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113 lines
3.5 KiB
113 lines
3.5 KiB
/* Boost interval/detail/alpha_rounding_control.hpp file |
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* |
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* Copyright 2005 Felix Höfling, Guillaume Melquiond |
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* |
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* Distributed under the Boost Software License, Version 1.0. |
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* (See accompanying file LICENSE_1_0.txt or |
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* copy at http://www.boost.org/LICENSE_1_0.txt) |
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*/ |
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#ifndef BOOST_NUMERIC_INTERVAL_DETAIL_ALPHA_ROUNDING_CONTROL_HPP |
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#define BOOST_NUMERIC_INTERVAL_DETAIL_ALPHA_ROUNDING_CONTROL_HPP |
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#if !defined(alpha) && !defined(__alpha__) |
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#error This header only works on Alpha CPUs. |
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#endif |
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#if defined(__GNUC__) || defined(__digital__) || defined(__DECCXX) |
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#include <float.h> // write_rnd() and read_rnd() |
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namespace boost { |
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namespace numeric { |
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namespace interval_lib { |
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namespace detail { |
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#if defined(__GNUC__ ) |
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typedef union { |
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::boost::long_long_type imode; |
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double dmode; |
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} rounding_mode_struct; |
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// set bits 59-58 (DYN), |
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// clear all exception bits and disable overflow (51) and inexact exceptions (62) |
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static const rounding_mode_struct mode_upward = { 0x4C08000000000000LL }; |
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static const rounding_mode_struct mode_downward = { 0x4408000000000000LL }; |
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static const rounding_mode_struct mode_to_nearest = { 0x4808000000000000LL }; |
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static const rounding_mode_struct mode_toward_zero = { 0x4008000000000000LL }; |
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struct alpha_rounding_control |
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{ |
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typedef double rounding_mode; |
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static void set_rounding_mode(const rounding_mode mode) |
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{ __asm__ __volatile__ ("mt_fpcr %0" : : "f"(mode)); } |
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static void get_rounding_mode(rounding_mode& mode) |
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{ __asm__ __volatile__ ("mf_fpcr %0" : "=f"(mode)); } |
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static void downward() { set_rounding_mode(mode_downward.dmode); } |
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static void upward() { set_rounding_mode(mode_upward.dmode); } |
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static void to_nearest() { set_rounding_mode(mode_to_nearest.dmode); } |
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static void toward_zero() { set_rounding_mode(mode_toward_zero.dmode); } |
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}; |
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#elif defined(__digital__) || defined(__DECCXX) |
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#if defined(__DECCXX) && !(defined(__FLT_ROUNDS) && __FLT_ROUNDS == -1) |
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#error Dynamic rounding mode not enabled. See cxx man page for details. |
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#endif |
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struct alpha_rounding_control |
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{ |
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typedef unsigned int rounding_mode; |
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static void set_rounding_mode(const rounding_mode& mode) { write_rnd(mode); } |
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static void get_rounding_mode(rounding_mode& mode) { mode = read_rnd(); } |
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static void downward() { set_rounding_mode(FP_RND_RM); } |
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static void upward() { set_rounding_mode(FP_RND_RP); } |
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static void to_nearest() { set_rounding_mode(FP_RND_RN); } |
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static void toward_zero() { set_rounding_mode(FP_RND_RZ); } |
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}; |
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#endif |
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} // namespace detail |
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extern "C" { |
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float rintf(float); |
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double rint(double); |
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long double rintl(long double); |
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} |
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template<> |
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struct rounding_control<float>: |
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detail::alpha_rounding_control |
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{ |
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static float force_rounding(const float r) |
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{ volatile float _r = r; return _r; } |
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static float to_int(const float& x) { return rintf(x); } |
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}; |
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template<> |
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struct rounding_control<double>: |
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detail::alpha_rounding_control |
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{ |
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static const double & force_rounding(const double& r) { return r; } |
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static double to_int(const double& r) { return rint(r); } |
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}; |
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template<> |
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struct rounding_control<long double>: |
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detail::alpha_rounding_control |
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{ |
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static const long double & force_rounding(const long double& r) { return r; } |
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static long double to_int(const long double& r) { return rintl(r); } |
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}; |
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} // namespace interval_lib |
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} // namespace numeric |
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} // namespace boost |
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#undef BOOST_NUMERIC_INTERVAL_NO_HARDWARE |
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#endif |
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#endif /* BOOST_NUMERIC_INTERVAL_DETAIL_ALPHA_ROUNDING_CONTROL_HPP */
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