| 1 | /* Boost interval/detail/msvc_rounding_control.hpp file |
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| 2 | * |
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| 3 | * Copyright 2000 Maarten Keijzer |
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| 4 | * Copyright 2002 Hervé Brönnimann, Guillaume Melquiond, Sylvain Pion |
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| 5 | * |
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| 6 | * Distributed under the Boost Software License, Version 1.0. |
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| 7 | * (See accompanying file LICENSE_1_0.txt or |
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| 8 | * copy at http://www.boost.org/LICENSE_1_0.txt) |
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| 9 | */ |
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| 10 | |
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| 11 | #ifndef BOOST_NUMERIC_INTERVAL_DETAIL_MSVC_ROUNDING_CONTROL_HPP |
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| 12 | #define BOOST_NUMERIC_INTERVAL_DETAIL_MSVC_ROUNDING_CONTROL_HPP |
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| 13 | |
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| 14 | #ifndef _MSC_VER |
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| 15 | # error This header is only intended for MSVC, but might work for Borland as well |
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| 16 | #endif |
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| 17 | |
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| 18 | #include <float.h> // MSVC rounding control |
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| 19 | |
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| 20 | // Although the function is called _control87, it seems to work for |
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| 21 | // other FPUs too, so it does not have to be changed to _controlfp. |
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| 22 | |
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| 23 | namespace boost { |
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| 24 | namespace numeric { |
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| 25 | namespace interval_lib { |
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| 26 | namespace detail { |
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| 27 | |
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| 28 | extern "C" { double rint(double); } |
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| 29 | |
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| 30 | struct x86_rounding |
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| 31 | { |
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| 32 | static unsigned int hard2msvc(unsigned short m) { |
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| 33 | unsigned int n = 0; |
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| 34 | if (m & 0x01) n |= _EM_INVALID; |
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| 35 | if (m & 0x02) n |= _EM_DENORMAL; |
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| 36 | if (m & 0x04) n |= _EM_ZERODIVIDE; |
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| 37 | if (m & 0x08) n |= _EM_OVERFLOW; |
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| 38 | if (m & 0x10) n |= _EM_UNDERFLOW; |
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| 39 | if (m & 0x20) n |= _EM_INEXACT; |
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| 40 | switch (m & 0x300) { |
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| 41 | case 0x000: n |= _PC_24; break; |
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| 42 | case 0x200: n |= _PC_53; break; |
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| 43 | case 0x300: n |= _PC_64; break; |
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| 44 | } |
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| 45 | switch (m & 0xC00) { |
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| 46 | case 0x000: n |= _RC_NEAR; break; |
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| 47 | case 0x400: n |= _RC_DOWN; break; |
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| 48 | case 0x800: n |= _RC_UP; break; |
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| 49 | case 0xC00: n |= _RC_CHOP; break; |
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| 50 | } |
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| 51 | if (m & 0x1000) n |= _IC_AFFINE; // only useful on 287 |
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| 52 | return n; |
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| 53 | } |
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| 54 | |
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| 55 | static unsigned short msvc2hard(unsigned int n) { |
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| 56 | unsigned short m = 0; |
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| 57 | if (n & _EM_INVALID) m |= 0x01; |
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| 58 | if (n & _EM_DENORMAL) m |= 0x02; |
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| 59 | if (n & _EM_ZERODIVIDE) m |= 0x04; |
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| 60 | if (n & _EM_OVERFLOW) m |= 0x08; |
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| 61 | if (n & _EM_UNDERFLOW) m |= 0x10; |
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| 62 | if (n & _EM_INEXACT) m |= 0x20; |
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| 63 | switch (n & _MCW_RC) { |
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| 64 | case _RC_NEAR: m |= 0x000; break; |
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| 65 | case _RC_DOWN: m |= 0x400; break; |
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| 66 | case _RC_UP: m |= 0x800; break; |
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| 67 | case _RC_CHOP: m |= 0xC00; break; |
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| 68 | } |
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| 69 | switch (n & _MCW_PC) { |
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| 70 | case _PC_24: m |= 0x000; break; |
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| 71 | case _PC_53: m |= 0x200; break; |
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| 72 | case _PC_64: m |= 0x300; break; |
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| 73 | } |
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| 74 | if ((n & _MCW_IC) == _IC_AFFINE) m |= 0x1000; |
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| 75 | return m; |
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| 76 | } |
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| 77 | |
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| 78 | typedef unsigned short rounding_mode; |
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| 79 | static void get_rounding_mode(rounding_mode& mode) |
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| 80 | { mode = msvc2hard(_control87(0, 0)); } |
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| 81 | static void set_rounding_mode(const rounding_mode mode) |
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| 82 | { _control87(hard2msvc(mode), _MCW_EM | _MCW_RC | _MCW_PC | _MCW_IC); } |
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| 83 | static double to_int(const double& x) { return rint(x); } |
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| 84 | }; |
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| 85 | |
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| 86 | } // namespace detail |
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| 87 | } // namespace interval_lib |
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| 88 | } // namespace numeric |
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| 89 | } // namespace boost |
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| 90 | |
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| 91 | #endif /* BOOST_NUMERIC_INTERVAL_DETAIL_MSVC_ROUNDING_CONTROL_HPP */ |
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