k) = of_int (push_bit n k)\<close>
   by (simp add: push_bit_eq_mult Bit_Operations.push_bit_eq_mult)
 
 lemma of_int_push_bit:
   \<open>of_int (push_bit n k) = push_bit n (of_int k)\<close>
   by (simp add: push_bit_eq_mult Bit_Operations.push_bit_eq_mult)
 
 lemma take_bit_of_int:
   \<open>take_bit n (of_int k) = of_int (take_bit n k)\<close>
   by (rule bit_eqI) (simp add: bit_take_bit_iff Bit_Operations.bit_take_bit_iff bit_of_int_iff)
 
 lemma of_int_take_bit:
   \<open>of_int (take_bit n k) = take_bit n (of_int k)\<close>
   by (rule bit_eqI) (simp add: bit_take_bit_iff Bit_Operations.bit_take_bit_iff bit_of_int_iff)
 
 lemma of_int_not_eq:
   \<open>of_int (NOT k) = NOT (of_int k)\<close>
   by (rule bit_eqI) (simp add: bit_not_iff Bit_Operations.bit_not_iff bit_of_int_iff)
 
 lemma of_int_not_numeral:
   \<open>of_int (NOT (numeral k)) = NOT (numeral k)\<close>
   by (simp add: local.of_int_not_eq)
 
 lemma of_int_and_eq:
   \<open>of_int (k AND l) = of_int k AND of_int l\<close>
   by (rule bit_eqI) (simp add: bit_of_int_iff bit_and_iff Bit_Operations.bit_and_iff)
 
 lemma of_int_or_eq:
   \<open>of_int (k OR l) = of_int k OR of_int l\<close>
   by (rule bit_eqI) (simp add: bit_of_int_iff bit_or_iff Bit_Operations.bit_or_iff)
 
 lemma of_int_xor_eq:
   \<open>of_int (k XOR l) = of_int k XOR of_int l\<close>
   by (rule bit_eqI) (simp add: bit_of_int_iff bit_xor_iff Bit_Operations.bit_xor_iff)
 
 lemma of_int_mask_eq:
   \<open>of_int (mask n) = mask n\<close>
   by (induction n) (simp_all add: mask_Suc_double Bit_Operations.mask_Suc_double of_int_or_eq)
 
 end
 
 
 subsection \<open>Instance \<^typ>\<open>nat\<close>\<close>
 
 instantiation nat :: semiring_bit_operations
 begin
 
 definition and_nat :: \<open>nat \<Rightarrow> nat \<Rightarrow> nat\<close>
   where \<open>m AND n = nat (int m AND int n)\<close> for m n :: nat
 
 definition or_nat :: \<open>nat \<Rightarrow> nat \<Rightarrow> nat\<close>
   where \<open>m OR n = nat (int m OR int n)\<close> for m n :: nat
 
 definition xor_nat :: \<open>nat \<Rightarrow> nat \<Rightarrow> nat\<close>
   where \<open>m XOR n = nat (int m XOR int n)\<close> for m n :: nat
 
 definition mask_nat :: \<open>nat \<Rightarrow> nat\<close>
   where \<open>mask n = (2 :: nat) ^ n - 1\<close>
 
 definition push_bit_nat :: \<open>nat \<Rightarrow> nat \<Rightarrow> nat\<close>
   where \<open>push_bit_nat n m = m * 2 ^ n\<close>
 
 definition drop_bit_nat :: \<open>nat \<Rightarrow> nat \<Rightarrow> nat\<close>
   where \<open>drop_bit_nat n m = m div 2 ^ n\<close>
 
 definition take_bit_nat :: \<open>nat \<Rightarrow> nat \<Rightarrow> nat\<close>
   where \<open>take_bit_nat n m = m mod 2 ^ n\<close>
 
 definition set_bit_nat :: \<open>nat \<Rightarrow> nat \<Rightarrow> nat\<close>
   where \<open>set_bit m n = n OR push_bit m 1\<close> for m n :: nat
 
 definition unset_bit_nat :: \<open>nat \<Rightarrow> nat \<Rightarrow> nat\<close>
   where \<open>unset_bit m n = nat (unset_bit m (int n))\<close> for m n :: nat
 
 definition flip_bit_nat :: \<open>nat \<Rightarrow> nat \<Rightarrow> nat\<close>
   where \<open>flip_bit m n = n XOR push_bit m 1\<close> for m n :: nat
 
 instance proof
   fix m n :: nat
   show \<open>m AND n = of_bool (odd m \<and> odd n) + 2 * (m div 2 AND n div 2)\<close>
     by (simp add: and_nat_def and_rec [of \<open>int m\<close> \<open>int n\<close>] nat_add_distrib of_nat_div)
   show \<open>m OR n = of_bool (odd m \<or> odd n) + 2 * (m div 2 OR n div 2)\<close>
     by (simp add: or_nat_def or_rec [of \<open>int m\<close> \<open>int n\<close>] nat_add_distrib of_nat_div)
   show \<open>m XOR n = of_bool (odd m \<noteq> odd n) + 2 * (m div 2 XOR n div 2)\<close>
     by (simp add: xor_nat_def xor_rec [of \<open>int m\<close> \<open>int n\<close>] nat_add_distrib of_nat_div)
   show \<open>unset_bit 0 n = 2 * (n div 2)\<close>
     by (simp add: unset_bit_nat_def nat_mult_distrib)
   show \<open>unset_bit (Suc m) n = n mod 2 + 2 * unset_bit m (n div 2)\<close>
     by (simp add: unset_bit_nat_def unset_bit_Suc nat_add_distrib nat_mult_distrib nat_mod_distrib of_nat_div)
 qed (simp_all add: mask_nat_def set_bit_nat_def flip_bit_nat_def push_bit_nat_def drop_bit_nat_def take_bit_nat_def)
 
 end
 
 lemma take_bit_nat_less_exp [simp]:
-  \<open>take_bit n m < 2 ^ n\<close> for n m :: nat 
+  \<open>take_bit n m < 2 ^ n\<close> for n m :: nat
   by (simp add: take_bit_eq_mod)
 
 lemma take_bit_nat_eq_self_iff:
   \<open>take_bit n m = m \<longleftrightarrow> m < 2 ^ n\<close> (is \<open>?P \<longleftrightarrow> ?Q\<close>) for n m :: nat
 proof
   assume ?P
   moreover note take_bit_nat_less_exp [of n m]
   ultimately show ?Q
     by simp
 next
   assume ?Q
   then show ?P
     by (simp add: take_bit_eq_mod)
 qed
 
 lemma take_bit_nat_eq_self:
   \<open>take_bit n m = m\<close> if \<open>m < 2 ^ n\<close> for m n :: nat
   using that by (simp add: take_bit_nat_eq_self_iff)
 
 lemma take_bit_nat_less_eq_self [simp]:
   \<open>take_bit n m \<le> m\<close> for n m :: nat
   by (simp add: take_bit_eq_mod)
 
 lemma take_bit_nat_less_self_iff:
   \<open>take_bit n m < m \<longleftrightarrow> 2 ^ n \<le> m\<close> (is \<open>?P \<longleftrightarrow> ?Q\<close>) for m n :: nat
 proof
   assume ?P
   then have \<open>take_bit n m \<noteq> m\<close>
     by simp
   then show \<open>?Q\<close>
     by (simp add: take_bit_nat_eq_self_iff)
 next
   have \<open>take_bit n m < 2 ^ n\<close>
     by (fact take_bit_nat_less_exp)
   also assume ?Q
   finally show ?P .
 qed
 
 lemma bit_push_bit_iff_nat:
   \<open>bit (push_bit m q) n \<longleftrightarrow> m \<le> n \<and> bit q (n - m)\<close> for q :: nat
   by (auto simp add: bit_push_bit_iff)
 
 lemma and_nat_rec:
   \<open>m AND n = of_bool (odd m \<and> odd n) + 2 * ((m div 2) AND (n div 2))\<close> for m n :: nat
-  by (simp add: and_nat_def and_int_rec [of \<open>int m\<close> \<open>int n\<close>] zdiv_int nat_add_distrib nat_mult_distrib)
+  by (simp add: and_nat_def and_int.rec [of \<open>int m\<close> \<open>int n\<close>] zdiv_int nat_add_distrib nat_mult_distrib)
 
 lemma or_nat_rec:
   \<open>m OR n = of_bool (odd m \<or> odd n) + 2 * ((m div 2) OR (n div 2))\<close> for m n :: nat
-  by (simp add: or_nat_def or_int_rec [of \<open>int m\<close> \<open>int n\<close>] zdiv_int nat_add_distrib nat_mult_distrib)
+  by (simp add: or_nat_def or_int.rec [of \<open>int m\<close> \<open>int n\<close>] zdiv_int nat_add_distrib nat_mult_distrib)
 
 lemma xor_nat_rec:
   \<open>m XOR n = of_bool (odd m \<noteq> odd n) + 2 * ((m div 2) XOR (n div 2))\<close> for m n :: nat
-  by (simp add: xor_nat_def xor_int_rec [of \<open>int m\<close> \<open>int n\<close>] zdiv_int nat_add_distrib nat_mult_distrib)
+  by (simp add: xor_nat_def xor_int.rec [of \<open>int m\<close> \<open>int n\<close>] zdiv_int nat_add_distrib nat_mult_distrib)
 
 lemma Suc_0_and_eq [simp]:
   \<open>Suc 0 AND n = n mod 2\<close>
   using one_and_eq [of n] by simp
 
 lemma and_Suc_0_eq [simp]:
   \<open>n AND Suc 0 = n mod 2\<close>
   using and_one_eq [of n] by simp
 
 lemma Suc_0_or_eq:
   \<open>Suc 0 OR n = n + of_bool (even n)\<close>
   using one_or_eq [of n] by simp
 
 lemma or_Suc_0_eq:
   \<open>n OR Suc 0 = n + of_bool (even n)\<close>
   using or_one_eq [of n] by simp
 
 lemma Suc_0_xor_eq:
   \<open>Suc 0 XOR n = n + of_bool (even n) - of_bool (odd n)\<close>
   using one_xor_eq [of n] by simp
 
 lemma xor_Suc_0_eq:
   \<open>n XOR Suc 0 = n + of_bool (even n) - of_bool (odd n)\<close>
   using xor_one_eq [of n] by simp
 
 lemma and_nat_unfold [code]:
   \<open>m AND n = (if m = 0 \<or> n = 0 then 0 else (m mod 2) * (n mod 2) + 2 * ((m div 2) AND (n div 2)))\<close>
     for m n :: nat
   by (auto simp add: and_nat_rec [of m n] elim: oddE)
 
 lemma or_nat_unfold [code]:
   \<open>m OR n = (if m = 0 then n else if n = 0 then m
     else max (m mod 2) (n mod 2) + 2 * ((m div 2) OR (n div 2)))\<close> for m n :: nat
   by (auto simp add: or_nat_rec [of m n] elim: oddE)
 
 lemma xor_nat_unfold [code]:
   \<open>m XOR n = (if m = 0 then n else if n = 0 then m
     else (m mod 2 + n mod 2) mod 2 + 2 * ((m div 2) XOR (n div 2)))\<close> for m n :: nat
   by (auto simp add: xor_nat_rec [of m n] elim!: oddE)
 
 lemma [code]:
   \<open>unset_bit 0 m = 2 * (m div 2)\<close>
   \<open>unset_bit (Suc n) m = m mod 2 + 2 * unset_bit n (m div 2)\<close> for m n :: nat
   by (simp_all add: unset_bit_Suc)
 
 lemma push_bit_of_Suc_0 [simp]:
   \<open>push_bit n (Suc 0) = 2 ^ n\<close>
   using push_bit_of_1 [where ?'a = nat] by simp
 
