114 lines
3.4 KiB
Plaintext
114 lines
3.4 KiB
Plaintext
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/* 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 Herv<72> Br<42>nnimann, 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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{
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_control87(hard2msvc(mode),
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_MCW_EM | _MCW_RC
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#if !defined(_M_AMD64) && !defined(_M_ARM)
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// x64 ignores _MCW_PC and _MCW_IC, and the Debug CRT library actually
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// asserts when these are passed to _control87.
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// MSDN says on '_control87' that changing precision (_MCW_PC) or
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// infinity (_MCW_IC) handling is not supported on the ARM and x64
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// architectures and that _control87 raises an assertion
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// and the invalid parameter handler is invoked.
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| _MCW_PC | _MCW_IC
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#endif
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);
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}
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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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