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100 lines
2.9 KiB
100 lines
2.9 KiB
/* Boost interval/detail/msvc_rounding_control.hpp file |
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* |
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* Copyright 2000 Maarten Keijzer |
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* Copyright 2002 Hervé Brönnimann, Guillaume Melquiond, Sylvain Pion |
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* |
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* Distributed under the Boost Software License, Version 1.0. |
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* (See accompanying file LICENSE_1_0.txt or |
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* copy at http://www.boost.org/LICENSE_1_0.txt) |
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*/ |
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#ifndef BOOST_NUMERIC_INTERVAL_DETAIL_MSVC_ROUNDING_CONTROL_HPP |
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#define BOOST_NUMERIC_INTERVAL_DETAIL_MSVC_ROUNDING_CONTROL_HPP |
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#ifndef _MSC_VER |
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# error This header is only intended for MSVC, but might work for Borland as well |
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#endif |
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#include <float.h> // MSVC rounding control |
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// Although the function is called _control87, it seems to work for |
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// other FPUs too, so it does not have to be changed to _controlfp. |
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namespace boost { |
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namespace numeric { |
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namespace interval_lib { |
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namespace detail { |
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#if BOOST_MSVC < 1400 || defined(WIN64) |
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extern "C" { double rint(double); } |
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#else |
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inline double rint(double x) |
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{ |
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_asm FLD [x] ; |
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_asm FRNDINT ; |
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//_asm RET ; |
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} |
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#endif |
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struct x86_rounding |
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{ |
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static unsigned int hard2msvc(unsigned short m) { |
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unsigned int n = 0; |
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if (m & 0x01) n |= _EM_INVALID; |
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if (m & 0x02) n |= _EM_DENORMAL; |
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if (m & 0x04) n |= _EM_ZERODIVIDE; |
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if (m & 0x08) n |= _EM_OVERFLOW; |
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if (m & 0x10) n |= _EM_UNDERFLOW; |
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if (m & 0x20) n |= _EM_INEXACT; |
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switch (m & 0x300) { |
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case 0x000: n |= _PC_24; break; |
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case 0x200: n |= _PC_53; break; |
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case 0x300: n |= _PC_64; break; |
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} |
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switch (m & 0xC00) { |
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case 0x000: n |= _RC_NEAR; break; |
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case 0x400: n |= _RC_DOWN; break; |
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case 0x800: n |= _RC_UP; break; |
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case 0xC00: n |= _RC_CHOP; break; |
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} |
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if (m & 0x1000) n |= _IC_AFFINE; // only useful on 287 |
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return n; |
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} |
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static unsigned short msvc2hard(unsigned int n) { |
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unsigned short m = 0; |
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if (n & _EM_INVALID) m |= 0x01; |
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if (n & _EM_DENORMAL) m |= 0x02; |
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if (n & _EM_ZERODIVIDE) m |= 0x04; |
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if (n & _EM_OVERFLOW) m |= 0x08; |
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if (n & _EM_UNDERFLOW) m |= 0x10; |
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if (n & _EM_INEXACT) m |= 0x20; |
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switch (n & _MCW_RC) { |
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case _RC_NEAR: m |= 0x000; break; |
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case _RC_DOWN: m |= 0x400; break; |
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case _RC_UP: m |= 0x800; break; |
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case _RC_CHOP: m |= 0xC00; break; |
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} |
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switch (n & _MCW_PC) { |
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case _PC_24: m |= 0x000; break; |
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case _PC_53: m |= 0x200; break; |
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case _PC_64: m |= 0x300; break; |
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} |
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if ((n & _MCW_IC) == _IC_AFFINE) m |= 0x1000; |
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return m; |
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} |
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typedef unsigned short rounding_mode; |
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static void get_rounding_mode(rounding_mode& mode) |
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{ mode = msvc2hard(_control87(0, 0)); } |
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static void set_rounding_mode(const rounding_mode mode) |
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{ _control87(hard2msvc(mode), _MCW_EM | _MCW_RC | _MCW_PC | _MCW_IC); } |
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static double to_int(const double& x) { return rint(x); } |
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}; |
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} // namespace detail |
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} // namespace interval_lib |
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} // namespace numeric |
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} // namespace boost |
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#endif /* BOOST_NUMERIC_INTERVAL_DETAIL_MSVC_ROUNDING_CONTROL_HPP */
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