 lemma take_bit_of_Suc_0 [simp]:
   \<open>take_bit n (Suc 0) = of_bool (0 < n)\<close>
   using take_bit_of_1 [where ?'a = nat] by simp
 
 lemma drop_bit_of_Suc_0 [simp]:
   \<open>drop_bit n (Suc 0) = of_bool (n = 0)\<close>
   using drop_bit_of_1 [where ?'a = nat] by simp
 
 lemma Suc_mask_eq_exp:
   \<open>Suc (mask n) = 2 ^ n\<close>
   by (simp add: mask_eq_exp_minus_1)
 
 lemma less_eq_mask:
   \<open>n \<le> mask n\<close>
   by (simp add: mask_eq_exp_minus_1 le_diff_conv2)
     (metis Suc_mask_eq_exp diff_Suc_1 diff_le_diff_pow diff_zero le_refl not_less_eq_eq power_0)
 
 lemma less_mask:
   \<open>n < mask n\<close> if \<open>Suc 0 < n\<close>
 proof -
   define m where \<open>m = n - 2\<close>
   with that have *: \<open>n = m + 2\<close>
     by simp
   have \<open>Suc (Suc (Suc m)) < 4 * 2 ^ m\<close>
     by (induction m) simp_all
   then have \<open>Suc (m + 2) < Suc (mask (m + 2))\<close>
     by (simp add: Suc_mask_eq_exp)
   then have \<open>m + 2 < mask (m + 2)\<close>
     by (simp add: less_le)
   with * show ?thesis
     by simp
 qed
 
 lemma mask_nat_less_exp [simp]:
   \<open>(mask n :: nat) < 2 ^ n\<close>
   by (simp add: mask_eq_exp_minus_1)
 
 lemma mask_nat_positive_iff [simp]:
   \<open>(0::nat) < mask n \<longleftrightarrow> 0 < n\<close>
 proof (cases \<open>n = 0\<close>)
   case True
   then show ?thesis
     by simp
 next
   case False
   then have \<open>0 < n\<close>
     by simp
   then have \<open>(0::nat) < mask n\<close>
     using less_eq_mask [of n] by (rule order_less_le_trans)
   with \<open>0 < n\<close> show ?thesis
     by simp
 qed
 
 lemma take_bit_tightened_less_eq_nat:
   \<open>take_bit m q \<le> take_bit n q\<close> if \<open>m \<le> n\<close> for q :: nat
 proof -
   have \<open>take_bit m (take_bit n q) \<le> take_bit n q\<close>
     by (rule take_bit_nat_less_eq_self)
   with that show ?thesis
     by simp
 qed
 
 lemma push_bit_nat_eq:
   \<open>push_bit n (nat k) = nat (push_bit n k)\<close>
   by (cases \<open>k \<ge> 0\<close>) (simp_all add: push_bit_eq_mult nat_mult_distrib not_le mult_nonneg_nonpos2)
 
 lemma drop_bit_nat_eq:
   \<open>drop_bit n (nat k) = nat (drop_bit n k)\<close>
   apply (cases \<open>k \<ge> 0\<close>)
    apply (simp_all add: drop_bit_eq_div nat_div_distrib nat_power_eq not_le)
   apply (simp add: divide_int_def)
   done
 
 lemma take_bit_nat_eq:
   \<open>take_bit n (nat k) = nat (take_bit n k)\<close> if \<open>k \<ge> 0\<close>
   using that by (simp add: take_bit_eq_mod nat_mod_distrib nat_power_eq)
 
 lemma nat_take_bit_eq:
   \<open>nat (take_bit n k) = take_bit n (nat k)\<close>
   if \<open>k \<ge> 0\<close>
   using that by (simp add: take_bit_eq_mod nat_mod_distrib nat_power_eq)
 
 context semiring_bit_operations
 begin
 
 lemma push_bit_of_nat:
   \<open>push_bit n (of_nat m) = of_nat (push_bit n m)\<close>
   by (simp add: push_bit_eq_mult Bit_Operations.push_bit_eq_mult)
 
 lemma of_nat_push_bit:
   \<open>of_nat (push_bit m n) = push_bit m (of_nat n)\<close>
   by (simp add: push_bit_eq_mult Bit_Operations.push_bit_eq_mult)
 
 lemma take_bit_of_nat:
   \<open>take_bit n (of_nat m) = of_nat (take_bit n m)\<close>
   by (rule bit_eqI) (simp add: bit_take_bit_iff Bit_Operations.bit_take_bit_iff bit_of_nat_iff)
 
 lemma of_nat_take_bit:
   \<open>of_nat (take_bit n m) = take_bit n (of_nat m)\<close>
   by (rule bit_eqI) (simp add: bit_take_bit_iff Bit_Operations.bit_take_bit_iff bit_of_nat_iff)
 
 lemma of_nat_and_eq:
   \<open>of_nat (m AND n) = of_nat m AND of_nat n\<close>
   by (rule bit_eqI) (simp add: bit_of_nat_iff bit_and_iff Bit_Operations.bit_and_iff)
 
 lemma of_nat_or_eq:
   \<open>of_nat (m OR n) = of_nat m OR of_nat n\<close>
   by (rule bit_eqI) (simp add: bit_of_nat_iff bit_or_iff Bit_Operations.bit_or_iff)
 
 lemma of_nat_xor_eq:
   \<open>of_nat (m XOR n) = of_nat m XOR of_nat n\<close>
   by (rule bit_eqI) (simp add: bit_of_nat_iff bit_xor_iff Bit_Operations.bit_xor_iff)
 
 lemma of_nat_mask_eq:
   \<open>of_nat (mask n) = mask n\<close>
   by (induction n) (simp_all add: mask_Suc_double Bit_Operations.mask_Suc_double of_nat_or_eq)
 
 end
 
 lemma nat_mask_eq:
   \<open>nat (mask n) = mask n\<close>
   by (simp add: nat_eq_iff of_nat_mask_eq)
 
 
 subsection \<open>Common algebraic structure\<close>
 
 class linordered_euclidean_semiring_bit_operations =
   linordered_euclidean_semiring + semiring_bit_operations
 begin
 
 lemma possible_bit [simp]:
   \<open>possible_bit TYPE('a) n\<close>
   by (simp add: possible_bit_def)
 
 lemma take_bit_of_exp [simp]:
   \<open>take_bit m (2 ^ n) = of_bool (n < m) * 2 ^ n\<close>
   by (simp add: take_bit_eq_mod exp_mod_exp)
 
 lemma take_bit_of_2 [simp]:
   \<open>take_bit n 2 = of_bool (2 \<le> n) * 2\<close>
   using take_bit_of_exp [of n 1] by simp
 
 lemma push_bit_eq_0_iff [simp]:
   \<open>push_bit n a = 0 \<longleftrightarrow> a = 0\<close>
   by (simp add: push_bit_eq_mult)
 
 lemma take_bit_add:
   \<open>take_bit n (take_bit n a + take_bit n b) = take_bit n (a + b)\<close>
   by (simp add: take_bit_eq_mod mod_simps)
 
 lemma take_bit_of_1_eq_0_iff [simp]:
   \<open>take_bit n 1 = 0 \<longleftrightarrow> n = 0\<close>
   by (simp add: take_bit_eq_mod)
 
 lemma drop_bit_Suc_bit0 [simp]:
   \<open>drop_bit (Suc n) (numeral (Num.Bit0 k)) = drop_bit n (numeral k)\<close>
   by (simp add: drop_bit_Suc numeral_Bit0_div_2)
 
 lemma drop_bit_Suc_bit1 [simp]:
   \<open>drop_bit (Suc n) (numeral (Num.Bit1 k)) = drop_bit n (numeral k)\<close>
   by (simp add: drop_bit_Suc numeral_Bit1_div_2)
 
 lemma drop_bit_numeral_bit0 [simp]:
   \<open>drop_bit (numeral l) (numeral (Num.Bit0 k)) = drop_bit (pred_numeral l) (numeral k)\<close>
   by (simp add: drop_bit_rec numeral_Bit0_div_2)
 
 lemma drop_bit_numeral_bit1 [simp]:
   \<open>drop_bit (numeral l) (numeral (Num.Bit1 k)) = drop_bit (pred_numeral l) (numeral k)\<close>
   by (simp add: drop_bit_rec numeral_Bit1_div_2)
 
 lemma take_bit_Suc_1 [simp]:
   \<open>take_bit (Suc n) 1 = 1\<close>
   by (simp add: take_bit_Suc)
 
 lemma take_bit_Suc_bit0:
   \<open>take_bit (Suc n) (numeral (Num.Bit0 k)) = take_bit n (numeral k) * 2\<close>
   by (simp add: take_bit_Suc numeral_Bit0_div_2)
 
 lemma take_bit_Suc_bit1:
   \<open>take_bit (Suc n) (numeral (Num.Bit1 k)) = take_bit n (numeral k) * 2 + 1\<close>
   by (simp add: take_bit_Suc numeral_Bit1_div_2 mod_2_eq_odd)
 
 lemma take_bit_numeral_1 [simp]:
   \<open>take_bit (numeral l) 1 = 1\<close>
   by (simp add: take_bit_rec [of \<open>numeral l\<close> 1])
 
 lemma take_bit_numeral_bit0:
   \<open>take_bit (numeral l) (numeral (Num.Bit0 k)) = take_bit (pred_numeral l) (numeral k) * 2\<close>
   by (simp add: take_bit_rec numeral_Bit0_div_2)
 
 lemma take_bit_numeral_bit1:
   \<open>take_bit (numeral l) (numeral (Num.Bit1 k)) = take_bit (pred_numeral l) (numeral k) * 2 + 1\<close>
   by (simp add: take_bit_rec numeral_Bit1_div_2 mod_2_eq_odd)
 
 lemma bit_of_nat_iff_bit [bit_simps]:
   \<open>bit (of_nat m) n \<longleftrightarrow> bit m n\<close>
 proof -
   have \<open>even (m div 2 ^ n) \<longleftrightarrow> even (of_nat (m div 2 ^ n))\<close>
     by simp
   also have \<open>of_nat (m div 2 ^ n) = of_nat m div of_nat (2 ^ n)\<close>
     by (simp add: of_nat_div)
   finally show ?thesis
     by (simp add: bit_iff_odd semiring_bits_class.bit_iff_odd)
 qed
 
 lemma drop_bit_mask_eq:
   \<open>drop_bit m (mask n) = mask (n - m)\<close>
   by (rule bit_eqI) (auto simp add: bit_simps possible_bit_def)
 
 lemma drop_bit_of_nat:
   "drop_bit n (of_nat m) = of_nat (drop_bit n m)"
   by (simp add: drop_bit_eq_div Bit_Operations.drop_bit_eq_div of_nat_div [of m "2 ^ n"])
 
 lemma of_nat_drop_bit:
   \<open>of_nat (drop_bit m n) = drop_bit m (of_nat n)\<close>
   by (simp add: drop_bit_eq_div Bit_Operations.drop_bit_eq_div of_nat_div)
 
 end
 
 instance nat :: linordered_euclidean_semiring_bit_operations ..
 
 instance int :: linordered_euclidean_semiring_bit_operations ..
 
