--- a/NEWS Wed May 12 17:05:28 2021 +0000
+++ b/NEWS Wed May 12 17:05:29 2021 +0000
@@ -100,6 +100,9 @@
in separate theory "Transposition" in HOL-Combinatorics.
INCOMPATIBILITY.
+* Bit operations set_bit, unset_bit and flip_bit are now class
+operations. INCOMPATIBILITY.
+
*** ML ***
--- a/src/HOL/Library/Bit_Operations.thy Wed May 12 17:05:28 2021 +0000
+++ b/src/HOL/Library/Bit_Operations.thy Wed May 12 17:05:29 2021 +0000
@@ -16,10 +16,16 @@
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>
- assumes bit_and_iff [bit_simps]: \<open>\<And>n. bit (a AND b) n \<longleftrightarrow> bit a n \<and> bit b n\<close>
- and bit_or_iff [bit_simps]: \<open>\<And>n. bit (a OR b) n \<longleftrightarrow> bit a n \<or> bit b n\<close>
- and bit_xor_iff [bit_simps]: \<open>\<And>n. bit (a XOR b) n \<longleftrightarrow> bit a n \<noteq> bit b n\<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>
+ assumes bit_and_iff [bit_simps]: \<open>bit (a AND b) n \<longleftrightarrow> bit a n \<and> bit b n\<close>
+ and bit_or_iff [bit_simps]: \<open>bit (a OR b) n \<longleftrightarrow> bit a n \<or> bit b n\<close>
+ and bit_xor_iff [bit_simps]: \<open>bit (a XOR b) n \<longleftrightarrow> bit a n \<noteq> bit b n\<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 bit_unset_bit_iff [bit_simps]: \<open>bit (unset_bit m a) n \<longleftrightarrow> bit a n \<and> m \<noteq> n\<close>
+ and flip_bit_eq_xor: \<open>flip_bit n a = a XOR push_bit n 1\<close>
begin
text \<open>
@@ -182,6 +188,138 @@
apply (simp_all add: bit_exp_iff)
done
+lemmas set_bit_def = set_bit_eq_or
+
+lemma bit_set_bit_iff [bit_simps]:
+ \<open>bit (set_bit m a) n \<longleftrightarrow> bit a n \<or> (m = n \<and> 2 ^ n \<noteq> 0)\<close>
+ by (auto simp add: set_bit_def push_bit_of_1 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
+
+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
+
+lemmas flip_bit_def = flip_bit_eq_xor
+
+lemma bit_flip_bit_iff [bit_simps]:
+ \<open>bit (flip_bit m a) n \<longleftrightarrow> (m = n \<longleftrightarrow> \<not> bit a n) \<and> 2 ^ n \<noteq> 0\<close>
+ by (auto simp add: flip_bit_def push_bit_of_1 bit_xor_iff bit_exp_iff exp_eq_0_imp_not_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
+
+lemma set_bit_0 [simp]:
+ \<open>set_bit 0 a = 1 + 2 * (a div 2)\<close>
+proof (rule bit_eqI)
+ fix m
+ assume *: \<open>2 ^ m \<noteq> 0\<close>
+ then show \<open>bit (set_bit 0 a) m = bit (1 + 2 * (a div 2)) m\<close>
+ by (simp add: bit_set_bit_iff bit_double_iff even_bit_succ_iff)
+ (cases m, simp_all add: bit_Suc)
+qed
+
+lemma set_bit_Suc:
+ \<open>set_bit (Suc n) a = a mod 2 + 2 * set_bit n (a div 2)\<close>
+proof (rule bit_eqI)
+ fix m
+ assume *: \<open>2 ^ m \<noteq> 0\<close>
+ show \<open>bit (set_bit (Suc n) a) m \<longleftrightarrow> bit (a mod 2 + 2 * set_bit n (a div 2)) m\<close>
+ proof (cases m)
+ case 0
+ then show ?thesis
+ by (simp add: even_set_bit_iff)
+ next
+ case (Suc m)
+ with * have \<open>2 ^ m \<noteq> 0\<close>
+ using mult_2 by auto
+ show ?thesis
+ by (cases a rule: parity_cases)
+ (simp_all add: bit_set_bit_iff bit_double_iff even_bit_succ_iff *,
+ simp_all add: Suc \<open>2 ^ m \<noteq> 0\<close> bit_Suc)
+ qed
+qed
+
+lemma unset_bit_0 [simp]:
