| /* Boost interval/detail/alpha_rounding_control.hpp file |
| * |
| * Copyright 2005 Felix Höfling, Guillaume Melquiond |
| * |
| * 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_0.txt) |
| */ |
| |
| #ifndef BOOST_NUMERIC_INTERVAL_DETAIL_ALPHA_ROUNDING_CONTROL_HPP |
| #define BOOST_NUMERIC_INTERVAL_DETAIL_ALPHA_ROUNDING_CONTROL_HPP |
| |
| #if !defined(alpha) && !defined(__alpha__) |
| #error This header only works on Alpha CPUs. |
| #endif |
| |
| #if defined(__GNUC__) || defined(__digital__) || defined(__DECCXX) |
| |
| #include <float.h> // write_rnd() and read_rnd() |
| |
| namespace boost { |
| namespace numeric { |
| namespace interval_lib { |
| |
| namespace detail { |
| #if defined(__GNUC__ ) |
| typedef union { |
| ::boost::long_long_type imode; |
| double dmode; |
| } rounding_mode_struct; |
| |
| // set bits 59-58 (DYN), |
| // clear all exception bits and disable overflow (51) and inexact exceptions (62) |
| static const rounding_mode_struct mode_upward = { 0x4C08000000000000LL }; |
| static const rounding_mode_struct mode_downward = { 0x4408000000000000LL }; |
| static const rounding_mode_struct mode_to_nearest = { 0x4808000000000000LL }; |
| static const rounding_mode_struct mode_toward_zero = { 0x4008000000000000LL }; |
| |
| struct alpha_rounding_control |
| { |
| typedef double rounding_mode; |
| |
| static void set_rounding_mode(const rounding_mode mode) |
| { __asm__ __volatile__ ("mt_fpcr %0" : : "f"(mode)); } |
| |
| static void get_rounding_mode(rounding_mode& mode) |
| { __asm__ __volatile__ ("mf_fpcr %0" : "=f"(mode)); } |
| |
| static void downward() { set_rounding_mode(mode_downward.dmode); } |
| static void upward() { set_rounding_mode(mode_upward.dmode); } |
| static void to_nearest() { set_rounding_mode(mode_to_nearest.dmode); } |
| static void toward_zero() { set_rounding_mode(mode_toward_zero.dmode); } |
| }; |
| #elif defined(__digital__) || defined(__DECCXX) |
| |
| #if defined(__DECCXX) && !(defined(__FLT_ROUNDS) && __FLT_ROUNDS == -1) |
| #error Dynamic rounding mode not enabled. See cxx man page for details. |
| #endif |
| |
| struct alpha_rounding_control |
| { |
| typedef unsigned int rounding_mode; |
| |
| static void set_rounding_mode(const rounding_mode& mode) { write_rnd(mode); } |
| static void get_rounding_mode(rounding_mode& mode) { mode = read_rnd(); } |
| |
| static void downward() { set_rounding_mode(FP_RND_RM); } |
| static void upward() { set_rounding_mode(FP_RND_RP); } |
| static void to_nearest() { set_rounding_mode(FP_RND_RN); } |
| static void toward_zero() { set_rounding_mode(FP_RND_RZ); } |
| }; |
| #endif |
| } // namespace detail |
| |
| extern "C" { |
| float rintf(float); |
| double rint(double); |
| long double rintl(long double); |
| } |
| |
| template<> |
| struct rounding_control<float>: |
| detail::alpha_rounding_control |
| { |
| static float force_rounding(const float r) |
| { volatile float _r = r; return _r; } |
| static float to_int(const float& x) { return rintf(x); } |
| }; |
| |
| template<> |
| struct rounding_control<double>: |
| detail::alpha_rounding_control |
| { |
| static const double & force_rounding(const double& r) { return r; } |
| static double to_int(const double& r) { return rint(r); } |
| }; |
| |
| template<> |
| struct rounding_control<long double>: |
| detail::alpha_rounding_control |
| { |
| static const long double & force_rounding(const long double& r) { return r; } |
| static long double to_int(const long double& r) { return rintl(r); } |
| }; |
| |
| } // namespace interval_lib |
| } // namespace numeric |
| } // namespace boost |
| |
| #undef BOOST_NUMERIC_INTERVAL_NO_HARDWARE |
| #endif |
| |
| #endif /* BOOST_NUMERIC_INTERVAL_DETAIL_ALPHA_ROUNDING_CONTROL_HPP */ |