///////////////////////////////////////////////////////////////
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// Copyright 2013 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 https://www.boost.org/LICENSE_1_0.txt
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//
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// Comparison operators for cpp_int_backend:
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//
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#ifndef BOOST_MP_DETAIL_BITSCAN_HPP
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#define BOOST_MP_DETAIL_BITSCAN_HPP
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#include <boost/predef/other/endian.h>
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#include <boost/cstdint.hpp>
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#if (defined(BOOST_MSVC) || (defined(__clang__) && defined(__c2__)) || (defined(BOOST_INTEL) && defined(_MSC_VER))) && (defined(_M_IX86) || defined(_M_X64))
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#include <intrin.h>
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#endif
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namespace boost { namespace multiprecision { namespace detail {
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template <class Unsigned>
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inline BOOST_MP_CXX14_CONSTEXPR unsigned find_lsb_default(Unsigned mask)
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{
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unsigned result = 0;
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while (!(mask & 1u))
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{
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mask >>= 1;
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++result;
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}
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return result;
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}
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template <class Unsigned>
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inline BOOST_MP_CXX14_CONSTEXPR unsigned find_msb_default(Unsigned mask)
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{
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unsigned index = 0;
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while (mask)
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{
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++index;
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mask >>= 1;
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}
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return --index;
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}
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template <class Unsigned>
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inline BOOST_MP_CXX14_CONSTEXPR unsigned find_lsb(Unsigned mask, const mpl::int_<0>&)
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{
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return find_lsb_default(mask);
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}
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template <class Unsigned>
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inline BOOST_MP_CXX14_CONSTEXPR unsigned find_msb(Unsigned mask, const mpl::int_<0>&)
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{
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return find_msb_default(mask);
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}
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#if (defined(BOOST_MSVC) || (defined(__clang__) && defined(__c2__)) || (defined(BOOST_INTEL) && defined(_MSC_VER))) && (defined(_M_IX86) || defined(_M_X64))
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#pragma intrinsic(_BitScanForward, _BitScanReverse)
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BOOST_FORCEINLINE unsigned find_lsb(unsigned long mask, const mpl::int_<1>&)
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{
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unsigned long result;
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_BitScanForward(&result, mask);
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return result;
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}
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BOOST_FORCEINLINE unsigned find_msb(unsigned long mask, const mpl::int_<1>&)
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{
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unsigned long result;
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_BitScanReverse(&result, mask);
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return result;
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}
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#ifdef _M_X64
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#pragma intrinsic(_BitScanForward64, _BitScanReverse64)
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BOOST_FORCEINLINE unsigned find_lsb(unsigned __int64 mask, const mpl::int_<2>&)
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{
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unsigned long result;
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_BitScanForward64(&result, mask);
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return result;
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}
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template <class Unsigned>
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BOOST_FORCEINLINE unsigned find_msb(Unsigned mask, const mpl::int_<2>&)
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{
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unsigned long result;
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_BitScanReverse64(&result, mask);
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return result;
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}
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#endif
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template <class Unsigned>
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BOOST_FORCEINLINE BOOST_MP_CXX14_CONSTEXPR unsigned find_lsb(Unsigned mask)
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{
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typedef typename make_unsigned<Unsigned>::type ui_type;
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typedef typename mpl::if_c<
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sizeof(Unsigned) <= sizeof(unsigned long),
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mpl::int_<1>,
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#ifdef _M_X64
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typename mpl::if_c<
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sizeof(Unsigned) <= sizeof(__int64),
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mpl::int_<2>,
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mpl::int_<0> >::type
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#else
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mpl::int_<0>
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#endif
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>::type tag_type;
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#ifndef BOOST_MP_NO_CONSTEXPR_DETECTION
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if (BOOST_MP_IS_CONST_EVALUATED(mask))
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{
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return find_lsb_default(mask);
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}
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else