+ \<open>unset_bit 0 a = 2 * (a div 2)\<close>
+proof (rule bit_eqI)
+ fix m
+ assume *: \<open>2 ^ m \<noteq> 0\<close>
+ then show \<open>bit (unset_bit 0 a) m = bit (2 * (a div 2)) m\<close>
+ by (simp add: bit_unset_bit_iff bit_double_iff)
+ (cases m, simp_all add: bit_Suc)
+qed
+
+lemma unset_bit_Suc:
+ \<open>unset_bit (Suc n) a = a mod 2 + 2 * unset_bit n (a div 2)\<close>
+proof (rule bit_eqI)
+ fix m
+ assume *: \<open>2 ^ m \<noteq> 0\<close>
+ then show \<open>bit (unset_bit (Suc n) a) m \<longleftrightarrow> bit (a mod 2 + 2 * unset_bit n (a div 2)) m\<close>
+ proof (cases m)
+ case 0
+ then show ?thesis
+ by (simp add: even_unset_bit_iff)
+ next
+ case (Suc m)
+ show ?thesis
+ by (cases a rule: parity_cases)
+ (simp_all add: bit_unset_bit_iff bit_double_iff even_bit_succ_iff *,
+ simp_all add: Suc bit_Suc)
+ qed
+qed
+
+lemma flip_bit_0 [simp]:
+ \<open>flip_bit 0 a = of_bool (even a) + 2 * (a div 2)\<close>
+proof (rule bit_eqI)
+ fix m
+ assume *: \<open>2 ^ m \<noteq> 0\<close>
+ then show \<open>bit (flip_bit 0 a) m = bit (of_bool (even a) + 2 * (a div 2)) m\<close>
+ by (simp add: bit_flip_bit_iff bit_double_iff even_bit_succ_iff)
+ (cases m, simp_all add: bit_Suc)
+qed
+
+lemma flip_bit_Suc:
+ \<open>flip_bit (Suc n) a = a mod 2 + 2 * flip_bit n (a div 2)\<close>
+proof (rule bit_eqI)
+ fix m
+ assume *: \<open>2 ^ m \<noteq> 0\<close>
+ show \<open>bit (flip_bit (Suc n) a) m \<longleftrightarrow> bit (a mod 2 + 2 * flip_bit n (a div 2)) m\<close>
+ proof (cases m)
+ case 0
+ then show ?thesis
+ by (simp add: even_flip_bit_iff)
+ next
+ case (Suc m)
+ with * have \<open>2 ^ m \<noteq> 0\<close>
+ using mult_2 by auto
+ show ?thesis
+ by (cases a rule: parity_cases)
+ (simp_all add: bit_flip_bit_iff bit_double_iff even_bit_succ_iff,
+ simp_all add: Suc \<open>2 ^ m \<noteq> 0\<close> bit_Suc)
+ qed
+qed
+
+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)
+
+
end
class ring_bit_operations = semiring_bit_operations + ring_parity +
@@ -352,149 +490,11 @@
\<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 take_bit_mask [simp]:
- \<open>take_bit m (mask n) = mask (min m n)\<close>
- by (simp add: mask_eq_take_bit_minus_one)
-
-definition set_bit :: \<open>nat \<Rightarrow> 'a \<Rightarrow> 'a\<close>
- where \<open>set_bit n a = a OR push_bit n 1\<close>
-
-definition unset_bit :: \<open>nat \<Rightarrow> 'a \<Rightarrow> 'a\<close>
- where \<open>unset_bit n a = a AND NOT (push_bit n 1)\<close>
-
-definition flip_bit :: \<open>nat \<Rightarrow> 'a \<Rightarrow> 'a\<close>
- where \<open>flip_bit n a = a XOR push_bit n 1\<close>
-
-lemma bit_set_bit_iff [bit_simps]:
- \<open>bit (set_bit m a) n \<longleftrightarrow> bit a n \<or> (m = n \<and> 2 ^ n \<noteq> 0)\<close>
- by (auto simp add: set_bit_def push_bit_of_1 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
-
-lemma bit_unset_bit_iff [bit_simps]:
- \<open>bit (unset_bit m a) n \<longleftrightarrow> bit a n \<and> m \<noteq> n\<close>
- by (auto simp add: unset_bit_def push_bit_of_1 bit_and_iff bit_not_iff bit_exp_iff exp_eq_0_imp_not_bit)
-
-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
-
-lemma bit_flip_bit_iff [bit_simps]:
