496 lines
16 KiB
Plaintext
496 lines
16 KiB
Plaintext
///////////////////////////////////////////////////////////////
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// Copyright 2012 John Maddock. Distributed under the Boost
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// Software License, Version 1.0. (See accompanying file
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// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_
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#ifndef BOOST_MP_INT_FUNC_HPP
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#define BOOST_MP_INT_FUNC_HPP
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#include <boost/multiprecision/number.hpp>
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namespace boost{ namespace multiprecision{
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namespace default_ops
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{
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template <class Backend>
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inline void eval_qr(const Backend& x, const Backend& y, Backend& q, Backend& r)
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{
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eval_divide(q, x, y);
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eval_modulus(r, x, y);
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}
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template <class Backend, class Integer>
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inline Integer eval_integer_modulus(const Backend& x, Integer val)
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{
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BOOST_MP_USING_ABS
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using default_ops::eval_modulus;
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using default_ops::eval_convert_to;
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typedef typename boost::multiprecision::detail::canonical<Integer, Backend>::type int_type;
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Backend t;
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eval_modulus(t, x, static_cast<int_type>(val));
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Integer result;
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eval_convert_to(&result, t);
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return abs(result);
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}
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#ifdef BOOST_MSVC
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#pragma warning(push)
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#pragma warning(disable:4127)
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#endif
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template <class B>
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inline void eval_gcd(B& result, const B& a, const B& b)
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{
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using default_ops::eval_lsb;
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using default_ops::eval_is_zero;
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using default_ops::eval_get_sign;
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int shift;
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B u(a), v(b);
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int s = eval_get_sign(u);
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/* GCD(0,x) := x */
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if(s < 0)
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{
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u.negate();
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}
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else if(s == 0)
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{
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result = v;
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return;
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}
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s = eval_get_sign(v);
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if(s < 0)
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{
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v.negate();
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}
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else if(s == 0)
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{
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result = u;
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return;
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}
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/* Let shift := lg K, where K is the greatest power of 2
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dividing both u and v. */
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unsigned us = eval_lsb(u);
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unsigned vs = eval_lsb(v);
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shift = (std::min)(us, vs);
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eval_right_shift(u, us);
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eval_right_shift(v, vs);
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do
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{
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/* Now u and v are both odd, so diff(u, v) is even.
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Let u = min(u, v), v = diff(u, v)/2. */
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s = u.compare(v);
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if(s > 0)
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u.swap(v);
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if(s == 0)
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break;
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eval_subtract(v, u);
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vs = eval_lsb(v);
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eval_right_shift(v, vs);
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}
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while(true);
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result = u;
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eval_left_shift(result, shift);
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}
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#ifdef BOOST_MSVC
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#pragma warning(pop)
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#endif
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template <class B>
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inline void eval_lcm(B& result, const B& a, const B& b)
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{
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typedef typename mpl::front<typename B::unsigned_types>::type ui_type;
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B t;
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eval_gcd(t, a, b);
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if(eval_is_zero(t))
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{
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result = static_cast<ui_type>(0);
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}
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else
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{
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eval_divide(result, a, t);
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eval_multiply(result, b);
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}
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if(eval_get_sign(result) < 0)
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result.negate();
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}
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}
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template <class Backend, expression_template_option ExpressionTemplates>
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inline typename enable_if_c<number_category<Backend>::value == number_kind_integer>::type
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divide_qr(const number<Backend, ExpressionTemplates>& x, const number<Backend, ExpressionTemplates>& y,
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number<Backend, ExpressionTemplates>& q, number<Backend, ExpressionTemplates>& r)
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{
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using default_ops::eval_qr;
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eval_qr(x.backend(), y.backend(), q.backend(), r.backend());
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}
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template <class Backend, expression_template_option ExpressionTemplates, class tag, class A1, class A2, class A3, class A4>