 
 subsection \<open>Symbolic computations on numeral expressions\<close>
 
 context semiring_bits
 begin
 
 lemma not_bit_numeral_Bit0_0 [simp]:
   \<open>\<not> bit (numeral (Num.Bit0 m)) 0\<close>
   by (simp add: bit_0)
 
 lemma bit_numeral_Bit1_0 [simp]:
   \<open>bit (numeral (Num.Bit1 m)) 0\<close>
   by (simp add: bit_0)
 
 end
 
 context ring_bit_operations
 begin
 
 lemma not_bit_minus_numeral_Bit0_0 [simp]:
   \<open>\<not> bit (- numeral (Num.Bit0 m)) 0\<close>
   by (simp add: bit_0)
 
 lemma bit_minus_numeral_Bit1_0 [simp]:
   \<open>bit (- numeral (Num.Bit1 m)) 0\<close>
   by (simp add: bit_0)
 
 end
 
 context linordered_euclidean_semiring_bit_operations
 begin
 
 lemma bit_numeral_iff:
   \<open>bit (numeral m) n \<longleftrightarrow> bit (numeral m :: nat) n\<close>
   using bit_of_nat_iff_bit [of \<open>numeral m\<close> n] by simp
 
 lemma bit_numeral_Bit0_Suc_iff [simp]:
   \<open>bit (numeral (Num.Bit0 m)) (Suc n) \<longleftrightarrow> bit (numeral m) n\<close>
   by (simp add: bit_Suc numeral_Bit0_div_2)
 
 lemma bit_numeral_Bit1_Suc_iff [simp]:
   \<open>bit (numeral (Num.Bit1 m)) (Suc n) \<longleftrightarrow> bit (numeral m) n\<close>
   by (simp add: bit_Suc numeral_Bit1_div_2)
 
 lemma bit_numeral_rec:
   \<open>bit (numeral (Num.Bit0 w)) n \<longleftrightarrow> (case n of 0 \<Rightarrow> False | Suc m \<Rightarrow> bit (numeral w) m)\<close>
   \<open>bit (numeral (Num.Bit1 w)) n \<longleftrightarrow> (case n of 0 \<Rightarrow> True | Suc m \<Rightarrow> bit (numeral w) m)\<close>
   by (cases n; simp add: bit_0)+
 
 lemma bit_numeral_simps [simp]:
   \<open>\<not> bit 1 (numeral n)\<close>
   \<open>bit (numeral (Num.Bit0 w)) (numeral n) \<longleftrightarrow> bit (numeral w) (pred_numeral n)\<close>
   \<open>bit (numeral (Num.Bit1 w)) (numeral n) \<longleftrightarrow> bit (numeral w) (pred_numeral n)\<close>
   by (simp_all add: bit_1_iff numeral_eq_Suc)
 
 lemma and_numerals [simp]:
   \<open>1 AND numeral (Num.Bit0 y) = 0\<close>
   \<open>1 AND numeral (Num.Bit1 y) = 1\<close>
   \<open>numeral (Num.Bit0 x) AND numeral (Num.Bit0 y) = 2 * (numeral x AND numeral y)\<close>
   \<open>numeral (Num.Bit0 x) AND numeral (Num.Bit1 y) = 2 * (numeral x AND numeral y)\<close>
   \<open>numeral (Num.Bit0 x) AND 1 = 0\<close>
   \<open>numeral (Num.Bit1 x) AND numeral (Num.Bit0 y) = 2 * (numeral x AND numeral y)\<close>
   \<open>numeral (Num.Bit1 x) AND numeral (Num.Bit1 y) = 1 + 2 * (numeral x AND numeral y)\<close>
   \<open>numeral (Num.Bit1 x) AND 1 = 1\<close>
   by (simp_all add: bit_eq_iff) (simp_all add: bit_0 bit_simps bit_Suc bit_numeral_rec split: nat.splits)
 
 fun and_num :: \<open>num \<Rightarrow> num \<Rightarrow> num option\<close> \<^marker>\<open>contributor \<open>Andreas Lochbihler\<close>\<close>
 where
   \<open>and_num num.One num.One = Some num.One\<close>
 | \<open>and_num num.One (num.Bit0 n) = None\<close>
 | \<open>and_num num.One (num.Bit1 n) = Some num.One\<close>
 | \<open>and_num (num.Bit0 m) num.One = None\<close>
 | \<open>and_num (num.Bit0 m) (num.Bit0 n) = map_option num.Bit0 (and_num m n)\<close>
 | \<open>and_num (num.Bit0 m) (num.Bit1 n) = map_option num.Bit0 (and_num m n)\<close>
 | \<open>and_num (num.Bit1 m) num.One = Some num.One\<close>
 | \<open>and_num (num.Bit1 m) (num.Bit0 n) = map_option num.Bit0 (and_num m n)\<close>
 | \<open>and_num (num.Bit1 m) (num.Bit1 n) = (case and_num m n of None \<Rightarrow> Some num.One | Some n' \<Rightarrow> Some (num.Bit1 n'))\<close>
 
 lemma numeral_and_num:
   \<open>numeral m AND numeral n = (case and_num m n of None \<Rightarrow> 0 | Some n' \<Rightarrow> numeral n')\<close>
   by (induction m n rule: and_num.induct) (simp_all add: split: option.split)
 
 lemma and_num_eq_None_iff:
   \<open>and_num m n = None \<longleftrightarrow> numeral m AND numeral n = 0\<close>
   by (simp add: numeral_and_num split: option.split)
 
 lemma and_num_eq_Some_iff:
   \<open>and_num m n = Some q \<longleftrightarrow> numeral m AND numeral n = numeral q\<close>
   by (simp add: numeral_and_num split: option.split)
 
 lemma or_numerals [simp]:
   \<open>1 OR numeral (Num.Bit0 y) = numeral (Num.Bit1 y)\<close>
   \<open>1 OR numeral (Num.Bit1 y) = numeral (Num.Bit1 y)\<close>
   \<open>numeral (Num.Bit0 x) OR numeral (Num.Bit0 y) = 2 * (numeral x OR numeral y)\<close>
   \<open>numeral (Num.Bit0 x) OR numeral (Num.Bit1 y) = 1 + 2 * (numeral x OR numeral y)\<close>
   \<open>numeral (Num.Bit0 x) OR 1 = numeral (Num.Bit1 x)\<close>
   \<open>numeral (Num.Bit1 x) OR numeral (Num.Bit0 y) = 1 + 2 * (numeral x OR numeral y)\<close>
   \<open>numeral (Num.Bit1 x) OR numeral (Num.Bit1 y) = 1 + 2 * (numeral x OR numeral y)\<close>
   \<open>numeral (Num.Bit1 x) OR 1 = numeral (Num.Bit1 x)\<close>
   by (simp_all add: bit_eq_iff) (simp_all add: bit_0 bit_simps bit_Suc bit_numeral_rec split: nat.splits)
 
 fun or_num :: \<open>num \<Rightarrow> num \<Rightarrow> num\<close> \<^marker>\<open>contributor \<open>Andreas Lochbihler\<close>\<close>
 where
   \<open>or_num num.One num.One = num.One\<close>
 | \<open>or_num num.One (num.Bit0 n) = num.Bit1 n\<close>
 | \<open>or_num num.One (num.Bit1 n) = num.Bit1 n\<close>
 | \<open>or_num (num.Bit0 m) num.One = num.Bit1 m\<close>
 | \<open>or_num (num.Bit0 m) (num.Bit0 n) = num.Bit0 (or_num m n)\<close>
 | \<open>or_num (num.Bit0 m) (num.Bit1 n) = num.Bit1 (or_num m n)\<close>
 | \<open>or_num (num.Bit1 m) num.One = num.Bit1 m\<close>
 | \<open>or_num (num.Bit1 m) (num.Bit0 n) = num.Bit1 (or_num m n)\<close>
 | \<open>or_num (num.Bit1 m) (num.Bit1 n) = num.Bit1 (or_num m n)\<close>
 
 lemma numeral_or_num:
   \<open>numeral m OR numeral n = numeral (or_num m n)\<close>
   by (induction m n rule: or_num.induct) simp_all
 
 lemma numeral_or_num_eq:
   \<open>numeral (or_num m n) = numeral m OR numeral n\<close>
   by (simp add: numeral_or_num)
 
 lemma xor_numerals [simp]:
   \<open>1 XOR numeral (Num.Bit0 y) = numeral (Num.Bit1 y)\<close>
   \<open>1 XOR numeral (Num.Bit1 y) = numeral (Num.Bit0 y)\<close>
   \<open>numeral (Num.Bit0 x) XOR numeral (Num.Bit0 y) = 2 * (numeral x XOR numeral y)\<close>
   \<open>numeral (Num.Bit0 x) XOR numeral (Num.Bit1 y) = 1 + 2 * (numeral x XOR numeral y)\<close>
   \<open>numeral (Num.Bit0 x) XOR 1 = numeral (Num.Bit1 x)\<close>
   \<open>numeral (Num.Bit1 x) XOR numeral (Num.Bit0 y) = 1 + 2 * (numeral x XOR numeral y)\<close>
   \<open>numeral (Num.Bit1 x) XOR numeral (Num.Bit1 y) = 2 * (numeral x XOR numeral y)\<close>
   \<open>numeral (Num.Bit1 x) XOR 1 = numeral (Num.Bit0 x)\<close>
   by (simp_all add: bit_eq_iff) (simp_all add: bit_0 bit_simps bit_Suc bit_numeral_rec split: nat.splits)
 
 fun xor_num :: \<open>num \<Rightarrow> num \<Rightarrow> num option\<close> \<^marker>\<open>contributor \<open>Andreas Lochbihler\<close>\<close>
 where
   \<open>xor_num num.One num.One = None\<close>
 | \<open>xor_num num.One (num.Bit0 n) = Some (num.Bit1 n)\<close>
 | \<open>xor_num num.One (num.Bit1 n) = Some (num.Bit0 n)\<close>
 | \<open>xor_num (num.Bit0 m) num.One = Some (num.Bit1 m)\<close>
 | \<open>xor_num (num.Bit0 m) (num.Bit0 n) = map_option num.Bit0 (xor_num m n)\<close>
 | \<open>xor_num (num.Bit0 m) (num.Bit1 n) = Some (case xor_num m n of None \<Rightarrow> num.One | Some n' \<Rightarrow> num.Bit1 n')\<close>
 | \<open>xor_num (num.Bit1 m) num.One = Some (num.Bit0 m)\<close>
 | \<open>xor_num (num.Bit1 m) (num.Bit0 n) = Some (case xor_num m n of None \<Rightarrow> num.One | Some n' \<Rightarrow> num.Bit1 n')\<close>
 | \<open>xor_num (num.Bit1 m) (num.Bit1 n) = map_option num.Bit0 (xor_num m n)\<close>
 
 lemma numeral_xor_num:
   \<open>numeral m XOR numeral n = (case xor_num m n of None \<Rightarrow> 0 | Some n' \<Rightarrow> numeral n')\<close>
   by (induction m n rule: xor_num.induct) (simp_all split: option.split)
 
 lemma xor_num_eq_None_iff:
   \<open>xor_num m n = None \<longleftrightarrow> numeral m XOR numeral n = 0\<close>
   by (simp add: numeral_xor_num split: option.split)
 
 lemma xor_num_eq_Some_iff:
   \<open>xor_num m n = Some q \<longleftrightarrow> numeral m XOR numeral n = numeral q\<close>
   by (simp add: numeral_xor_num split: option.split)
 
 end
 
 lemma drop_bit_Suc_minus_bit0 [simp]:
   \<open>drop_bit (Suc n) (- numeral (Num.Bit0 k)) = drop_bit n (- numeral k :: int)\<close>
   by (simp add: drop_bit_Suc numeral_Bit0_div_2)
 
 lemma drop_bit_Suc_minus_bit1 [simp]:
   \<open>drop_bit (Suc n) (- numeral (Num.Bit1 k)) = drop_bit n (- numeral (Num.inc k) :: int)\<close>
   by (simp add: drop_bit_Suc numeral_Bit1_div_2 add_One)
 
 lemma drop_bit_numeral_minus_bit0 [simp]:
   \<open>drop_bit (numeral l) (- numeral (Num.Bit0 k)) = drop_bit (pred_numeral l) (- numeral k :: int)\<close>
   by (simp add: numeral_eq_Suc numeral_Bit0_div_2)
 