- \<open>bit (flip_bit m a) n \<longleftrightarrow> (m = n \<longleftrightarrow> \<not> bit a n) \<and> 2 ^ n \<noteq> 0\<close>
- by (auto simp add: flip_bit_def push_bit_of_1 bit_xor_iff bit_exp_iff exp_eq_0_imp_not_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
-
-lemma set_bit_0 [simp]:
- \<open>set_bit 0 a = 1 + 2 * (a div 2)\<close>
-proof (rule bit_eqI)
- fix m
- assume *: \<open>2 ^ m \<noteq> 0\<close>
- then show \<open>bit (set_bit 0 a) m = bit (1 + 2 * (a div 2)) m\<close>
- by (simp add: bit_set_bit_iff bit_double_iff even_bit_succ_iff)
- (cases m, simp_all add: bit_Suc)
-qed
-
-lemma set_bit_Suc:
- \<open>set_bit (Suc n) a = a mod 2 + 2 * set_bit n (a div 2)\<close>
-proof (rule bit_eqI)
- fix m
- assume *: \<open>2 ^ m \<noteq> 0\<close>
- show \<open>bit (set_bit (Suc n) a) m \<longleftrightarrow> bit (a mod 2 + 2 * set_bit n (a div 2)) m\<close>
- proof (cases m)
- case 0
- then show ?thesis
- by (simp add: even_set_bit_iff)
- next
- case (Suc m)
- with * have \<open>2 ^ m \<noteq> 0\<close>
- using mult_2 by auto
- show ?thesis
- by (cases a rule: parity_cases)
- (simp_all add: bit_set_bit_iff bit_double_iff even_bit_succ_iff *,
- simp_all add: Suc \<open>2 ^ m \<noteq> 0\<close> bit_Suc)
- qed
-qed
+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 unset_bit_0 [simp]:
- \<open>unset_bit 0 a = 2 * (a div 2)\<close>
-proof (rule bit_eqI)
- fix m
- assume *: \<open>2 ^ m \<noteq> 0\<close>
- then show \<open>bit (unset_bit 0 a) m = bit (2 * (a div 2)) m\<close>
- by (simp add: bit_unset_bit_iff bit_double_iff)
- (cases m, simp_all add: bit_Suc)
-qed
-
-lemma unset_bit_Suc:
- \<open>unset_bit (Suc n) a = a mod 2 + 2 * unset_bit n (a div 2)\<close>
-proof (rule bit_eqI)
- fix m
- assume *: \<open>2 ^ m \<noteq> 0\<close>
- then show \<open>bit (unset_bit (Suc n) a) m \<longleftrightarrow> bit (a mod 2 + 2 * unset_bit n (a div 2)) m\<close>
- proof (cases m)
- case 0
- then show ?thesis
- by (simp add: even_unset_bit_iff)
- next
- case (Suc m)
- show ?thesis
- by (cases a rule: parity_cases)
- (simp_all add: bit_unset_bit_iff bit_double_iff even_bit_succ_iff *,
- simp_all add: Suc bit_Suc)
- qed
-qed
-
-lemma flip_bit_0 [simp]:
- \<open>flip_bit 0 a = of_bool (even a) + 2 * (a div 2)\<close>
-proof (rule bit_eqI)
- fix m
- assume *: \<open>2 ^ m \<noteq> 0\<close>
- then show \<open>bit (flip_bit 0 a) m = bit (of_bool (even a) + 2 * (a div 2)) m\<close>
- by (simp add: bit_flip_bit_iff bit_double_iff even_bit_succ_iff)
- (cases m, simp_all add: bit_Suc)
-qed
-
-lemma flip_bit_Suc:
- \<open>flip_bit (Suc n) a = a mod 2 + 2 * flip_bit n (a div 2)\<close>
-proof (rule bit_eqI)
- fix m
- assume *: \<open>2 ^ m \<noteq> 0\<close>
- show \<open>bit (flip_bit (Suc n) a) m \<longleftrightarrow> bit (a mod 2 + 2 * flip_bit n (a div 2)) m\<close>
- proof (cases m)
- case 0
- then show ?thesis
- by (simp add: even_flip_bit_iff)
- next
- case (Suc m)
- with * have \<open>2 ^ m \<noteq> 0\<close>
- using mult_2 by auto
- show ?thesis
- by (cases a rule: parity_cases)
- (simp_all add: bit_flip_bit_iff bit_double_iff even_bit_succ_iff,
- simp_all add: Suc \<open>2 ^ m \<noteq> 0\<close> bit_Suc)
- qed
-qed
-
-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)
+lemmas unset_bit_def = unset_bit_eq_and_not
