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- /* 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 */
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