 lemma drop_bit_numeral_minus_bit1 [simp]:
   \<open>drop_bit (numeral l) (- numeral (Num.Bit1 k)) = drop_bit (pred_numeral l) (- numeral (Num.inc k) :: int)\<close>
   by (simp add: numeral_eq_Suc numeral_Bit1_div_2)
 
 lemma take_bit_Suc_minus_bit0:
   \<open>take_bit (Suc n) (- numeral (Num.Bit0 k)) = take_bit n (- numeral k) * (2 :: int)\<close>
   by (simp add: take_bit_Suc numeral_Bit0_div_2)
 
 lemma take_bit_Suc_minus_bit1:
   \<open>take_bit (Suc n) (- numeral (Num.Bit1 k)) = take_bit n (- numeral (Num.inc k)) * 2 + (1 :: int)\<close>
   by (simp add: take_bit_Suc numeral_Bit1_div_2 add_One)
 
 lemma take_bit_numeral_minus_bit0:
   \<open>take_bit (numeral l) (- numeral (Num.Bit0 k)) = take_bit (pred_numeral l) (- numeral k) * (2 :: int)\<close>
   by (simp add: numeral_eq_Suc numeral_Bit0_div_2 take_bit_Suc_minus_bit0)
 
 lemma take_bit_numeral_minus_bit1:
   \<open>take_bit (numeral l) (- numeral (Num.Bit1 k)) = take_bit (pred_numeral l) (- numeral (Num.inc k)) * 2 + (1 :: int)\<close>
   by (simp add: numeral_eq_Suc numeral_Bit1_div_2 take_bit_Suc_minus_bit1)
 
 lemma bit_Suc_0_iff [bit_simps]:
   \<open>bit (Suc 0) n \<longleftrightarrow> n = 0\<close>
   using bit_1_iff [of n, where ?'a = nat] by simp
 
 lemma and_nat_numerals [simp]:
   \<open>Suc 0 AND numeral (Num.Bit0 y) = 0\<close>
   \<open>Suc 0 AND numeral (Num.Bit1 y) = 1\<close>
   \<open>numeral (Num.Bit0 x) AND Suc 0 = 0\<close>
   \<open>numeral (Num.Bit1 x) AND Suc 0 = 1\<close>
   by (simp_all only: and_numerals flip: One_nat_def)
 
 lemma or_nat_numerals [simp]:
   \<open>Suc 0 OR numeral (Num.Bit0 y) = numeral (Num.Bit1 y)\<close>
   \<open>Suc 0 OR numeral (Num.Bit1 y) = numeral (Num.Bit1 y)\<close>
   \<open>numeral (Num.Bit0 x) OR Suc 0 = numeral (Num.Bit1 x)\<close>
   \<open>numeral (Num.Bit1 x) OR Suc 0 = numeral (Num.Bit1 x)\<close>
   by (simp_all only: or_numerals flip: One_nat_def)
 
 lemma xor_nat_numerals [simp]:
   \<open>Suc 0 XOR numeral (Num.Bit0 y) = numeral (Num.Bit1 y)\<close>
   \<open>Suc 0 XOR numeral (Num.Bit1 y) = numeral (Num.Bit0 y)\<close>
   \<open>numeral (Num.Bit0 x) XOR Suc 0 = numeral (Num.Bit1 x)\<close>
   \<open>numeral (Num.Bit1 x) XOR Suc 0 = numeral (Num.Bit0 x)\<close>
   by (simp_all only: xor_numerals flip: One_nat_def)
 
 context ring_bit_operations
 begin
 
 lemma minus_numeral_inc_eq:
   \<open>- numeral (Num.inc n) = NOT (numeral n)\<close>
   by (simp add: not_eq_complement sub_inc_One_eq add_One)
 
 lemma sub_one_eq_not_neg:
   \<open>Num.sub n num.One = NOT (- numeral n)\<close>
   by (simp add: not_eq_complement)
 
 lemma minus_numeral_eq_not_sub_one:
   \<open>- numeral n = NOT (Num.sub n num.One)\<close>
   by (simp add: not_eq_complement)
 
 lemma not_numeral_eq [simp]:
   \<open>NOT (numeral n) = - numeral (Num.inc n)\<close>
   by (simp add: minus_numeral_inc_eq)
 
 lemma not_minus_numeral_eq [simp]:
   \<open>NOT (- numeral n) = Num.sub n num.One\<close>
   by (simp add: sub_one_eq_not_neg)
 
 lemma minus_not_numeral_eq [simp]:
   \<open>- (NOT (numeral n)) = numeral (Num.inc n)\<close>
   by simp
 
 lemma not_numeral_BitM_eq:
   \<open>NOT (numeral (Num.BitM n)) =  - numeral (num.Bit0 n)\<close>
-  by (simp add: inc_BitM_eq) 
+  by (simp add: inc_BitM_eq)
 
 lemma not_numeral_Bit0_eq:
   \<open>NOT (numeral (Num.Bit0 n)) =  - numeral (num.Bit1 n)\<close>
   by simp
 
 end
 
 lemma bit_minus_numeral_int [simp]:
   \<open>bit (- numeral (num.Bit0 w) :: int) (numeral n) \<longleftrightarrow> bit (- numeral w :: int) (pred_numeral n)\<close>
   \<open>bit (- numeral (num.Bit1 w) :: int) (numeral n) \<longleftrightarrow> \<not> bit (numeral w :: int) (pred_numeral n)\<close>
   by (simp_all add: bit_minus_iff bit_not_iff numeral_eq_Suc bit_Suc add_One sub_inc_One_eq)
 
 lemma bit_minus_numeral_Bit0_Suc_iff [simp]:
   \<open>bit (- numeral (num.Bit0 w) :: int) (Suc n) \<longleftrightarrow> bit (- numeral w :: int) n\<close>
   by (simp add: bit_Suc)
 
 lemma bit_minus_numeral_Bit1_Suc_iff [simp]:
   \<open>bit (- numeral (num.Bit1 w) :: int) (Suc n) \<longleftrightarrow> \<not> bit (numeral w :: int) n\<close>
   by (simp add: bit_Suc add_One flip: bit_not_int_iff)
 
 lemma and_not_numerals:
   \<open>1 AND NOT 1 = (0 :: int)\<close>
   \<open>1 AND NOT (numeral (Num.Bit0 n)) = (1 :: int)\<close>
   \<open>1 AND NOT (numeral (Num.Bit1 n)) = (0 :: int)\<close>
   \<open>numeral (Num.Bit0 m) AND NOT (1 :: int) = numeral (Num.Bit0 m)\<close>
   \<open>numeral (Num.Bit0 m) AND NOT (numeral (Num.Bit0 n)) = (2 :: int) * (numeral m AND NOT (numeral n))\<close>
   \<open>numeral (Num.Bit0 m) AND NOT (numeral (Num.Bit1 n)) = (2 :: int) * (numeral m AND NOT (numeral n))\<close>
   \<open>numeral (Num.Bit1 m) AND NOT (1 :: int) = numeral (Num.Bit0 m)\<close>
   \<open>numeral (Num.Bit1 m) AND NOT (numeral (Num.Bit0 n)) = 1 + (2 :: int) * (numeral m AND NOT (numeral n))\<close>
   \<open>numeral (Num.Bit1 m) AND NOT (numeral (Num.Bit1 n)) = (2 :: int) * (numeral m AND NOT (numeral n))\<close>
   by (simp_all add: bit_eq_iff) (auto simp add: bit_0 bit_simps bit_Suc bit_numeral_rec BitM_inc_eq sub_inc_One_eq split: nat.split)
 
 fun and_not_num :: \<open>num \<Rightarrow> num \<Rightarrow> num option\<close> \<^marker>\<open>contributor \<open>Andreas Lochbihler\<close>\<close>
 where
   \<open>and_not_num num.One num.One = None\<close>
 | \<open>and_not_num num.One (num.Bit0 n) = Some num.One\<close>
 | \<open>and_not_num num.One (num.Bit1 n) = None\<close>
 | \<open>and_not_num (num.Bit0 m) num.One = Some (num.Bit0 m)\<close>
 | \<open>and_not_num (num.Bit0 m) (num.Bit0 n) = map_option num.Bit0 (and_not_num m n)\<close>
 | \<open>and_not_num (num.Bit0 m) (num.Bit1 n) = map_option num.Bit0 (and_not_num m n)\<close>
 | \<open>and_not_num (num.Bit1 m) num.One = Some (num.Bit0 m)\<close>
 | \<open>and_not_num (num.Bit1 m) (num.Bit0 n) = (case and_not_num m n of None \<Rightarrow> Some num.One | Some n' \<Rightarrow> Some (num.Bit1 n'))\<close>
 | \<open>and_not_num (num.Bit1 m) (num.Bit1 n) = map_option num.Bit0 (and_not_num m n)\<close>
 
 lemma int_numeral_and_not_num:
   \<open>numeral m AND NOT (numeral n) = (case and_not_num m n of None \<Rightarrow> 0 :: int | Some n' \<Rightarrow> numeral n')\<close>
   by (induction m n rule: and_not_num.induct) (simp_all del: not_numeral_eq not_one_eq add: and_not_numerals split: option.splits)
 
 lemma int_numeral_not_and_num:
   \<open>NOT (numeral m) AND numeral n = (case and_not_num n m of None \<Rightarrow> 0 :: int | Some n' \<Rightarrow> numeral n')\<close>
   using int_numeral_and_not_num [of n m] by (simp add: ac_simps)
 
 lemma and_not_num_eq_None_iff:
   \<open>and_not_num m n = None \<longleftrightarrow> numeral m AND NOT (numeral n) = (0 :: int)\<close>
   by (simp del: not_numeral_eq add: int_numeral_and_not_num split: option.split)
 
 lemma and_not_num_eq_Some_iff:
   \<open>and_not_num m n = Some q \<longleftrightarrow> numeral m AND NOT (numeral n) = (numeral q :: int)\<close>
   by (simp del: not_numeral_eq add: int_numeral_and_not_num split: option.split)
 
 lemma and_minus_numerals [simp]:
   \<open>1 AND - (numeral (num.Bit0 n)) = (0::int)\<close>
   \<open>1 AND - (numeral (num.Bit1 n)) = (1::int)\<close>
   \<open>numeral m AND - (numeral (num.Bit0 n)) = (case and_not_num m (Num.BitM n) of None \<Rightarrow> 0 :: int | Some n' \<Rightarrow> numeral n')\<close>
   \<open>numeral m AND - (numeral (num.Bit1 n)) = (case and_not_num m (Num.Bit0 n) of None \<Rightarrow> 0 :: int | Some n' \<Rightarrow> numeral n')\<close>
   \<open>- (numeral (num.Bit0 n)) AND 1 = (0::int)\<close>
   \<open>- (numeral (num.Bit1 n)) AND 1 = (1::int)\<close>
   \<open>- (numeral (num.Bit0 n)) AND numeral m = (case and_not_num m (Num.BitM n) of None \<Rightarrow> 0 :: int | Some n' \<Rightarrow> numeral n')\<close>
   \<open>- (numeral (num.Bit1 n)) AND numeral m = (case and_not_num m (Num.Bit0 n) of None \<Rightarrow> 0 :: int | Some n' \<Rightarrow> numeral n')\<close>
   by (simp_all del: not_numeral_eq add: ac_simps
     and_not_numerals one_and_eq not_numeral_BitM_eq not_numeral_Bit0_eq and_not_num_eq_None_iff and_not_num_eq_Some_iff split: option.split)
 
 lemma and_minus_minus_numerals [simp]:
   \<open>- (numeral m :: int) AND - (numeral n :: int) = NOT ((numeral m - 1) OR (numeral n - 1))\<close>
   by (simp add: minus_numeral_eq_not_sub_one)
 