end
@@ -662,8 +662,17 @@
definition mask_int :: \<open>nat \<Rightarrow> int\<close>
where \<open>mask n = (2 :: int) ^ n - 1\<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
+
instance proof
- fix k l :: int and n :: nat
+ fix k l :: int and m n :: nat
show \<open>- k = NOT (k - 1)\<close>
by (simp add: not_int_def)
show \<open>bit (k AND l) n \<longleftrightarrow> bit k n \<and> bit l n\<close>
@@ -672,7 +681,15 @@
by (fact bit_or_int_iff)
show \<open>bit (k XOR l) n \<longleftrightarrow> bit k n \<noteq> bit l n\<close>
by (fact bit_xor_int_iff)
-qed (simp_all add: bit_not_int_iff mask_int_def)
+ show \<open>bit (unset_bit m k) n \<longleftrightarrow> bit k n \<and> m \<noteq> n\<close>
+ proof -
+ have \<open>unset_bit m k = k AND NOT (push_bit m 1)\<close>
+ by (simp add: unset_bit_int_def)
+ also have \<open>NOT (push_bit m 1 :: int) = - (push_bit m 1 + 1)\<close>
+ by (simp add: not_int_def)
+ finally show ?thesis by (simp only: bit_simps bit_and_int_iff) (auto simp add: bit_simps)
+ qed
+qed (simp_all add: bit_not_int_iff mask_int_def set_bit_int_def flip_bit_int_def)
end
@@ -1592,6 +1609,15 @@
definition mask_nat :: \<open>nat \<Rightarrow> nat\<close>
where \<open>mask n = (2 :: nat) ^ n - 1\<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 = (if bit n m then n - push_bit m 1 else 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 q :: nat
show \<open>bit (m AND n) q \<longleftrightarrow> bit m q \<and> bit n q\<close>
@@ -1600,7 +1626,26 @@
by (simp add: or_nat_def bit_simps)
show \<open>bit (m XOR n) q \<longleftrightarrow> bit m q \<noteq> bit n q\<close>
by (simp add: xor_nat_def bit_simps)
-qed (simp add: mask_nat_def)
+ show \<open>bit (unset_bit m n) q \<longleftrightarrow> bit n q \<and> m \<noteq> q\<close>
+ proof (cases \<open>bit n m\<close>)
+ case False
+ then show ?thesis by (auto simp add: unset_bit_nat_def)
+ next
+ case True
+ have \<open>push_bit m (drop_bit m n) + take_bit m n = n\<close>
+ by (fact bits_ident)
+ also from \<open>bit n m\<close> have \<open>drop_bit m n = 2 * drop_bit (Suc m) n + 1\<close>
+ by (simp add: drop_bit_Suc drop_bit_half even_drop_bit_iff_not_bit ac_simps)
+ finally have \<open>push_bit m (2 * drop_bit (Suc m) n) + take_bit m n + push_bit m 1 = n\<close>
+ by (simp only: push_bit_add ac_simps)
+ then have \<open>n - push_bit m 1 = push_bit m (2 * drop_bit (Suc m) n) + take_bit m n\<close>
+ by simp
+ then have \<open>n - push_bit m 1 = push_bit m (2 * drop_bit (Suc m) n) OR take_bit m n\<close>
+ by (simp add: or_nat_def bit_simps flip: disjunctive_add)
+ with \<open>bit n m\<close> show ?thesis
+ by (auto simp add: unset_bit_nat_def or_nat_def bit_simps)
+ qed
+qed (simp_all add: mask_nat_def set_bit_nat_def flip_bit_nat_def)
end
@@ -1714,9 +1759,19 @@
lift_definition mask_integer :: \<open>nat \<Rightarrow> integer\<close>
is mask .
+lift_definition set_bit_integer :: \<open>nat \<Rightarrow> integer \<Rightarrow> integer\<close>
+ is set_bit .
+
+lift_definition unset_bit_integer :: \<open>nat \<Rightarrow> integer \<Rightarrow> integer\<close>
+ is unset_bit .
+
+lift_definition flip_bit_integer :: \<open>nat \<Rightarrow> integer \<Rightarrow> integer\<close>
+ is flip_bit .
