1 /* Boost interval/detail/x86gcc_rounding_control.hpp file 2 * 3 * This header provides a rounding control policy 4 * that avoids flushing results to memory. In 5 * order for this optimization to be reliable, it 6 * should be used only when no underflow or 7 * overflow would happen without it. Indeed, only 8 * values in range are correctly rounded. 9 * 10 * Copyright 2002 Herv� Br�nnimann, Guillaume Melquiond, Sylvain Pion 11 * 12 * Distributed under the Boost Software License, Version 1.0. 13 * (See accompanying file LICENSE_1_0.txt or 14 * copy at http://www.boost.org/LICENSE_1_0.txt) 15 */ 16 17 #ifndef BOOST_NUMERIC_INTERVAL_EXT_X86_FAST_ROUNDING_CONTROL_HPP 18 #define BOOST_NUMERIC_INTERVAL_EXT_X86_FAST_ROUNDING_CONTROL_HPP 19 20 namespace boost { 21 namespace numeric { 22 namespace interval_lib { 23 24 namespace detail { 25 26 // exceptions masked, expected precision (the mask is 0x0300) 27 static const fpu_rounding_modes rnd_mode_f = { 0x107f, 0x147f, 0x187f, 0x1c7f }; 28 static const fpu_rounding_modes rnd_mode_d = { 0x127f, 0x167f, 0x1a7f, 0x1e7f }; 29 static const fpu_rounding_modes rnd_mode_l = { 0x137f, 0x177f, 0x1b7f, 0x1f7f }; 30 31 } // namespace detail 32 33 template<class T> 34 struct x86_fast_rounding_control; 35 36 template<> 37 struct x86_fast_rounding_control<float>: detail::x86_rounding 38 { to_nearestboost::numeric::interval_lib::x86_fast_rounding_control39 static void to_nearest() { set_rounding_mode(detail::rnd_mode_f.to_nearest); } downwardboost::numeric::interval_lib::x86_fast_rounding_control40 static void downward() { set_rounding_mode(detail::rnd_mode_f.downward); } upwardboost::numeric::interval_lib::x86_fast_rounding_control41 static void upward() { set_rounding_mode(detail::rnd_mode_f.upward); } toward_zeroboost::numeric::interval_lib::x86_fast_rounding_control42 static void toward_zero() { set_rounding_mode(detail::rnd_mode_f.toward_zero); } force_roundingboost::numeric::interval_lib::x86_fast_rounding_control43 static const float& force_rounding(const float& r) { return r; } 44 }; 45 46 template<> 47 struct x86_fast_rounding_control<double>: detail::x86_rounding 48 { to_nearestboost::numeric::interval_lib::x86_fast_rounding_control49 static void to_nearest() { set_rounding_mode(detail::rnd_mode_d.to_nearest); } downwardboost::numeric::interval_lib::x86_fast_rounding_control50 static void downward() { set_rounding_mode(detail::rnd_mode_d.downward); } upwardboost::numeric::interval_lib::x86_fast_rounding_control51 static void upward() { set_rounding_mode(detail::rnd_mode_d.upward); } toward_zeroboost::numeric::interval_lib::x86_fast_rounding_control52 static void toward_zero() { set_rounding_mode(detail::rnd_mode_d.toward_zero); } force_roundingboost::numeric::interval_lib::x86_fast_rounding_control53 static const double& force_rounding(const double& r) { return r; } 54 }; 55 56 template<> 57 struct x86_fast_rounding_control<long double>: detail::x86_rounding 58 { to_nearestboost::numeric::interval_lib::x86_fast_rounding_control59 static void to_nearest() { set_rounding_mode(detail::rnd_mode_l.to_nearest); } downwardboost::numeric::interval_lib::x86_fast_rounding_control60 static void downward() { set_rounding_mode(detail::rnd_mode_l.downward); } upwardboost::numeric::interval_lib::x86_fast_rounding_control61 static void upward() { set_rounding_mode(detail::rnd_mode_l.upward); } toward_zeroboost::numeric::interval_lib::x86_fast_rounding_control62 static void toward_zero() { set_rounding_mode(detail::rnd_mode_l.toward_zero); } force_roundingboost::numeric::interval_lib::x86_fast_rounding_control63 static const long double& force_rounding(const long double& r) { return r; } 64 }; 65 66 } // namespace interval_lib 67 } // namespace numeric 68 } // namespace boost 69 70 #endif // BOOST_NUMERIC_INTERVAL_EXT_X86_FAST_ROUNDING_CONTROL_HPP 71