1 | /* Boost interval/detail/alpha_rounding_control.hpp file |
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2 | * |
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3 | * Copyright 2005 Felix Höfling, Guillaume Melquiond |
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4 | * |
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5 | * Distributed under the Boost Software License, Version 1.0. |
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6 | * (See accompanying file LICENSE_1_0.txt or |
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7 | * copy at http://www.boost.org/LICENSE_1_0.txt) |
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8 | */ |
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9 | |
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10 | #ifndef BOOST_NUMERIC_INTERVAL_DETAIL_ALPHA_ROUNDING_CONTROL_HPP |
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11 | #define BOOST_NUMERIC_INTERVAL_DETAIL_ALPHA_ROUNDING_CONTROL_HPP |
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12 | |
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13 | #if !defined(alpha) && !defined(__alpha__) |
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14 | #error This header only works on Alpha CPUs. |
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15 | #endif |
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16 | |
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17 | #if defined(__GNUC__) || defined(__digital__) || defined(__DECCXX) |
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18 | |
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19 | #include <float.h> // write_rnd() and read_rnd() |
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20 | |
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21 | namespace boost { |
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22 | namespace numeric { |
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23 | namespace interval_lib { |
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24 | |
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25 | namespace detail { |
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26 | #if defined(__GNUC__ ) |
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27 | typedef union { |
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28 | ::boost::long_long_type imode; |
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29 | double dmode; |
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30 | } rounding_mode_struct; |
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31 | |
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32 | // set bits 59-58 (DYN), |
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33 | // clear all exception bits and disable overflow (51) and inexact exceptions (62) |
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34 | static const rounding_mode_struct mode_upward = { 0x4C08000000000000LL }; |
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35 | static const rounding_mode_struct mode_downward = { 0x4408000000000000LL }; |
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36 | static const rounding_mode_struct mode_to_nearest = { 0x4808000000000000LL }; |
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37 | static const rounding_mode_struct mode_toward_zero = { 0x4008000000000000LL }; |
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38 | |
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39 | struct alpha_rounding_control |
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40 | { |
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41 | typedef double rounding_mode; |
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42 | |
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43 | static void set_rounding_mode(const rounding_mode mode) |
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44 | { __asm__ __volatile__ ("mt_fpcr %0" : : "f"(mode)); } |
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45 | |
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46 | static void get_rounding_mode(rounding_mode& mode) |
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47 | { __asm__ __volatile__ ("mf_fpcr %0" : "=f"(mode)); } |
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48 | |
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49 | static void downward() { set_rounding_mode(mode_downward.dmode); } |
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50 | static void upward() { set_rounding_mode(mode_upward.dmode); } |
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51 | static void to_nearest() { set_rounding_mode(mode_to_nearest.dmode); } |
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52 | static void toward_zero() { set_rounding_mode(mode_toward_zero.dmode); } |
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53 | }; |
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54 | #elif defined(__digital__) || defined(__DECCXX) |
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55 | |
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56 | #if defined(__DECCXX) && !(defined(__FLT_ROUNDS) && __FLT_ROUNDS == -1) |
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57 | #error Dynamic rounding mode not enabled. See cxx man page for details. |
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58 | #endif |
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59 | |
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60 | struct alpha_rounding_control |
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61 | { |
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62 | typedef unsigned int rounding_mode; |
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63 | |
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64 | static void set_rounding_mode(const rounding_mode& mode) { write_rnd(mode); } |
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65 | static void get_rounding_mode(rounding_mode& mode) { mode = read_rnd(); } |
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66 | |
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67 | static void downward() { set_rounding_mode(FP_RND_RM); } |
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68 | static void upward() { set_rounding_mode(FP_RND_RP); } |
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69 | static void to_nearest() { set_rounding_mode(FP_RND_RN); } |
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70 | static void toward_zero() { set_rounding_mode(FP_RND_RZ); } |
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71 | }; |
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72 | #endif |
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73 | } // namespace detail |
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74 | |
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75 | extern "C" { |
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76 | float rintf(float); |
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77 | double rint(double); |
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78 | long double rintl(long double); |
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79 | } |
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80 | |
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81 | template<> |
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82 | struct rounding_control<float>: |
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83 | detail::alpha_rounding_control |
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84 | { |
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85 | static float force_rounding(const float r) |
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86 | { volatile float _r = r; return _r; } |
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87 | static float to_int(const float& x) { return rintf(x); } |
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88 | }; |
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89 | |
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90 | template<> |
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91 | struct rounding_control<double>: |
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92 | detail::alpha_rounding_control |
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93 | { |
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94 | static const double & force_rounding(const double& r) { return r; } |
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95 | static double to_int(const double& r) { return rint(r); } |
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96 | }; |
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97 | |
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98 | template<> |
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99 | struct rounding_control<long double>: |
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100 | detail::alpha_rounding_control |
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101 | { |
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102 | static const long double & force_rounding(const long double& r) { return r; } |
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103 | static long double to_int(const long double& r) { return rintl(r); } |
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104 | }; |
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105 | |
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106 | } // namespace interval_lib |
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107 | } // namespace numeric |
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108 | } // namespace boost |
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109 | |
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110 | #undef BOOST_NUMERIC_INTERVAL_NO_HARDWARE |
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111 | #endif |
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112 | |
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113 | #endif /* BOOST_NUMERIC_INTERVAL_DETAIL_ALPHA_ROUNDING_CONTROL_HPP */ |
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