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inline typename enable_if_c<number_category<Backend>::value == number_kind_integer>::type
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divide_qr(const number<Backend, ExpressionTemplates>& x, const multiprecision::detail::expression<tag, A1, A2, A3, A4>& y,
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number<Backend, ExpressionTemplates>& q, number<Backend, ExpressionTemplates>& r)
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{
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divide_qr(x, number<Backend, ExpressionTemplates>(y), q, r);
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}
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template <class tag, class A1, class A2, class A3, class A4, class Backend, expression_template_option ExpressionTemplates>
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inline typename enable_if_c<number_category<Backend>::value == number_kind_integer>::type
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divide_qr(const multiprecision::detail::expression<tag, A1, A2, A3, A4>& x, const number<Backend, ExpressionTemplates>& y,
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number<Backend, ExpressionTemplates>& q, number<Backend, ExpressionTemplates>& r)
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{
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divide_qr(number<Backend, ExpressionTemplates>(x), y, q, r);
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}
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template <class tag, class A1, class A2, class A3, class A4, class tagb, class A1b, class A2b, class A3b, class A4b, class Backend, expression_template_option ExpressionTemplates>
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inline typename enable_if_c<number_category<Backend>::value == number_kind_integer>::type
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divide_qr(const multiprecision::detail::expression<tag, A1, A2, A3, A4>& x, const multiprecision::detail::expression<tagb, A1b, A2b, A3b, A4b>& y,
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number<Backend, ExpressionTemplates>& q, number<Backend, ExpressionTemplates>& r)
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{
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divide_qr(number<Backend, ExpressionTemplates>(x), number<Backend, ExpressionTemplates>(y), q, r);
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}
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template <class Backend, expression_template_option ExpressionTemplates, class Integer>
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inline typename enable_if<mpl::and_<is_integral<Integer>, mpl::bool_<number_category<Backend>::value == number_kind_integer> >, Integer>::type
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integer_modulus(const number<Backend, ExpressionTemplates>& x, Integer val)
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{
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using default_ops::eval_integer_modulus;
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return eval_integer_modulus(x.backend(), val);
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}
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template <class tag, class A1, class A2, class A3, class A4, class Integer>
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inline typename enable_if<mpl::and_<is_integral<Integer>, mpl::bool_<number_category<typename multiprecision::detail::expression<tag, A1, A2, A3, A4>::result_type>::value == number_kind_integer> >, Integer>::type
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integer_modulus(const multiprecision::detail::expression<tag, A1, A2, A3, A4>& x, Integer val)
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{
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typedef typename multiprecision::detail::expression<tag, A1, A2, A3, A4>::result_type result_type;
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return integer_modulus(result_type(x), val);
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}
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template <class Backend, expression_template_option ExpressionTemplates>
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inline typename enable_if_c<number_category<Backend>::value == number_kind_integer, unsigned>::type
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lsb(const number<Backend, ExpressionTemplates>& x)
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{
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using default_ops::eval_lsb;
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return eval_lsb(x.backend());
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}
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template <class tag, class A1, class A2, class A3, class A4>
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inline typename enable_if_c<number_category<typename multiprecision::detail::expression<tag, A1, A2, A3, A4>::result_type>::value == number_kind_integer, unsigned>::type
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lsb(const multiprecision::detail::expression<tag, A1, A2, A3, A4>& x)
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{
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typedef typename multiprecision::detail::expression<tag, A1, A2, A3, A4>::result_type number_type;
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number_type n(x);
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using default_ops::eval_lsb;
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return eval_lsb(n.backend());
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}
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template <class Backend, expression_template_option ExpressionTemplates>
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inline typename enable_if_c<number_category<Backend>::value == number_kind_integer, unsigned>::type
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msb(const number<Backend, ExpressionTemplates>& x)
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{
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using default_ops::eval_msb;
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return eval_msb(x.backend());
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}
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template <class tag, class A1, class A2, class A3, class A4>
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inline typename enable_if_c<number_category<typename multiprecision::detail::expression<tag, A1, A2, A3, A4>::result_type>::value == number_kind_integer, unsigned>::type
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msb(const multiprecision::detail::expression<tag, A1, A2, A3, A4>& x)
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{
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typedef typename multiprecision::detail::expression<tag, A1, A2, A3, A4>::result_type number_type;
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number_type n(x);
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using default_ops::eval_msb;
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return eval_msb(n.backend());
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}
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template <class Backend, expression_template_option ExpressionTemplates>
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inline typename enable_if_c<number_category<Backend>::value == number_kind_integer, bool>::type
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bit_test(const number<Backend, ExpressionTemplates>& x, unsigned index)
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{
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using default_ops::eval_bit_test;
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return eval_bit_test(x.backend(), index);
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}
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template <class tag, class A1, class A2, class A3, class A4>
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inline typename enable_if_c<number_category<typename multiprecision::detail::expression<tag, A1, A2, A3, A4>::result_type>::value == number_kind_integer, bool>::type
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bit_test(const multiprecision::detail::expression<tag, A1, A2, A3, A4>& x, unsigned index)
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{
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typedef typename multiprecision::detail::expression<tag, A1, A2, A3, A4>::result_type number_type;
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number_type n(x);
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using default_ops::eval_bit_test;
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return eval_bit_test(n.backend(), index);
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}
