1 ///////////////////////////////////////////////////////////////
2 // Copyright 2013 John Maddock. Distributed under the Boost
3 // Software License, Version 1.0. (See accompanying file
4 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_
6 // Comparison operators for cpp_int_backend:
8 #ifndef BOOST_MP_DETAIL_BITSCAN_HPP
9 #define BOOST_MP_DETAIL_BITSCAN_HPP
11 #include <boost/detail/endian.hpp>
13 #if (defined(BOOST_MSVC) || (defined(__clang__) && defined(__c2__)) || (defined(BOOST_INTEL) && defined(_MSC_VER))) && (defined(_M_IX86) || defined(_M_X64))
17 namespace boost{ namespace multiprecision{ namespace detail{
19 template <class Unsigned>
20 inline unsigned find_lsb(Unsigned mask, const mpl::int_<0>&)
31 template <class Unsigned>
32 inline unsigned find_msb(Unsigned mask, const mpl::int_<0>&)
43 #if (defined(BOOST_MSVC) || (defined(__clang__) && defined(__c2__)) || (defined(BOOST_INTEL) && defined(_MSC_VER))) && (defined(_M_IX86) || defined(_M_X64))
45 #pragma intrinsic(_BitScanForward,_BitScanReverse)
47 BOOST_FORCEINLINE unsigned find_lsb(unsigned long mask, const mpl::int_<1>&)
50 _BitScanForward(&result, mask);
54 BOOST_FORCEINLINE unsigned find_msb(unsigned long mask, const mpl::int_<1>&)
57 _BitScanReverse(&result, mask);
62 #pragma intrinsic(_BitScanForward64,_BitScanReverse64)
64 BOOST_FORCEINLINE unsigned find_lsb(unsigned __int64 mask, const mpl::int_<2>&)
67 _BitScanForward64(&result, mask);
70 template <class Unsigned>
71 BOOST_FORCEINLINE unsigned find_msb(Unsigned mask, const mpl::int_<2>&)
74 _BitScanReverse64(&result, mask);
79 template <class Unsigned>
80 BOOST_FORCEINLINE unsigned find_lsb(Unsigned mask)
82 typedef typename make_unsigned<Unsigned>::type ui_type;
83 typedef typename mpl::if_c<
84 sizeof(Unsigned) <= sizeof(unsigned long),
88 sizeof(Unsigned) <= sizeof(__int64),
96 return find_lsb(static_cast<ui_type>(mask), tag_type());
99 template <class Unsigned>
100 BOOST_FORCEINLINE unsigned find_msb(Unsigned mask)
102 typedef typename make_unsigned<Unsigned>::type ui_type;
103 typedef typename mpl::if_c<
104 sizeof(Unsigned) <= sizeof(unsigned long),
108 sizeof(Unsigned) <= sizeof(__int64),
116 return find_msb(static_cast<ui_type>(mask), tag_type());
119 #elif defined(BOOST_GCC) || defined(__clang__) || (defined(BOOST_INTEL) && defined(__GNUC__))
121 BOOST_FORCEINLINE unsigned find_lsb(unsigned mask, mpl::int_<1> const&)
123 return __builtin_ctz(mask);
125 BOOST_FORCEINLINE unsigned find_lsb(unsigned long mask, mpl::int_<2> const&)
127 return __builtin_ctzl(mask);
129 BOOST_FORCEINLINE unsigned find_lsb(boost::ulong_long_type mask, mpl::int_<3> const&)
131 return __builtin_ctzll(mask);
133 BOOST_FORCEINLINE unsigned find_msb(unsigned mask, mpl::int_<1> const&)
135 return sizeof(unsigned) * CHAR_BIT - 1 - __builtin_clz(mask);
137 BOOST_FORCEINLINE unsigned find_msb(unsigned long mask, mpl::int_<2> const&)
