/////////////////////////////////////////////////////////////// // Copyright 2013 John Maddock. Distributed under the Boost // Software License, Version 1.0. (See accompanying file // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_ // // Comparison operators for cpp_int_backend: // #ifndef BOOST_MP_DETAIL_BITSCAN_HPP #define BOOST_MP_DETAIL_BITSCAN_HPP #if (defined(BOOST_MSVC) || (defined(__clang__) && defined(__c2__)) || (defined(BOOST_INTEL) && defined(_MSC_VER))) && (defined(_M_IX86) || defined(_M_X64)) #include <intrin.h> #endif namespace boost{ namespace multiprecision{ namespace detail{ template <class Unsigned> inline unsigned find_lsb(Unsigned mask, const mpl::int_<0>&) { unsigned result = 0; while(!(mask & 1u)) { mask >>= 1; ++result; } return result; } template <class Unsigned> inline unsigned find_msb(Unsigned mask, const mpl::int_<0>&) { unsigned index = 0; while(mask) { ++index; mask >>= 1; } return --index; } #if (defined(BOOST_MSVC) || (defined(__clang__) && defined(__c2__)) || (defined(BOOST_INTEL) && defined(_MSC_VER))) && (defined(_M_IX86) || defined(_M_X64)) #pragma intrinsic(_BitScanForward,_BitScanReverse) BOOST_FORCEINLINE unsigned find_lsb(unsigned long mask, const mpl::int_<1>&) { unsigned long result; _BitScanForward(&result, mask); return result; } BOOST_FORCEINLINE unsigned find_msb(unsigned long mask, const mpl::int_<1>&) { unsigned long result; _BitScanReverse(&result, mask); return result; } #ifdef _M_X64 #pragma intrinsic(_BitScanForward64,_BitScanReverse64) BOOST_FORCEINLINE unsigned find_lsb(unsigned __int64 mask, const mpl::int_<2>&) { unsigned long result; _BitScanForward64(&result, mask); return result; } template <class Unsigned> BOOST_FORCEINLINE unsigned find_msb(Unsigned mask, const mpl::int_<2>&) { unsigned long result; _BitScanReverse64(&result, mask); return result; } #endif template <class Unsigned> BOOST_FORCEINLINE unsigned find_lsb(Unsigned mask) { typedef typename make_unsigned<Unsigned>::type ui_type; typedef typename mpl::if_c< sizeof(Unsigned) <= sizeof(unsigned long), mpl::int_<1>, #ifdef _M_X64 typename mpl::if_c< sizeof(Unsigned) <= sizeof(__int64), mpl::int_<2>, mpl::int_<0> >::type #else mpl::int_<0> #endif >::type tag_type; return find_lsb(static_cast<ui_type>(mask), tag_type()); } template <class Unsigned> BOOST_FORCEINLINE unsigned find_msb(Unsigned mask) { typedef typename make_unsigned<Unsigned>::type ui_type; typedef typename mpl::if_c< sizeof(Unsigned) <= sizeof(unsigned long), mpl::int_<1>, #ifdef _M_X64 typename mpl::if_c< sizeof(Unsigned) <= sizeof(__int64), mpl::int_<2>, mpl::int_<0> >::type #else mpl::int_<0> #endif >::type tag_type; return find_msb(static_cast<ui_type>(mask), tag_type()); } #elif defined(BOOST_GCC) || defined(__clang__) || (defined(BOOST_INTEL) && defined(__GNUC__)) BOOST_FORCEINLINE unsigned find_lsb(unsigned mask, mpl::int_<1> const&) { return __builtin_ctz(mask); } BOOST_FORCEINLINE unsigned find_lsb(unsigned long mask, mpl::int_<2> const&) { return __builtin_ctzl(mask); } BOOST_FORCEINLINE unsigned find_lsb(boost::ulong_long_type mask, mpl::int_<3> const&) { return __builtin_ctzll(mask); } BOOST_FORCEINLINE unsigned find_msb(unsigned mask, mpl::int_<1> const&) { return sizeof(unsigned) * CHAR_BIT - 1 - __builtin_clz(mask); } BOOST_FORCEINLINE unsigned find_msb(unsigned long mask, mpl::int_<2> const&) { return sizeof(unsigned long) * CHAR_BIT - 1 - __builtin_clzl(mask); } BOOST_FORCEINLINE unsigned find_msb(boost::ulong_long_type mask, mpl::int_<3> const&) { return sizeof(boost::ulong_long_type) * CHAR_BIT - 1 - __builtin_clzll(mask); } template <class Unsigned> BOOST_FORCEINLINE unsigned find_lsb(Unsigned mask) { typedef typename make_unsigned<Unsigned>::type ui_type; typedef typename mpl::if_c< sizeof(Unsigned) <= sizeof(unsigned), mpl::int_<1>, typename mpl::if_c< sizeof(Unsigned) <= sizeof(unsigned long), mpl::int_<2>, typename mpl::if_c< sizeof(Unsigned) <= sizeof(boost::ulong_long_type), mpl::int_<3>, mpl::int_<0> >::type >::type >::type tag_type; return find_lsb(static_cast<ui_type>(mask), tag_type()); } template <class Unsigned> BOOST_FORCEINLINE unsigned find_msb(Unsigned mask) { typedef typename make_unsigned<Unsigned>::type ui_type; typedef typename mpl::if_c< sizeof(Unsigned) <= sizeof(unsigned), mpl::int_<1>, typename mpl::if_c< sizeof(Unsigned) <= sizeof(unsigned long), mpl::int_<2>, typename mpl::if_c< sizeof(Unsigned) <= sizeof(boost::ulong_long_type), mpl::int_<3>, mpl::int_<0> >::type >::type >::type tag_type; return find_msb(static_cast<ui_type>(mask), tag_type()); } #elif defined(BOOST_INTEL) BOOST_FORCEINLINE unsigned find_lsb(unsigned mask, mpl::int_<1> const&) { return _bit_scan_forward(mask); } BOOST_FORCEINLINE unsigned find_msb(unsigned mask, mpl::int_<1> const&) { return _bit_scan_reverse(mask); } template <class Unsigned> BOOST_FORCEINLINE unsigned find_lsb(Unsigned mask) { typedef typename make_unsigned<Unsigned>::type ui_type; typedef typename mpl::if_c< sizeof(Unsigned) <= sizeof(unsigned), mpl::int_<1>, mpl::int_<0> >::type tag_type; return find_lsb(static_cast<ui_type>(mask), tag_type()); } template <class Unsigned> BOOST_FORCEINLINE unsigned find_msb(Unsigned mask) { typedef typename make_unsigned<Unsigned>::type ui_type; typedef typename mpl::if_c< sizeof(Unsigned) <= sizeof(unsigned), mpl::int_<1>, mpl::int_<0> >::type tag_type; return find_msb(static_cast<ui_type>(mask), tag_type()); } #else template <class Unsigned> BOOST_FORCEINLINE unsigned find_lsb(Unsigned mask) { return find_lsb(mask, mpl::int_<0>()); } template <class Unsigned> BOOST_FORCEINLINE unsigned find_msb(Unsigned mask) { return find_msb(mask, mpl::int_<0>()); } #endif }}} #endif