Chris@16: /* Boost interval/detail/alpha_rounding_control.hpp file
Chris@16:  *
Chris@16:  * Copyright 2005 Felix Höfling, Guillaume Melquiond
Chris@16:  *
Chris@16:  * Distributed under the Boost Software License, Version 1.0.
Chris@16:  * (See accompanying file LICENSE_1_0.txt or
Chris@16:  * copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16:  */
Chris@16: 
Chris@16: #ifndef BOOST_NUMERIC_INTERVAL_DETAIL_ALPHA_ROUNDING_CONTROL_HPP
Chris@16: #define BOOST_NUMERIC_INTERVAL_DETAIL_ALPHA_ROUNDING_CONTROL_HPP
Chris@16: 
Chris@16: #if !defined(alpha) && !defined(__alpha__)
Chris@16: #error This header only works on Alpha CPUs.
Chris@16: #endif
Chris@16: 
Chris@16: #if defined(__GNUC__) || defined(__digital__) || defined(__DECCXX)
Chris@16: 
Chris@16: #include <float.h> // write_rnd() and read_rnd()
Chris@16: 
Chris@16: namespace boost {
Chris@16: namespace numeric {
Chris@16: namespace interval_lib {
Chris@16: 
Chris@16: namespace detail {
Chris@16: #if defined(__GNUC__ )
Chris@16:     typedef union {
Chris@16:     ::boost::long_long_type imode;
Chris@16:     double dmode;
Chris@16:     } rounding_mode_struct;
Chris@16: 
Chris@16:     // set bits 59-58 (DYN),
Chris@16:     // clear all exception bits and disable overflow (51) and inexact exceptions (62)
Chris@16:     static const rounding_mode_struct mode_upward      = { 0x4C08000000000000LL };
Chris@16:     static const rounding_mode_struct mode_downward    = { 0x4408000000000000LL };
Chris@16:     static const rounding_mode_struct mode_to_nearest  = { 0x4808000000000000LL };
Chris@16:     static const rounding_mode_struct mode_toward_zero = { 0x4008000000000000LL };
Chris@16: 
Chris@16:     struct alpha_rounding_control
Chris@16:     {
Chris@16:     typedef double rounding_mode;
Chris@16: 
Chris@16:     static void set_rounding_mode(const rounding_mode mode)
Chris@16:     { __asm__ __volatile__ ("mt_fpcr %0" : : "f"(mode)); }
Chris@16: 
Chris@16:     static void get_rounding_mode(rounding_mode& mode)
Chris@16:     { __asm__ __volatile__ ("mf_fpcr %0" : "=f"(mode)); }
Chris@16: 
Chris@16:     static void downward()    { set_rounding_mode(mode_downward.dmode);    }
Chris@16:     static void upward()      { set_rounding_mode(mode_upward.dmode);      }
Chris@16:     static void to_nearest()  { set_rounding_mode(mode_to_nearest.dmode);  }
Chris@16:     static void toward_zero() { set_rounding_mode(mode_toward_zero.dmode); }
Chris@16:     };
Chris@16: #elif defined(__digital__) || defined(__DECCXX)
Chris@16: 
Chris@16: #if defined(__DECCXX) && !(defined(__FLT_ROUNDS) && __FLT_ROUNDS == -1)
Chris@16: #error Dynamic rounding mode not enabled. See cxx man page for details.
Chris@16: #endif
Chris@16: 
Chris@16:     struct alpha_rounding_control
Chris@16:     {
Chris@16:     typedef unsigned int rounding_mode;
Chris@16: 
Chris@16:     static void set_rounding_mode(const rounding_mode& mode)  { write_rnd(mode); }
Chris@16:     static void get_rounding_mode(rounding_mode& mode)  { mode = read_rnd(); }
Chris@16: 
Chris@16:     static void downward()    { set_rounding_mode(FP_RND_RM); }
Chris@16:     static void upward()      { set_rounding_mode(FP_RND_RP); }
Chris@16:     static void to_nearest()  { set_rounding_mode(FP_RND_RN); }
Chris@16:     static void toward_zero() { set_rounding_mode(FP_RND_RZ); }
Chris@16:     };
Chris@16: #endif
Chris@16: } // namespace detail
Chris@16: 
Chris@16: extern "C" {
Chris@16:   float rintf(float);
Chris@16:   double rint(double);
Chris@16:   long double rintl(long double);
Chris@16: }
Chris@16: 
Chris@16: template<>
Chris@16: struct rounding_control<float>:
Chris@16:   detail::alpha_rounding_control
Chris@16: {
Chris@16:   static float force_rounding(const float r)
Chris@16:   { volatile float _r = r; return _r; }
Chris@16:   static float to_int(const float& x) { return rintf(x); }
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct rounding_control<double>:
Chris@16:   detail::alpha_rounding_control
Chris@16: {
Chris@16:   static const double & force_rounding(const double& r) { return r; }
Chris@16:   static double to_int(const double& r) { return rint(r); }
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct rounding_control<long double>:
Chris@16:   detail::alpha_rounding_control
Chris@16: {
Chris@16:   static const long double & force_rounding(const long double& r) { return r; }
Chris@16:   static long double to_int(const long double& r) { return rintl(r); }
Chris@16: };
Chris@16: 
Chris@16: } // namespace interval_lib
Chris@16: } // namespace numeric
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #undef BOOST_NUMERIC_INTERVAL_NO_HARDWARE
Chris@16: #endif
Chris@16: 
Chris@16: #endif /* BOOST_NUMERIC_INTERVAL_DETAIL_ALPHA_ROUNDING_CONTROL_HPP */