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#endif
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return find_lsb(static_cast<ui_type>(mask), tag_type());
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}
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template <class Unsigned>
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BOOST_FORCEINLINE BOOST_MP_CXX14_CONSTEXPR unsigned find_msb(Unsigned mask)
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{
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typedef typename make_unsigned<Unsigned>::type ui_type;
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typedef typename mpl::if_c<
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sizeof(Unsigned) <= sizeof(unsigned long),
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mpl::int_<1>,
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#ifdef _M_X64
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typename mpl::if_c<
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sizeof(Unsigned) <= sizeof(__int64),
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mpl::int_<2>,
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mpl::int_<0> >::type
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#else
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mpl::int_<0>
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#endif
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>::type tag_type;
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#ifndef BOOST_MP_NO_CONSTEXPR_DETECTION
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if (BOOST_MP_IS_CONST_EVALUATED(mask))
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{
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return find_msb_default(mask);
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}
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else
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#endif
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return find_msb(static_cast<ui_type>(mask), tag_type());
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}
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#elif defined(BOOST_GCC) || defined(__clang__) || (defined(BOOST_INTEL) && defined(__GNUC__))
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BOOST_FORCEINLINE unsigned find_lsb(unsigned mask, mpl::int_<1> const&)
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{
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return __builtin_ctz(mask);
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}
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BOOST_FORCEINLINE unsigned find_lsb(unsigned long mask, mpl::int_<2> const&)
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{
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return __builtin_ctzl(mask);
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}
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BOOST_FORCEINLINE unsigned find_lsb(boost::ulong_long_type mask, mpl::int_<3> const&)
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{
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return __builtin_ctzll(mask);
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}
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BOOST_FORCEINLINE unsigned find_msb(unsigned mask, mpl::int_<1> const&)
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{
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return sizeof(unsigned) * CHAR_BIT - 1 - __builtin_clz(mask);
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}
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BOOST_FORCEINLINE unsigned find_msb(unsigned long mask, mpl::int_<2> const&)
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{
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return sizeof(unsigned long) * CHAR_BIT - 1 - __builtin_clzl(mask);
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}
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BOOST_FORCEINLINE unsigned find_msb(boost::ulong_long_type mask, mpl::int_<3> const&)
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{
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return sizeof(boost::ulong_long_type) * CHAR_BIT - 1 - __builtin_clzll(mask);
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}
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#ifdef BOOST_HAS_INT128
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__extension__ typedef unsigned __int128 uint128_type;
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BOOST_FORCEINLINE unsigned find_msb(uint128_type mask, mpl::int_<0> const&)
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{
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union
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{
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uint128_type v;
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boost::uint64_t sv[2];
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} val;
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val.v = mask;
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#if BOOST_ENDIAN_LITTLE_BYTE
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if (val.sv[1])
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return find_msb(val.sv[1], mpl::int_<3>()) + 64;
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return find_msb(val.sv[0], mpl::int_<3>());
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#else
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if (val.sv[0])
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return find_msb(val.sv[0], mpl::int_<3>()) + 64;
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return find_msb(val.sv[1], mpl::int_<3>());
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#endif
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}
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BOOST_FORCEINLINE unsigned find_lsb(uint128_type mask, mpl::int_<0> const&)
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{
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union
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{
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uint128_type v;
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boost::uint64_t sv[2];
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} val;
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val.v = mask;
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#if BOOST_ENDIAN_LITTLE_BYTE
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if (val.sv[0] == 0)
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return find_lsb(val.sv[1], mpl::int_<3>()) + 64;
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return find_lsb(val.sv[0], mpl::int_<3>());
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#else
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if (val.sv[1] == 0)
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return find_lsb(val.sv[0], mpl::int_<3>()) + 64;
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return find_lsb(val.sv[1], mpl::int_<3>());
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#endif
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}
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#endif
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template <class Unsigned>
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BOOST_FORCEINLINE BOOST_MP_CXX14_CONSTEXPR unsigned find_lsb(Unsigned mask)
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{
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typedef typename make_unsigned<Unsigned>::type ui_type;
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typedef typename mpl::if_c<