+
instance by (standard; transfer)
(simp_all add: minus_eq_not_minus_1 mask_eq_exp_minus_1
- bit_not_iff bit_and_iff bit_or_iff bit_xor_iff)
+ bit_not_iff bit_and_iff bit_or_iff bit_xor_iff
+ set_bit_def bit_unset_bit_iff flip_bit_def)
end
@@ -1739,8 +1794,19 @@
lift_definition mask_natural :: \<open>nat \<Rightarrow> natural\<close>
is mask .
+lift_definition set_bit_natural :: \<open>nat \<Rightarrow> natural \<Rightarrow> natural\<close>
+ is set_bit .
+
+lift_definition unset_bit_natural :: \<open>nat \<Rightarrow> natural \<Rightarrow> natural\<close>
+ is unset_bit .
+
+lift_definition flip_bit_natural :: \<open>nat \<Rightarrow> natural \<Rightarrow> natural\<close>
+ is flip_bit .
+
instance by (standard; transfer)
- (simp_all add: mask_eq_exp_minus_1 bit_and_iff bit_or_iff bit_xor_iff)
+ (simp_all add: mask_eq_exp_minus_1
+ bit_and_iff bit_or_iff bit_xor_iff
+ set_bit_def bit_unset_bit_iff flip_bit_def)
end
--- a/src/HOL/Library/Word.thy Wed May 12 17:05:28 2021 +0000
+++ b/src/HOL/Library/Word.thy Wed May 12 17:05:29 2021 +0000
@@ -996,9 +996,21 @@
is mask
.
+lift_definition set_bit_word :: \<open>nat \<Rightarrow> 'a word \<Rightarrow> 'a word\<close>
+ is set_bit
+ by (simp add: set_bit_def)
+
+lift_definition unset_bit_word :: \<open>nat \<Rightarrow> 'a word \<Rightarrow> 'a word\<close>
+ is unset_bit
+ by (simp add: unset_bit_def)
+
+lift_definition flip_bit_word :: \<open>nat \<Rightarrow> 'a word \<Rightarrow> 'a word\<close>
+ is flip_bit
+ by (simp add: flip_bit_def)
+
instance by (standard; transfer)
(auto simp add: minus_eq_not_minus_1 mask_eq_exp_minus_1
- bit_not_iff bit_and_iff bit_or_iff bit_xor_iff)
+ bit_simps set_bit_def flip_bit_def)
end
@@ -1027,6 +1039,18 @@
\<open>Word.the_int (mask n :: 'a::len word) = mask (min LENGTH('a) n)\<close>
by transfer simp
+lemma [code]:
+ \<open>set_bit n w = w OR push_bit n 1\<close> for w :: \<open>'a::len word\<close>
+ by (fact set_bit_eq_or)
+
+lemma [code]:
+ \<open>unset_bit n w = w AND NOT (push_bit n 1)\<close> for w :: \<open>'a::len word\<close>
+ by (fact unset_bit_eq_and_not)
+
+lemma [code]:
+ \<open>flip_bit n w = w XOR push_bit n 1\<close> for w :: \<open>'a::len word\<close>
+ by (fact flip_bit_eq_xor)
+
context
includes lifting_syntax
begin
--- a/src/HOL/Library/Z2.thy Wed May 12 17:05:28 2021 +0000
+++ b/src/HOL/Library/Z2.thy Wed May 12 17:05:29 2021 +0000
@@ -188,7 +188,16 @@
where [simp]: \<open>b XOR c = of_bool (odd b \<noteq> odd c)\<close> for b c :: bit
definition mask_bit :: \<open>nat \<Rightarrow> bit\<close>
- where [simp]: \<open>mask_bit n = of_bool (n > 0)\<close>
+ where [simp]: \<open>mask n = (of_bool (n > 0) :: bit)\<close>
+
+definition set_bit_bit :: \<open>nat \<Rightarrow> bit \<Rightarrow> bit\<close>
+ where [simp]: \<open>set_bit n b = of_bool (n = 0 \<or> odd b)\<close> for b :: bit
+
+definition unset_bit_bit :: \<open>nat \<Rightarrow> bit \<Rightarrow> bit\<close>
+ where [simp]: \<open>unset_bit n b = of_bool (n > 0 \<and> odd b)\<close> for b :: bit
+
+definition flip_bit_bit :: \<open>nat \<Rightarrow> bit \<Rightarrow> bit\<close>
+ where [simp]: \<open>flip_bit n b = of_bool ((n = 0) \<noteq> odd b)\<close> for b :: bit
instance
by standard auto