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template <class Backend, expression_template_option ExpressionTemplates>
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inline typename enable_if_c<number_category<Backend>::value == number_kind_integer, number<Backend, ExpressionTemplates>&>::type
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bit_set(number<Backend, ExpressionTemplates>& x, unsigned index)
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{
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using default_ops::eval_bit_set;
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eval_bit_set(x.backend(), index);
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return x;
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}
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template <class Backend, expression_template_option ExpressionTemplates>
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inline typename enable_if_c<number_category<Backend>::value == number_kind_integer, number<Backend, ExpressionTemplates>&>::type
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bit_unset(number<Backend, ExpressionTemplates>& x, unsigned index)
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{
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using default_ops::eval_bit_unset;
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eval_bit_unset(x.backend(), index);
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return x;
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}
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template <class Backend, expression_template_option ExpressionTemplates>
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inline typename enable_if_c<number_category<Backend>::value == number_kind_integer, number<Backend, ExpressionTemplates>&>::type
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bit_flip(number<Backend, ExpressionTemplates>& x, unsigned index)
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{
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using default_ops::eval_bit_flip;
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eval_bit_flip(x.backend(), index);
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return x;
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}
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namespace default_ops{
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//
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// Within powm, we need a type with twice as many digits as the argument type, define
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// a traits class to obtain that type:
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//
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template <class Backend>
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struct double_precision_type
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{
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typedef Backend type;
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};
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//
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// If the exponent is a signed integer type, then we need to
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// check the value is positive:
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//
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template <class Backend>
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inline void check_sign_of_backend(const Backend& v, const mpl::true_)
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{
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if(eval_get_sign(v) < 0)
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{
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BOOST_THROW_EXCEPTION(std::runtime_error("powm requires a positive exponent."));
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}
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}
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template <class Backend>
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inline void check_sign_of_backend(const Backend&, const mpl::false_){}
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//
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// Calculate (a^p)%c:
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//
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template <class Backend>
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void eval_powm(Backend& result, const Backend& a, const Backend& p, const Backend& c)
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{
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using default_ops::eval_bit_test;
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using default_ops::eval_get_sign;
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using default_ops::eval_multiply;
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using default_ops::eval_modulus;
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using default_ops::eval_right_shift;
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typedef typename double_precision_type<Backend>::type double_type;
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typedef typename boost::multiprecision::detail::canonical<unsigned char, double_type>::type ui_type;
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check_sign_of_backend(p, mpl::bool_<std::numeric_limits<number<Backend> >::is_signed>());
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double_type x, y(a), b(p), t;
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x = ui_type(1u);
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while(eval_get_sign(b) > 0)
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{
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if(eval_bit_test(b, 0))
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{
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eval_multiply(t, x, y);
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eval_modulus(x, t, c);
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}
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eval_multiply(t, y, y);
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eval_modulus(y, t, c);
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eval_right_shift(b, ui_type(1));
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}
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Backend x2(x);
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eval_modulus(result, x2, c);
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}
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template <class Backend, class Integer>
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void eval_powm(Backend& result, const Backend& a, const Backend& p, Integer c)
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{
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typedef typename double_precision_type<Backend>::type double_type;
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typedef typename boost::multiprecision::detail::canonical<unsigned char, double_type>::type ui_type;
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typedef typename boost::multiprecision::detail::canonical<Integer, double_type>::type i1_type;
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typedef typename boost::multiprecision::detail::canonical<Integer, Backend>::type i2_type;
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using default_ops::eval_bit_test;
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using default_ops::eval_get_sign;
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using default_ops::eval_multiply;
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using default_ops::eval_modulus;
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using default_ops::eval_right_shift;
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check_sign_of_backend(p, mpl::bool_<std::numeric_limits<number<Backend> >::is_signed>());
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if(eval_get_sign(p) < 0)
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{
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BOOST_THROW_EXCEPTION(std::runtime_error("powm requires a positive exponent."));
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}
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double_type x, y(a), b(p), t;
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x = ui_type(1u);
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while(eval_get_sign(b) > 0)
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{
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if(eval_bit_test(b, 0))
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{
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eval_multiply(t, x, y);
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eval_modulus(x, t, static_cast<i1_type>(c));
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}