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sizeof(Unsigned) <= sizeof(unsigned),
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mpl::int_<1>,
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typename mpl::if_c<
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sizeof(Unsigned) <= sizeof(unsigned long),
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mpl::int_<2>,
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typename mpl::if_c<
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sizeof(Unsigned) <= sizeof(boost::ulong_long_type),
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mpl::int_<3>,
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mpl::int_<0> >::type>::type>::type tag_type;
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#ifndef BOOST_MP_NO_CONSTEXPR_DETECTION
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if (BOOST_MP_IS_CONST_EVALUATED(mask))
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{
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return find_lsb_default(mask);
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}
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else
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#endif
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return find_lsb(static_cast<ui_type>(mask), tag_type());
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}
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template <class Unsigned>
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BOOST_FORCEINLINE BOOST_MP_CXX14_CONSTEXPR unsigned find_msb(Unsigned mask)
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{
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typedef typename make_unsigned<Unsigned>::type ui_type;
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typedef typename mpl::if_c<
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sizeof(Unsigned) <= sizeof(unsigned),
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mpl::int_<1>,
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typename mpl::if_c<
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sizeof(Unsigned) <= sizeof(unsigned long),
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mpl::int_<2>,
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typename mpl::if_c<
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sizeof(Unsigned) <= sizeof(boost::ulong_long_type),
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mpl::int_<3>,
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mpl::int_<0> >::type>::type>::type tag_type;
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#ifndef BOOST_MP_NO_CONSTEXPR_DETECTION
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if (BOOST_MP_IS_CONST_EVALUATED(mask))
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{
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return find_msb_default(mask);
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}
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else
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#endif
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return find_msb(static_cast<ui_type>(mask), tag_type());
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}
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#elif defined(BOOST_INTEL)
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BOOST_FORCEINLINE unsigned find_lsb(unsigned mask, mpl::int_<1> const&)
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{
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return _bit_scan_forward(mask);
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}
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BOOST_FORCEINLINE unsigned find_msb(unsigned mask, mpl::int_<1> const&)
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{
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return _bit_scan_reverse(mask);
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}
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template <class Unsigned>
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BOOST_FORCEINLINE BOOST_MP_CXX14_CONSTEXPR unsigned find_lsb(Unsigned mask)
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{
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typedef typename make_unsigned<Unsigned>::type ui_type;
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typedef typename mpl::if_c<
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sizeof(Unsigned) <= sizeof(unsigned),
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mpl::int_<1>,
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mpl::int_<0> >::type tag_type;
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#ifndef BOOST_MP_NO_CONSTEXPR_DETECTION
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if (BOOST_MP_IS_CONST_EVALUATED(mask))
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{
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return find_lsb_default(mask);
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}
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else
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#endif
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return find_lsb(static_cast<ui_type>(mask), tag_type());
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}
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template <class Unsigned>
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BOOST_FORCEINLINE BOOST_MP_CXX14_CONSTEXPR unsigned find_msb(Unsigned mask)
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{
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typedef typename make_unsigned<Unsigned>::type ui_type;
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typedef typename mpl::if_c<
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sizeof(Unsigned) <= sizeof(unsigned),
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mpl::int_<1>,
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mpl::int_<0> >::type tag_type;
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#ifndef BOOST_MP_NO_CONSTEXPR_DETECTION
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if (BOOST_MP_IS_CONST_EVALUATED(mask))
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{
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return find_msb_default(mask);
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}
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else
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#endif
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return find_msb(static_cast<ui_type>(mask), tag_type());
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}
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#else
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template <class Unsigned>
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BOOST_FORCEINLINE BOOST_MP_CXX14_CONSTEXPR unsigned find_lsb(Unsigned mask)
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{
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return find_lsb(mask, mpl::int_<0>());
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}
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template <class Unsigned>
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BOOST_FORCEINLINE BOOST_MP_CXX14_CONSTEXPR unsigned find_msb(Unsigned mask)
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{
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return find_msb(mask, mpl::int_<0>());
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}
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#endif
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}}} // namespace boost::multiprecision::detail
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#endif
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