 lemma or_not_numerals:
   \<open>1 OR NOT 1 = NOT (0 :: int)\<close>
   \<open>1 OR NOT (numeral (Num.Bit0 n)) = NOT (numeral (Num.Bit0 n) :: int)\<close>
   \<open>1 OR NOT (numeral (Num.Bit1 n)) = NOT (numeral (Num.Bit0 n) :: int)\<close>
   \<open>numeral (Num.Bit0 m) OR NOT (1 :: int) = NOT (1 :: int)\<close>
   \<open>numeral (Num.Bit0 m) OR NOT (numeral (Num.Bit0 n)) = 1 + (2 :: int) * (numeral m OR NOT (numeral n))\<close>
   \<open>numeral (Num.Bit0 m) OR NOT (numeral (Num.Bit1 n)) = (2 :: int) * (numeral m OR NOT (numeral n))\<close>
   \<open>numeral (Num.Bit1 m) OR NOT (1 :: int) = NOT (0 :: int)\<close>
   \<open>numeral (Num.Bit1 m) OR NOT (numeral (Num.Bit0 n)) = 1 + (2 :: int) * (numeral m OR NOT (numeral n))\<close>
   \<open>numeral (Num.Bit1 m) OR NOT (numeral (Num.Bit1 n)) = 1 + (2 :: int) * (numeral m OR NOT (numeral n))\<close>
   by (simp_all add: bit_eq_iff)
     (auto simp add: bit_0 bit_simps bit_Suc bit_numeral_rec sub_inc_One_eq split: nat.split)
 
 fun or_not_num_neg :: \<open>num \<Rightarrow> num \<Rightarrow> num\<close> \<^marker>\<open>contributor \<open>Andreas Lochbihler\<close>\<close>
 where
   \<open>or_not_num_neg num.One num.One = num.One\<close>
 | \<open>or_not_num_neg num.One (num.Bit0 m) = num.Bit1 m\<close>
 | \<open>or_not_num_neg num.One (num.Bit1 m) = num.Bit1 m\<close>
 | \<open>or_not_num_neg (num.Bit0 n) num.One = num.Bit0 num.One\<close>
 | \<open>or_not_num_neg (num.Bit0 n) (num.Bit0 m) = Num.BitM (or_not_num_neg n m)\<close>
 | \<open>or_not_num_neg (num.Bit0 n) (num.Bit1 m) = num.Bit0 (or_not_num_neg n m)\<close>
 | \<open>or_not_num_neg (num.Bit1 n) num.One = num.One\<close>
 | \<open>or_not_num_neg (num.Bit1 n) (num.Bit0 m) = Num.BitM (or_not_num_neg n m)\<close>
 | \<open>or_not_num_neg (num.Bit1 n) (num.Bit1 m) = Num.BitM (or_not_num_neg n m)\<close>
 
 lemma int_numeral_or_not_num_neg:
   \<open>numeral m OR NOT (numeral n :: int) = - numeral (or_not_num_neg m n)\<close>
   by (induction m n rule: or_not_num_neg.induct) (simp_all del: not_numeral_eq not_one_eq add: or_not_numerals, simp_all)
 
 lemma int_numeral_not_or_num_neg:
   \<open>NOT (numeral m) OR (numeral n :: int) = - numeral (or_not_num_neg n m)\<close>
   using int_numeral_or_not_num_neg [of n m] by (simp add: ac_simps)
 
 lemma numeral_or_not_num_eq:
   \<open>numeral (or_not_num_neg m n) = - (numeral m OR NOT (numeral n :: int))\<close>
   using int_numeral_or_not_num_neg [of m n] by simp
 
 lemma or_minus_numerals [simp]:
   \<open>1 OR - (numeral (num.Bit0 n)) = - (numeral (or_not_num_neg num.One (Num.BitM n)) :: int)\<close>
   \<open>1 OR - (numeral (num.Bit1 n)) = - (numeral (num.Bit1 n) :: int)\<close>
   \<open>numeral m OR - (numeral (num.Bit0 n)) = - (numeral (or_not_num_neg m (Num.BitM n)) :: int)\<close>
   \<open>numeral m OR - (numeral (num.Bit1 n)) = - (numeral (or_not_num_neg m (Num.Bit0 n)) :: int)\<close>
   \<open>- (numeral (num.Bit0 n)) OR 1 = - (numeral (or_not_num_neg num.One (Num.BitM n)) :: int)\<close>
   \<open>- (numeral (num.Bit1 n)) OR 1 = - (numeral (num.Bit1 n) :: int)\<close>
   \<open>- (numeral (num.Bit0 n)) OR numeral m = - (numeral (or_not_num_neg m (Num.BitM n)) :: int)\<close>
   \<open>- (numeral (num.Bit1 n)) OR numeral m = - (numeral (or_not_num_neg m (Num.Bit0 n)) :: int)\<close>
   by (simp_all only: or.commute [of _ 1] or.commute [of _ \<open>numeral m\<close>]
     minus_numeral_eq_not_sub_one or_not_numerals
     numeral_or_not_num_eq arith_simps minus_minus numeral_One)
 
 lemma or_minus_minus_numerals [simp]:
   \<open>- (numeral m :: int) OR - (numeral n :: int) = NOT ((numeral m - 1) AND (numeral n - 1))\<close>
   by (simp add: minus_numeral_eq_not_sub_one)
 
 lemma xor_minus_numerals [simp]:
   \<open>- numeral n XOR k = NOT (neg_numeral_class.sub n num.One XOR k)\<close>
   \<open>k XOR - numeral n = NOT (k XOR (neg_numeral_class.sub n num.One))\<close> for k :: int
   by (simp_all add: minus_numeral_eq_not_sub_one)
 
 definition take_bit_num :: \<open>nat \<Rightarrow> num \<Rightarrow> num option\<close>
   where \<open>take_bit_num n m =
     (if take_bit n (numeral m :: nat) = 0 then None else Some (num_of_nat (take_bit n (numeral m :: nat))))\<close>
 
 lemma take_bit_num_simps:
   \<open>take_bit_num 0 m = None\<close>
   \<open>take_bit_num (Suc n) Num.One =
     Some Num.One\<close>
   \<open>take_bit_num (Suc n) (Num.Bit0 m) =
     (case take_bit_num n m of None \<Rightarrow> None | Some q \<Rightarrow> Some (Num.Bit0 q))\<close>
   \<open>take_bit_num (Suc n) (Num.Bit1 m) =
     Some (case take_bit_num n m of None \<Rightarrow> Num.One | Some q \<Rightarrow> Num.Bit1 q)\<close>
   \<open>take_bit_num (numeral r) Num.One =
     Some Num.One\<close>
   \<open>take_bit_num (numeral r) (Num.Bit0 m) =
     (case take_bit_num (pred_numeral r) m of None \<Rightarrow> None | Some q \<Rightarrow> Some (Num.Bit0 q))\<close>
   \<open>take_bit_num (numeral r) (Num.Bit1 m) =
     Some (case take_bit_num (pred_numeral r) m of None \<Rightarrow> Num.One | Some q \<Rightarrow> Num.Bit1 q)\<close>
   by (auto simp add: take_bit_num_def ac_simps mult_2 num_of_nat_double
     take_bit_Suc_bit0 take_bit_Suc_bit1 take_bit_numeral_bit0 take_bit_numeral_bit1)
 
 lemma take_bit_num_code [code]:
   \<comment> \<open>Ocaml-style pattern matching is more robust wrt. different representations of \<^typ>\<open>nat\<close>\<close>
   \<open>take_bit_num n m = (case (n, m)
    of (0, _) \<Rightarrow> None
     | (Suc n, Num.One) \<Rightarrow> Some Num.One
     | (Suc n, Num.Bit0 m) \<Rightarrow> (case take_bit_num n m of None \<Rightarrow> None | Some q \<Rightarrow> Some (Num.Bit0 q))
     | (Suc n, Num.Bit1 m) \<Rightarrow> Some (case take_bit_num n m of None \<Rightarrow> Num.One | Some q \<Rightarrow> Num.Bit1 q))\<close>
   by (cases n; cases m) (simp_all add: take_bit_num_simps)
 
 context semiring_bit_operations
 begin
 
 lemma take_bit_num_eq_None_imp:
   \<open>take_bit m (numeral n) = 0\<close> if \<open>take_bit_num m n = None\<close>
 proof -
   from that have \<open>take_bit m (numeral n :: nat) = 0\<close>
     by (simp add: take_bit_num_def split: if_splits)
   then have \<open>of_nat (take_bit m (numeral n)) = of_nat 0\<close>
     by simp
   then show ?thesis
     by (simp add: of_nat_take_bit)
 qed
-    
+
 lemma take_bit_num_eq_Some_imp:
   \<open>take_bit m (numeral n) = numeral q\<close> if \<open>take_bit_num m n = Some q\<close>
 proof -
   from that have \<open>take_bit m (numeral n :: nat) = numeral q\<close>
     by (auto simp add: take_bit_num_def Num.numeral_num_of_nat_unfold split: if_splits)
   then have \<open>of_nat (take_bit m (numeral n)) = of_nat (numeral q)\<close>
     by simp
   then show ?thesis
     by (simp add: of_nat_take_bit)
 qed
 
 lemma take_bit_numeral_numeral:
   \<open>take_bit (numeral m) (numeral n) =
     (case take_bit_num (numeral m) n of None \<Rightarrow> 0 | Some q \<Rightarrow> numeral q)\<close>
   by (auto split: option.split dest: take_bit_num_eq_None_imp take_bit_num_eq_Some_imp)
 
 end
 
 lemma take_bit_numeral_minus_numeral_int:
   \<open>take_bit (numeral m) (- numeral n :: int) =
     (case take_bit_num (numeral m) n of None \<Rightarrow> 0 | Some q \<Rightarrow> take_bit (numeral m) (2 ^ numeral m - numeral q))\<close> (is \<open>?lhs = ?rhs\<close>)
 proof (cases \<open>take_bit_num (numeral m) n\<close>)
   case None
   then show ?thesis
     by (auto dest: take_bit_num_eq_None_imp [where ?'a = int] simp add: take_bit_eq_0_iff)
 next
   case (Some q)
   then have q: \<open>take_bit (numeral m) (numeral n :: int) = numeral q\<close>
     by (auto dest: take_bit_num_eq_Some_imp)
   let ?T = \<open>take_bit (numeral m) :: int \<Rightarrow> int\<close>
   have *: \<open>?T (2 ^ numeral m) = ?T (?T 0)\<close>
     by (simp add: take_bit_eq_0_iff)
   have \<open>?lhs = ?T (0 - numeral n)\<close>
     by simp
   also have \<open>\<dots> = ?T (?T (?T 0) - ?T (?T (numeral n)))\<close>
     by (simp only: take_bit_diff)
   also have \<open>\<dots> = ?T (2 ^ numeral m - ?T (numeral n))\<close>
     by (simp only: take_bit_diff flip: *)
   also have \<open>\<dots> = ?rhs\<close>
     by (simp add: q Some)
   finally show ?thesis .
 qed
 
 declare take_bit_num_simps [simp]
   take_bit_numeral_numeral [simp]
   take_bit_numeral_minus_numeral_int [simp]
 
 
 subsection \<open>More properties\<close>
 
 lemma take_bit_eq_mask_iff:
   \<open>take_bit n k = mask n \<longleftrightarrow> take_bit n (k + 1) = 0\<close> (is \<open>?P \<longleftrightarrow> ?Q\<close>)
   for k :: int
 proof
   assume ?P
   then have \<open>take_bit n (take_bit n k + take_bit n 1) = 0\<close>
     by (simp add: mask_eq_exp_minus_1 take_bit_eq_0_iff)
   then show ?Q
     by (simp only: take_bit_add)
 next
   assume ?Q
   then have \<open>take_bit n (k + 1) - 1 = - 1\<close>
     by simp
   then have \<open>take_bit n (take_bit n (k + 1) - 1) = take_bit n (- 1)\<close>
     by simp
   moreover have \<open>take_bit n (take_bit n (k + 1) - 1) = take_bit n k\<close>
     by (simp add: take_bit_eq_mod mod_simps)
   ultimately show ?P
     by simp
 qed
 
