/* 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 */ |