139 return sizeof(unsigned long) * CHAR_BIT - 1 - __builtin_clzl(mask);
141 BOOST_FORCEINLINE unsigned find_msb(boost::ulong_long_type mask, mpl::int_<3> const&)
143 return sizeof(boost::ulong_long_type) * CHAR_BIT - 1 - __builtin_clzll(mask);
145 #ifdef BOOST_HAS_INT128
146 BOOST_FORCEINLINE unsigned find_msb(unsigned __int128 mask, mpl::int_<0> const&)
148 union { unsigned __int128 v; boost::uint64_t sv[2]; } val;
150 #ifdef BOOST_LITTLE_ENDIAN
152 return find_msb(val.sv[1], mpl::int_<3>()) + 64;
153 return find_msb(val.sv[0], mpl::int_<3>());
156 return find_msb(val.sv[0], mpl::int_<3>()) + 64;
157 return find_msb(val.sv[1], mpl::int_<3>());
160 BOOST_FORCEINLINE unsigned find_lsb(unsigned __int128 mask, mpl::int_<0> const&)
162 union { unsigned __int128 v; boost::uint64_t sv[2]; } val;
164 #ifdef BOOST_LITTLE_ENDIAN
166 return find_lsb(val.sv[1], mpl::int_<3>()) + 64;
167 return find_lsb(val.sv[0], mpl::int_<3>());
170 return find_lsb(val.sv[0], mpl::int_<3>()) + 64;
171 return find_lsb(val.sv[1], mpl::int_<3>());
176 template <class Unsigned>
177 BOOST_FORCEINLINE unsigned find_lsb(Unsigned mask)
179 typedef typename make_unsigned<Unsigned>::type ui_type;
180 typedef typename mpl::if_c<
181 sizeof(Unsigned) <= sizeof(unsigned),
184 sizeof(Unsigned) <= sizeof(unsigned long),
187 sizeof(Unsigned) <= sizeof(boost::ulong_long_type),
193 return find_lsb(static_cast<ui_type>(mask), tag_type());
195 template <class Unsigned>
196 BOOST_FORCEINLINE unsigned find_msb(Unsigned mask)
198 typedef typename make_unsigned<Unsigned>::type ui_type;
199 typedef typename mpl::if_c<
200 sizeof(Unsigned) <= sizeof(unsigned),
203 sizeof(Unsigned) <= sizeof(unsigned long),
206 sizeof(Unsigned) <= sizeof(boost::ulong_long_type),
212 return find_msb(static_cast<ui_type>(mask), tag_type());
214 #elif defined(BOOST_INTEL)
215 BOOST_FORCEINLINE unsigned find_lsb(unsigned mask, mpl::int_<1> const&)
217 return _bit_scan_forward(mask);
219 BOOST_FORCEINLINE unsigned find_msb(unsigned mask, mpl::int_<1> const&)
221 return _bit_scan_reverse(mask);
223 template <class Unsigned>
224 BOOST_FORCEINLINE unsigned find_lsb(Unsigned mask)
226 typedef typename make_unsigned<Unsigned>::type ui_type;
227 typedef typename mpl::if_c<
228 sizeof(Unsigned) <= sizeof(unsigned),
232 return find_lsb(static_cast<ui_type>(mask), tag_type());
234 template <class Unsigned>
235 BOOST_FORCEINLINE unsigned find_msb(Unsigned mask)
237 typedef typename make_unsigned<Unsigned>::type ui_type;
238 typedef typename mpl::if_c<
239 sizeof(Unsigned) <= sizeof(unsigned),
243 return find_msb(static_cast<ui_type>(mask), tag_type());
246 template <class Unsigned>
247 BOOST_FORCEINLINE unsigned find_lsb(Unsigned mask)
249 return find_lsb(mask, mpl::int_<0>());
251 template <class Unsigned>
252 BOOST_FORCEINLINE unsigned find_msb(Unsigned mask)
254 return find_msb(mask, mpl::int_<0>());