 lemma take_bit_eq_mask_iff_exp_dvd:
   \<open>take_bit n k = mask n \<longleftrightarrow> 2 ^ n dvd k + 1\<close>
   for k :: int
   by (simp add: take_bit_eq_mask_iff flip: take_bit_eq_0_iff)
 
 
 subsection \<open>Bit concatenation\<close>
 
 definition concat_bit :: \<open>nat \<Rightarrow> int \<Rightarrow> int \<Rightarrow> int\<close>
   where \<open>concat_bit n k l = take_bit n k OR push_bit n l\<close>
 
 lemma bit_concat_bit_iff [bit_simps]:
   \<open>bit (concat_bit m k l) n \<longleftrightarrow> n < m \<and> bit k n \<or> m \<le> n \<and> bit l (n - m)\<close>
   by (simp add: concat_bit_def bit_or_iff bit_and_iff bit_take_bit_iff bit_push_bit_iff ac_simps)
 
 lemma concat_bit_eq:
   \<open>concat_bit n k l = take_bit n k + push_bit n l\<close>
   by (simp add: concat_bit_def take_bit_eq_mask
     bit_and_iff bit_mask_iff bit_push_bit_iff disjunctive_add)
 
 lemma concat_bit_0 [simp]:
   \<open>concat_bit 0 k l = l\<close>
   by (simp add: concat_bit_def)
 
 lemma concat_bit_Suc:
   \<open>concat_bit (Suc n) k l = k mod 2 + 2 * concat_bit n (k div 2) l\<close>
   by (simp add: concat_bit_eq take_bit_Suc push_bit_double)
 
 lemma concat_bit_of_zero_1 [simp]:
   \<open>concat_bit n 0 l = push_bit n l\<close>
   by (simp add: concat_bit_def)
 
 lemma concat_bit_of_zero_2 [simp]:
   \<open>concat_bit n k 0 = take_bit n k\<close>
   by (simp add: concat_bit_def take_bit_eq_mask)
 
 lemma concat_bit_nonnegative_iff [simp]:
   \<open>concat_bit n k l \<ge> 0 \<longleftrightarrow> l \<ge> 0\<close>
   by (simp add: concat_bit_def)
 
 lemma concat_bit_negative_iff [simp]:
   \<open>concat_bit n k l < 0 \<longleftrightarrow> l < 0\<close>
   by (simp add: concat_bit_def)
 
 lemma concat_bit_assoc:
   \<open>concat_bit n k (concat_bit m l r) = concat_bit (m + n) (concat_bit n k l) r\<close>
   by (rule bit_eqI) (auto simp add: bit_concat_bit_iff ac_simps)
 
 lemma concat_bit_assoc_sym:
   \<open>concat_bit m (concat_bit n k l) r = concat_bit (min m n) k (concat_bit (m - n) l r)\<close>
   by (rule bit_eqI) (auto simp add: bit_concat_bit_iff ac_simps min_def)
 
 lemma concat_bit_eq_iff:
   \<open>concat_bit n k l = concat_bit n r s
     \<longleftrightarrow> take_bit n k = take_bit n r \<and> l = s\<close> (is \<open>?P \<longleftrightarrow> ?Q\<close>)
 proof
   assume ?Q
   then show ?P
     by (simp add: concat_bit_def)
 next
   assume ?P
   then have *: \<open>bit (concat_bit n k l) m = bit (concat_bit n r s) m\<close> for m
     by (simp add: bit_eq_iff)
   have \<open>take_bit n k = take_bit n r\<close>
   proof (rule bit_eqI)
     fix m
     from * [of m]
     show \<open>bit (take_bit n k) m \<longleftrightarrow> bit (take_bit n r) m\<close>
       by (auto simp add: bit_take_bit_iff bit_concat_bit_iff)
   qed
   moreover have \<open>push_bit n l = push_bit n s\<close>
   proof (rule bit_eqI)
     fix m
     from * [of m]
     show \<open>bit (push_bit n l) m \<longleftrightarrow> bit (push_bit n s) m\<close>
       by (auto simp add: bit_push_bit_iff bit_concat_bit_iff)
   qed
   then have \<open>l = s\<close>
     by (simp add: push_bit_eq_mult)
   ultimately show ?Q
     by (simp add: concat_bit_def)
 qed
 
 lemma take_bit_concat_bit_eq:
   \<open>take_bit m (concat_bit n k l) = concat_bit (min m n) k (take_bit (m - n) l)\<close>
   by (rule bit_eqI)
-    (auto simp add: bit_take_bit_iff bit_concat_bit_iff min_def)  
+    (auto simp add: bit_take_bit_iff bit_concat_bit_iff min_def)
 
 lemma concat_bit_take_bit_eq:
   \<open>concat_bit n (take_bit n b) = concat_bit n b\<close>
   by (simp add: concat_bit_def [abs_def])
 
 
 subsection \<open>Taking bits with sign propagation\<close>
 
 context ring_bit_operations
 begin
 
 definition signed_take_bit :: \<open>nat \<Rightarrow> 'a \<Rightarrow> 'a\<close>
   where \<open>signed_take_bit n a = take_bit n a OR (of_bool (bit a n) * NOT (mask n))\<close>
 
 lemma signed_take_bit_eq_if_positive:
   \<open>signed_take_bit n a = take_bit n a\<close> if \<open>\<not> bit a n\<close>
   using that by (simp add: signed_take_bit_def)
 
 lemma signed_take_bit_eq_if_negative:
   \<open>signed_take_bit n a = take_bit n a OR NOT (mask n)\<close> if \<open>bit a n\<close>
   using that by (simp add: signed_take_bit_def)
 
 lemma even_signed_take_bit_iff:
   \<open>even (signed_take_bit m a) \<longleftrightarrow> even a\<close>
   by (auto simp add: bit_0 signed_take_bit_def even_or_iff even_mask_iff bit_double_iff)
 
 lemma bit_signed_take_bit_iff [bit_simps]:
   \<open>bit (signed_take_bit m a) n \<longleftrightarrow> possible_bit TYPE('a) n \<and> bit a (min m n)\<close>
   by (simp add: signed_take_bit_def bit_take_bit_iff bit_or_iff bit_not_iff bit_mask_iff min_def not_le)
     (blast dest: bit_imp_possible_bit)
 
 lemma signed_take_bit_0 [simp]:
   \<open>signed_take_bit 0 a = - (a mod 2)\<close>
   by (simp add: bit_0 signed_take_bit_def odd_iff_mod_2_eq_one)
 
 lemma signed_take_bit_Suc:
   \<open>signed_take_bit (Suc n) a = a mod 2 + 2 * signed_take_bit n (a div 2)\<close>
   by (simp add: bit_eq_iff bit_sum_mult_2_cases bit_simps bit_0 possible_bit_less_imp flip: bit_Suc min_Suc_Suc)
 
 lemma signed_take_bit_of_0 [simp]:
   \<open>signed_take_bit n 0 = 0\<close>
   by (simp add: signed_take_bit_def)
 
 lemma signed_take_bit_of_minus_1 [simp]:
   \<open>signed_take_bit n (- 1) = - 1\<close>
   by (simp add: signed_take_bit_def mask_eq_exp_minus_1 possible_bit_def)
 
 lemma signed_take_bit_Suc_1 [simp]:
   \<open>signed_take_bit (Suc n) 1 = 1\<close>
   by (simp add: signed_take_bit_Suc)
 
 lemma signed_take_bit_numeral_of_1 [simp]:
   \<open>signed_take_bit (numeral k) 1 = 1\<close>
   by (simp add: bit_1_iff signed_take_bit_eq_if_positive)
 
 lemma signed_take_bit_rec:
   \<open>signed_take_bit n a = (if n = 0 then - (a mod 2) else a mod 2 + 2 * signed_take_bit (n - 1) (a div 2))\<close>
   by (cases n) (simp_all add: signed_take_bit_Suc)
 
 lemma signed_take_bit_eq_iff_take_bit_eq:
   \<open>signed_take_bit n a = signed_take_bit n b \<longleftrightarrow> take_bit (Suc n) a = take_bit (Suc n) b\<close>
 proof -
   have \<open>bit (signed_take_bit n a) = bit (signed_take_bit n b) \<longleftrightarrow> bit (take_bit (Suc n) a) = bit (take_bit (Suc n) b)\<close>
     by (simp add: fun_eq_iff bit_signed_take_bit_iff bit_take_bit_iff not_le less_Suc_eq_le min_def)
       (use bit_imp_possible_bit in fastforce)
   then show ?thesis
     by (auto simp add: fun_eq_iff intro: bit_eqI)
 qed
 
 lemma signed_take_bit_signed_take_bit [simp]:
   \<open>signed_take_bit m (signed_take_bit n a) = signed_take_bit (min m n) a\<close>
   by (auto simp add: bit_eq_iff bit_simps ac_simps)
 
 lemma signed_take_bit_take_bit:
   \<open>signed_take_bit m (take_bit n a) = (if n \<le> m then take_bit n else signed_take_bit m) a\<close>
   by (rule bit_eqI) (auto simp add: bit_signed_take_bit_iff min_def bit_take_bit_iff)
 
 lemma take_bit_signed_take_bit:
   \<open>take_bit m (signed_take_bit n a) = take_bit m a\<close> if \<open>m \<le> Suc n\<close>
   using that by (rule le_SucE; intro bit_eqI)
    (auto simp add: bit_take_bit_iff bit_signed_take_bit_iff min_def less_Suc_eq)
 
 end
 
 text \<open>Modulus centered around 0\<close>
 
 lemma signed_take_bit_eq_concat_bit:
   \<open>signed_take_bit n k = concat_bit n k (- of_bool (bit k n))\<close>
   by (simp add: concat_bit_def signed_take_bit_def)
 
 lemma signed_take_bit_add:
   \<open>signed_take_bit n (signed_take_bit n k + signed_take_bit n l) = signed_take_bit n (k + l)\<close>
   for k l :: int
 proof -
   have \<open>take_bit (Suc n)
      (take_bit (Suc n) (signed_take_bit n k) +
       take_bit (Suc n) (signed_take_bit n l)) =
     take_bit (Suc n) (k + l)\<close>
     by (simp add: take_bit_signed_take_bit take_bit_add)
   then show ?thesis
     by (simp only: signed_take_bit_eq_iff_take_bit_eq take_bit_add)
 qed
 
 lemma signed_take_bit_diff:
   \<open>signed_take_bit n (signed_take_bit n k - signed_take_bit n l) = signed_take_bit n (k - l)\<close>
   for k l :: int
 proof -
   have \<open>take_bit (Suc n)
      (take_bit (Suc n) (signed_take_bit n k) -
       take_bit (Suc n) (signed_take_bit n l)) =
     take_bit (Suc n) (k - l)\<close>
     by (simp add: take_bit_signed_take_bit take_bit_diff)
   then show ?thesis
     by (simp only: signed_take_bit_eq_iff_take_bit_eq take_bit_diff)
 qed
 
 lemma signed_take_bit_minus:
   \<open>signed_take_bit n (- signed_take_bit n k) = signed_take_bit n (- k)\<close>
   for k :: int
 proof -
   have \<open>take_bit (Suc n)
      (- take_bit (Suc n) (signed_take_bit n k)) =
     take_bit (Suc n) (- k)\<close>
     by (simp add: take_bit_signed_take_bit take_bit_minus)
   then show ?thesis
     by (simp only: signed_take_bit_eq_iff_take_bit_eq take_bit_minus)
 qed
 