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eval_multiply(t, y, y);
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eval_modulus(y, t, static_cast<i1_type>(c));
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eval_right_shift(b, ui_type(1));
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}
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Backend x2(x);
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eval_modulus(result, x2, static_cast<i2_type>(c));
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}
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template <class Backend, class Integer>
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typename enable_if<is_unsigned<Integer> >::type eval_powm(Backend& result, const Backend& a, Integer b, const Backend& c)
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{
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typedef typename double_precision_type<Backend>::type double_type;
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typedef typename boost::multiprecision::detail::canonical<unsigned char, double_type>::type ui_type;
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using default_ops::eval_bit_test;
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using default_ops::eval_get_sign;
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using default_ops::eval_multiply;
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using default_ops::eval_modulus;
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using default_ops::eval_right_shift;
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double_type x, y(a), t;
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x = ui_type(1u);
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while(b > 0)
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{
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if(b & 1)
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{
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eval_multiply(t, x, y);
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eval_modulus(x, t, c);
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}
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eval_multiply(t, y, y);
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eval_modulus(y, t, c);
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b >>= 1;
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}
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Backend x2(x);
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eval_modulus(result, x2, c);
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}
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template <class Backend, class Integer>
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typename enable_if<is_signed<Integer> >::type eval_powm(Backend& result, const Backend& a, Integer b, const Backend& c)
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{
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if(b < 0)
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{
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BOOST_THROW_EXCEPTION(std::runtime_error("powm requires a positive exponent."));
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}
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eval_powm(result, a, static_cast<typename make_unsigned<Integer>::type>(b), c);
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}
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template <class Backend, class Integer1, class Integer2>
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typename enable_if<is_unsigned<Integer1> >::type eval_powm(Backend& result, const Backend& a, Integer1 b, Integer2 c)
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{
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typedef typename double_precision_type<Backend>::type double_type;
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typedef typename boost::multiprecision::detail::canonical<unsigned char, double_type>::type ui_type;
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typedef typename boost::multiprecision::detail::canonical<Integer1, double_type>::type i1_type;
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typedef typename boost::multiprecision::detail::canonical<Integer2, Backend>::type i2_type;
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using default_ops::eval_bit_test;
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using default_ops::eval_get_sign;
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using default_ops::eval_multiply;
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using default_ops::eval_modulus;
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using default_ops::eval_right_shift;
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double_type x, y(a), t;
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x = ui_type(1u);
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while(b > 0)
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{
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if(b & 1)
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{
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eval_multiply(t, x, y);
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eval_modulus(x, t, static_cast<i1_type>(c));
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}
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eval_multiply(t, y, y);
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eval_modulus(y, t, static_cast<i1_type>(c));
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b >>= 1;
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}
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Backend x2(x);
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eval_modulus(result, x2, static_cast<i2_type>(c));
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}
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template <class Backend, class Integer1, class Integer2>
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typename enable_if<is_signed<Integer1> >::type eval_powm(Backend& result, const Backend& a, Integer1 b, Integer2 c)
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{
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if(b < 0)
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{
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BOOST_THROW_EXCEPTION(std::runtime_error("powm requires a positive exponent."));
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}
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eval_powm(result, a, static_cast<typename make_unsigned<Integer1>::type>(b), c);
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}
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struct powm_func
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{
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template <class T, class U, class V>
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void operator()(T& result, const T& b, const U& p, const V& m)const
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{
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eval_powm(result, b, p, m);
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}
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};
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}
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template <class T, class U, class V>
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inline typename enable_if<
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mpl::and_<
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mpl::bool_<number_category<T>::value == number_kind_integer>,
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mpl::or_<
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is_number<T>,
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is_number_expression<T>
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>,
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mpl::or_<
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is_number<U>,
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is_number_expression<U>,
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is_integral<U>
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>,
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mpl::or_<
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is_number<V>,
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is_number_expression<V>,
|
|
is_integral<V>
|
|
>
|
|
>,
|
|
typename mpl::if_<
|
|
is_no_et_number<T>,
|
|
T,
|
|
typename mpl::if_<
|
|
is_no_et_number<U>,
|
|
U,
|
|
typename mpl::if_<
|
|
is_no_et_number<V>,
|
|
V,
|
|
detail::expression<detail::function, default_ops::powm_func, T, U, V> >::type
|
|
>::type
|
|
>::type
|
|
>::type
|
|
powm(const T& b, const U& p, const V& mod)
|
|
{
|
|
return detail::expression<detail::function, default_ops::powm_func, T, U, V>(
|
|
default_ops::powm_func(), b, p, mod);
|
|
}
|
|
|
|
}} //namespaces
|
|
|
|
#endif
|
|
|
|
|