 lemma signed_take_bit_mult:
   \<open>signed_take_bit n (signed_take_bit n k * signed_take_bit n l) = signed_take_bit n (k * l)\<close>
   for k l :: int
 proof -
   have \<open>take_bit (Suc n)
      (take_bit (Suc n) (signed_take_bit n k) *
       take_bit (Suc n) (signed_take_bit n l)) =
     take_bit (Suc n) (k * l)\<close>
     by (simp add: take_bit_signed_take_bit take_bit_mult)
   then show ?thesis
     by (simp only: signed_take_bit_eq_iff_take_bit_eq take_bit_mult)
 qed
 
 lemma signed_take_bit_eq_take_bit_minus:
   \<open>signed_take_bit n k = take_bit (Suc n) k - 2 ^ Suc n * of_bool (bit k n)\<close>
   for k :: int
 proof (cases \<open>bit k n\<close>)
   case True
   have \<open>signed_take_bit n k = take_bit (Suc n) k OR NOT (mask (Suc n))\<close>
     by (rule bit_eqI) (auto simp add: bit_signed_take_bit_iff min_def bit_take_bit_iff bit_or_iff bit_not_iff bit_mask_iff less_Suc_eq True)
   then have \<open>signed_take_bit n k = take_bit (Suc n) k + NOT (mask (Suc n))\<close>
     by (simp add: disjunctive_add bit_take_bit_iff bit_not_iff bit_mask_iff)
   with True show ?thesis
     by (simp flip: minus_exp_eq_not_mask)
 next
   case False
   show ?thesis
     by (rule bit_eqI) (simp add: False bit_signed_take_bit_iff bit_take_bit_iff min_def less_Suc_eq)
 qed
 
 lemma signed_take_bit_eq_take_bit_shift:
   \<open>signed_take_bit n k = take_bit (Suc n) (k + 2 ^ n) - 2 ^ n\<close>
   for k :: int
 proof -
   have *: \<open>take_bit n k OR 2 ^ n = take_bit n k + 2 ^ n\<close>
     by (simp add: disjunctive_add bit_exp_iff bit_take_bit_iff)
   have \<open>take_bit n k - 2 ^ n = take_bit n k + NOT (mask n)\<close>
     by (simp add: minus_exp_eq_not_mask)
   also have \<open>\<dots> = take_bit n k OR NOT (mask n)\<close>
     by (rule disjunctive_add)
       (simp add: bit_exp_iff bit_take_bit_iff bit_not_iff bit_mask_iff)
   finally have **: \<open>take_bit n k - 2 ^ n = take_bit n k OR NOT (mask n)\<close> .
   have \<open>take_bit (Suc n) (k + 2 ^ n) = take_bit (Suc n) (take_bit (Suc n) k + take_bit (Suc n) (2 ^ n))\<close>
     by (simp only: take_bit_add)
   also have \<open>take_bit (Suc n) k = 2 ^ n * of_bool (bit k n) + take_bit n k\<close>
     by (simp add: take_bit_Suc_from_most)
   finally have \<open>take_bit (Suc n) (k + 2 ^ n) = take_bit (Suc n) (2 ^ (n + of_bool (bit k n)) + take_bit n k)\<close>
     by (simp add: ac_simps)
   also have \<open>2 ^ (n + of_bool (bit k n)) + take_bit n k = 2 ^ (n + of_bool (bit k n)) OR take_bit n k\<close>
     by (rule disjunctive_add)
       (auto simp add: disjunctive_add bit_take_bit_iff bit_double_iff bit_exp_iff)
   finally show ?thesis
     using * ** by (simp add: signed_take_bit_def concat_bit_Suc min_def ac_simps)
 qed
 
 lemma signed_take_bit_nonnegative_iff [simp]:
   \<open>0 \<le> signed_take_bit n k \<longleftrightarrow> \<not> bit k n\<close>
   for k :: int
   by (simp add: signed_take_bit_def not_less concat_bit_def)
 
 lemma signed_take_bit_negative_iff [simp]:
   \<open>signed_take_bit n k < 0 \<longleftrightarrow> bit k n\<close>
   for k :: int
   by (simp add: signed_take_bit_def not_less concat_bit_def)
 
 lemma signed_take_bit_int_greater_eq_minus_exp [simp]:
   \<open>- (2 ^ n) \<le> signed_take_bit n k\<close>
   for k :: int
   by (simp add: signed_take_bit_eq_take_bit_shift)
 
 lemma signed_take_bit_int_less_exp [simp]:
   \<open>signed_take_bit n k < 2 ^ n\<close>
   for k :: int
   using take_bit_int_less_exp [of \<open>Suc n\<close>]
   by (simp add: signed_take_bit_eq_take_bit_shift)
 
 lemma signed_take_bit_int_eq_self_iff:
   \<open>signed_take_bit n k = k \<longleftrightarrow> - (2 ^ n) \<le> k \<and> k < 2 ^ n\<close>
   for k :: int
   by (auto simp add: signed_take_bit_eq_take_bit_shift take_bit_int_eq_self_iff algebra_simps)
 
 lemma signed_take_bit_int_eq_self:
   \<open>signed_take_bit n k = k\<close> if \<open>- (2 ^ n) \<le> k\<close> \<open>k < 2 ^ n\<close>
   for k :: int
   using that by (simp add: signed_take_bit_int_eq_self_iff)
 
 lemma signed_take_bit_int_less_eq_self_iff:
   \<open>signed_take_bit n k \<le> k \<longleftrightarrow> - (2 ^ n) \<le> k\<close>
   for k :: int
   by (simp add: signed_take_bit_eq_take_bit_shift take_bit_int_less_eq_self_iff algebra_simps)
     linarith
 
 lemma signed_take_bit_int_less_self_iff:
   \<open>signed_take_bit n k < k \<longleftrightarrow> 2 ^ n \<le> k\<close>
   for k :: int
   by (simp add: signed_take_bit_eq_take_bit_shift take_bit_int_less_self_iff algebra_simps)
 
 lemma signed_take_bit_int_greater_self_iff:
   \<open>k < signed_take_bit n k \<longleftrightarrow> k < - (2 ^ n)\<close>
   for k :: int
   by (simp add: signed_take_bit_eq_take_bit_shift take_bit_int_greater_self_iff algebra_simps)
     linarith
 
 lemma signed_take_bit_int_greater_eq_self_iff:
   \<open>k \<le> signed_take_bit n k \<longleftrightarrow> k < 2 ^ n\<close>
   for k :: int
   by (simp add: signed_take_bit_eq_take_bit_shift take_bit_int_greater_eq_self_iff algebra_simps)
 
 lemma signed_take_bit_int_greater_eq:
   \<open>k + 2 ^ Suc n \<le> signed_take_bit n k\<close> if \<open>k < - (2 ^ n)\<close>
   for k :: int
   using that take_bit_int_greater_eq [of \<open>k + 2 ^ n\<close> \<open>Suc n\<close>]
   by (simp add: signed_take_bit_eq_take_bit_shift)
 
 lemma signed_take_bit_int_less_eq:
   \<open>signed_take_bit n k \<le> k - 2 ^ Suc n\<close> if \<open>k \<ge> 2 ^ n\<close>
   for k :: int
   using that take_bit_int_less_eq [of \<open>Suc n\<close> \<open>k + 2 ^ n\<close>]
   by (simp add: signed_take_bit_eq_take_bit_shift)
 
 lemma signed_take_bit_Suc_bit0 [simp]:
   \<open>signed_take_bit (Suc n) (numeral (Num.Bit0 k)) = signed_take_bit n (numeral k) * (2 :: int)\<close>
   by (simp add: signed_take_bit_Suc)
 
 lemma signed_take_bit_Suc_bit1 [simp]:
   \<open>signed_take_bit (Suc n) (numeral (Num.Bit1 k)) = signed_take_bit n (numeral k) * 2 + (1 :: int)\<close>
   by (simp add: signed_take_bit_Suc)
 
 lemma signed_take_bit_Suc_minus_bit0 [simp]:
   \<open>signed_take_bit (Suc n) (- numeral (Num.Bit0 k)) = signed_take_bit n (- numeral k) * (2 :: int)\<close>
   by (simp add: signed_take_bit_Suc)
 
 lemma signed_take_bit_Suc_minus_bit1 [simp]:
   \<open>signed_take_bit (Suc n) (- numeral (Num.Bit1 k)) = signed_take_bit n (- numeral k - 1) * 2 + (1 :: int)\<close>
   by (simp add: signed_take_bit_Suc)
 
 lemma signed_take_bit_numeral_bit0 [simp]:
   \<open>signed_take_bit (numeral l) (numeral (Num.Bit0 k)) = signed_take_bit (pred_numeral l) (numeral k) * (2 :: int)\<close>
   by (simp add: signed_take_bit_rec)
 
 lemma signed_take_bit_numeral_bit1 [simp]:
   \<open>signed_take_bit (numeral l) (numeral (Num.Bit1 k)) = signed_take_bit (pred_numeral l) (numeral k) * 2 + (1 :: int)\<close>
   by (simp add: signed_take_bit_rec)
 
 lemma signed_take_bit_numeral_minus_bit0 [simp]:
   \<open>signed_take_bit (numeral l) (- numeral (Num.Bit0 k)) = signed_take_bit (pred_numeral l) (- numeral k) * (2 :: int)\<close>
   by (simp add: signed_take_bit_rec)
 
 lemma signed_take_bit_numeral_minus_bit1 [simp]:
   \<open>signed_take_bit (numeral l) (- numeral (Num.Bit1 k)) = signed_take_bit (pred_numeral l) (- numeral k - 1) * 2 + (1 :: int)\<close>
   by (simp add: signed_take_bit_rec)
 
 lemma signed_take_bit_code [code]:
   \<open>signed_take_bit n a =
   (let l = take_bit (Suc n) a
    in if bit l n then l + push_bit (Suc n) (- 1) else l)\<close>
 proof -
   have *: \<open>take_bit (Suc n) a + push_bit n (- 2) =
     take_bit (Suc n) a OR NOT (mask (Suc n))\<close>
     by (auto simp add: bit_take_bit_iff bit_push_bit_iff bit_not_iff bit_mask_iff disjunctive_add
        simp flip: push_bit_minus_one_eq_not_mask)
   show ?thesis
     by (rule bit_eqI)
       (auto simp add: Let_def * bit_signed_take_bit_iff bit_take_bit_iff min_def less_Suc_eq bit_not_iff
         bit_mask_iff bit_or_iff simp del: push_bit_minus_one_eq_not_mask)
 qed
 
 
 subsection \<open>Symbolic computations for code generation\<close>
 
 lemma bit_int_code [code]:
   \<open>bit (0::int)               n      \<longleftrightarrow> False\<close>
   \<open>bit (Int.Neg num.One)      n      \<longleftrightarrow> True\<close>
   \<open>bit (Int.Pos num.One)      0      \<longleftrightarrow> True\<close>
   \<open>bit (Int.Pos (num.Bit0 m)) 0      \<longleftrightarrow> False\<close>
   \<open>bit (Int.Pos (num.Bit1 m)) 0      \<longleftrightarrow> True\<close>
   \<open>bit (Int.Neg (num.Bit0 m)) 0      \<longleftrightarrow> False\<close>
   \<open>bit (Int.Neg (num.Bit1 m)) 0      \<longleftrightarrow> True\<close>
   \<open>bit (Int.Pos num.One)      (Suc n) \<longleftrightarrow> False\<close>
   \<open>bit (Int.Pos (num.Bit0 m)) (Suc n) \<longleftrightarrow> bit (Int.Pos m) n\<close>
   \<open>bit (Int.Pos (num.Bit1 m)) (Suc n) \<longleftrightarrow> bit (Int.Pos m) n\<close>
   \<open>bit (Int.Neg (num.Bit0 m)) (Suc n) \<longleftrightarrow> bit (Int.Neg m) n\<close>
   \<open>bit (Int.Neg (num.Bit1 m)) (Suc n) \<longleftrightarrow> bit (Int.Neg (Num.inc m)) n\<close>
   by (simp_all add: Num.add_One bit_0 bit_Suc)
 
 lemma not_int_code [code]:
   \<open>NOT (0 :: int) = - 1\<close>
   \<open>NOT (Int.Pos n) = Int.Neg (Num.inc n)\<close>
   \<open>NOT (Int.Neg n) = Num.sub n num.One\<close>
   by (simp_all add: Num.add_One not_int_def)
 
 lemma and_int_code [code]:
   fixes i j :: int shows
   \<open>0 AND j = 0\<close>
   \<open>i AND 0 = 0\<close>
   \<open>Int.Pos n AND Int.Pos m = (case and_num n m of None \<Rightarrow> 0 | Some n' \<Rightarrow> Int.Pos n')\<close>
   \<open>Int.Neg n AND Int.Neg m = NOT (Num.sub n num.One OR Num.sub m num.One)\<close>
   \<open>Int.Pos n AND Int.Neg num.One = Int.Pos n\<close>
   \<open>Int.Pos n AND Int.Neg (num.Bit0 m) = Num.sub (or_not_num_neg (Num.BitM m) n) num.One\<close>
   \<open>Int.Pos n AND Int.Neg (num.Bit1 m) = Num.sub (or_not_num_neg (num.Bit0 m) n) num.One\<close>
   \<open>Int.Neg num.One AND Int.Pos m = Int.Pos m\<close>
   \<open>Int.Neg (num.Bit0 n) AND Int.Pos m = Num.sub (or_not_num_neg (Num.BitM n) m) num.One\<close>
   \<open>Int.Neg (num.Bit1 n) AND Int.Pos m = Num.sub (or_not_num_neg (num.Bit0 n) m) num.One\<close>
   apply (auto simp add: and_num_eq_None_iff [where ?'a = int] and_num_eq_Some_iff [where ?'a = int]
     split: option.split)
      apply (simp_all only: sub_one_eq_not_neg numeral_or_not_num_eq minus_minus and_not_numerals
        bit.de_Morgan_disj bit.double_compl and_not_num_eq_None_iff and_not_num_eq_Some_iff ac_simps)
   done
 
 lemma or_int_code [code]:
   fixes i j :: int shows
   \<open>0 OR j = j\<close>
   \<open>i OR 0 = i\<close>
   \<open>Int.Pos n OR Int.Pos m = Int.Pos (or_num n m)\<close>
   \<open>Int.Neg n OR Int.Neg m = NOT (Num.sub n num.One AND Num.sub m num.One)\<close>
   \<open>Int.Pos n OR Int.Neg num.One = Int.Neg num.One\<close>
   \<open>Int.Pos n OR Int.Neg (num.Bit0 m) = (case and_not_num (Num.BitM m) n of None \<Rightarrow> -1 | Some n' \<Rightarrow> Int.Neg (Num.inc n'))\<close>
   \<open>Int.Pos n OR Int.Neg (num.Bit1 m) = (case and_not_num (num.Bit0 m) n of None \<Rightarrow> -1 | Some n' \<Rightarrow> Int.Neg (Num.inc n'))\<close>
   \<open>Int.Neg num.One OR Int.Pos m = Int.Neg num.One\<close>
   \<open>Int.Neg (num.Bit0 n) OR Int.Pos m = (case and_not_num (Num.BitM n) m of None \<Rightarrow> -1 | Some n' \<Rightarrow> Int.Neg (Num.inc n'))\<close>
   \<open>Int.Neg (num.Bit1 n) OR Int.Pos m = (case and_not_num (num.Bit0 n) m of None \<Rightarrow> -1 | Some n' \<Rightarrow> Int.Neg (Num.inc n'))\<close>
   apply (auto simp add: numeral_or_num_eq split: option.splits)
          apply (simp_all only: and_not_num_eq_None_iff and_not_num_eq_Some_iff and_not_numerals
            numeral_or_not_num_eq or_eq_not_not_and bit.double_compl ac_simps flip: numeral_eq_iff [where ?'a = int])
          apply simp_all
   done
 
 lemma xor_int_code [code]:
   fixes i j :: int shows
   \<open>0 XOR j = j\<close>
   \<open>i XOR 0 = i\<close>
   \<open>Int.Pos n XOR Int.Pos m = (case xor_num n m of None \<Rightarrow> 0 | Some n' \<Rightarrow> Int.Pos n')\<close>
   \<open>Int.Neg n XOR Int.Neg m = Num.sub n num.One XOR Num.sub m num.One\<close>
   \<open>Int.Neg n XOR Int.Pos m = NOT (Num.sub n num.One XOR Int.Pos m)\<close>
   \<open>Int.Pos n XOR Int.Neg m = NOT (Int.Pos n XOR Num.sub m num.One)\<close>
   by (simp_all add: xor_num_eq_None_iff [where ?'a = int] xor_num_eq_Some_iff [where ?'a = int] split: option.split)
 
 lemma push_bit_int_code [code]:
   \<open>push_bit 0 i = i\<close>
   \<open>push_bit (Suc n) i = push_bit n (Int.dup i)\<close>
   by (simp_all add: ac_simps)
 
 lemma drop_bit_int_code [code]:
   fixes i :: int shows
   \<open>drop_bit 0 i = i\<close>
   \<open>drop_bit (Suc n) 0 = (0 :: int)\<close>
   \<open>drop_bit (Suc n) (Int.Pos num.One) = 0\<close>
   \<open>drop_bit (Suc n) (Int.Pos (num.Bit0 m)) = drop_bit n (Int.Pos m)\<close>
   \<open>drop_bit (Suc n) (Int.Pos (num.Bit1 m)) = drop_bit n (Int.Pos m)\<close>
   \<open>drop_bit (Suc n) (Int.Neg num.One) = - 1\<close>
   \<open>drop_bit (Suc n) (Int.Neg (num.Bit0 m)) = drop_bit n (Int.Neg m)\<close>
   \<open>drop_bit (Suc n) (Int.Neg (num.Bit1 m)) = drop_bit n (Int.Neg (Num.inc m))\<close>
   by (simp_all add: drop_bit_Suc add_One)
 
 
 subsection \<open>Key ideas of bit operations\<close>
 
 text \<open>
   When formalizing bit operations, it is tempting to represent
   bit values as explicit lists over a binary type. This however
   is a bad idea, mainly due to the inherent ambiguities in
   representation concerning repeating leading bits.
 
   Hence this approach avoids such explicit lists altogether
   following an algebraic path:
 
   \<^item> Bit values are represented by numeric types: idealized
     unbounded bit values can be represented by type \<^typ>\<open>int\<close>,
     bounded bit values by quotient types over \<^typ>\<open>int\<close>.
 
   \<^item> (A special case are idealized unbounded bit values ending
     in @{term [source] 0} which can be represented by type \<^typ>\<open>nat\<close> but
     only support a restricted set of operations).
 
   \<^item> From this idea follows that
 
       \<^item> multiplication by \<^term>\<open>2 :: int\<close> is a bit shift to the left and
 
       \<^item> division by \<^term>\<open>2 :: int\<close> is a bit shift to the right.
 
   \<^item> Concerning bounded bit values, iterated shifts to the left
     may result in eliminating all bits by shifting them all
     beyond the boundary.  The property \<^prop>\<open>(2 :: int) ^ n \<noteq> 0\<close>
     represents that \<^term>\<open>n\<close> is \<^emph>\<open>not\<close> beyond that boundary.
 
   \<^item> The projection on a single bit is then @{thm bit_iff_odd [where ?'a = int, no_vars]}.
 
   \<^item> This leads to the most fundamental properties of bit values:
 
       \<^item> Equality rule: @{thm bit_eqI [where ?'a = int, no_vars]}
 
       \<^item> Induction rule: @{thm bits_induct [where ?'a = int, no_vars]}
 
   \<^item> Typical operations are characterized as follows:
 
       \<^item> Singleton \<^term>\<open>n\<close>th bit: \<^term>\<open>(2 :: int) ^ n\<close>
 
       \<^item> Bit mask upto bit \<^term>\<open>n\<close>: @{thm mask_eq_exp_minus_1 [where ?'a = int, no_vars]}
 
       \<^item> Left shift: @{thm push_bit_eq_mult [where ?'a = int, no_vars]}
 
       \<^item> Right shift: @{thm drop_bit_eq_div [where ?'a = int, no_vars]}
 
       \<^item> Truncation: @{thm take_bit_eq_mod [where ?'a = int, no_vars]}
 
       \<^item> Negation: @{thm bit_not_iff [where ?'a = int, no_vars]}
 
       \<^item> And: @{thm bit_and_iff [where ?'a = int, no_vars]}
 
       \<^item> Or: @{thm bit_or_iff [where ?'a = int, no_vars]}
 
       \<^item> Xor: @{thm bit_xor_iff [where ?'a = int, no_vars]}
 
-      \<^item> Set a single bit: @{thm set_bit_def [where ?'a = int, no_vars]}
-
-      \<^item> Unset a single bit: @{thm unset_bit_def [where ?'a = int, no_vars]}
-
-      \<^item> Flip a single bit: @{thm flip_bit_def [where ?'a = int, no_vars]}
+      \<^item> Set a single bit: @{thm set_bit_eq_or [where ?'a = int, no_vars]}
+
+      \<^item> Unset a single bit: @{thm unset_bit_eq_and_not [where ?'a = int, no_vars]}
+
+      \<^item> Flip a single bit: @{thm flip_bit_eq_xor [where ?'a = int, no_vars]}
 
       \<^item> Signed truncation, or modulus centered around \<^term>\<open>0::int\<close>: @{thm signed_take_bit_def [no_vars]}
 
       \<^item> Bit concatenation: @{thm concat_bit_def [no_vars]}
 
       \<^item> (Bounded) conversion from and to a list of bits: @{thm horner_sum_bit_eq_take_bit [where ?'a = int, no_vars]}
 \<close>
 
+
+subsection \<open>Lemma duplicates and other\<close>
+
+lemmas set_bit_def = set_bit_eq_or
+
+lemmas unset_bit_def = unset_bit_eq_and_not
+
+lemmas flip_bit_def = flip_bit_eq_xor
+
+lemmas and_int_rec = and_int.rec
+
+lemmas bit_and_int_iff = and_int.bit_iff
+
+lemmas or_int_rec = or_int.rec
+
+lemmas bit_or_int_iff = or_int.bit_iff
+
+lemmas xor_int_rec = xor_int.rec
+
+lemmas bit_xor_int_iff = xor_int.bit_iff
+
+lemma not_int_rec:
+  \<open>NOT k = of_bool (even k) + 2 * NOT (k div 2)\<close> for k :: int
+  by (fact not_rec)
+
+lemma even_not_iff_int:
+  \<open>even (NOT k) \<longleftrightarrow> odd k\<close> for k :: int
+  by (fact even_not_iff)
+
+lemma even_and_iff_int:
+  \<open>even (k AND l) \<longleftrightarrow> even k \<or> even l\<close> for k l :: int
+  by (fact even_and_iff)
+
 no_notation
   not  (\<open>NOT\<close>)
     and "and"  (infixr \<open>AND\<close> 64)
     and or  (infixr \<open>OR\<close>  59)
     and xor  (infixr \<open>XOR\<close> 59)
 
 bundle bit_operations_syntax
 begin
 
 notation
   not  (\<open>NOT\<close>)
     and "and"  (infixr \<open>AND\<close> 64)
     and or  (infixr \<open>OR\<close>  59)
     and xor  (infixr \<open>XOR\<close> 59)
 
 end
 
 end