Chris@16: /* Boost interval/detail/msvc_rounding_control.hpp file
Chris@16:  *
Chris@16:  * Copyright 2000 Maarten Keijzer
Chris@16:  * Copyright 2002 Hervé Brönnimann, Guillaume Melquiond, Sylvain Pion
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_MSVC_ROUNDING_CONTROL_HPP
Chris@16: #define BOOST_NUMERIC_INTERVAL_DETAIL_MSVC_ROUNDING_CONTROL_HPP
Chris@16: 
Chris@16: #ifndef _MSC_VER
Chris@16: #  error This header is only intended for MSVC, but might work for Borland as well
Chris@16: #endif
Chris@16: 
Chris@16: #include <float.h>      // MSVC rounding control
Chris@16: 
Chris@16: // Although the function is called _control87, it seems to work for
Chris@16: // other FPUs too, so it does not have to be changed to _controlfp.
Chris@16: 
Chris@16: namespace boost {
Chris@16: namespace numeric {
Chris@16: namespace interval_lib {
Chris@16: namespace detail {
Chris@16: 
Chris@16: #if BOOST_MSVC < 1400 || defined(_WIN64)
Chris@16: extern "C" { double rint(double); }
Chris@16: #else
Chris@16: inline double rint(double x)
Chris@16: {
Chris@16: _asm FLD [x] ;
Chris@16: _asm FRNDINT ;
Chris@16: //_asm RET ;
Chris@16: }
Chris@16: #endif
Chris@16: 
Chris@16: struct x86_rounding
Chris@16: {
Chris@16:   static unsigned int hard2msvc(unsigned short m) {
Chris@16:     unsigned int n = 0;
Chris@16:     if (m & 0x01) n |= _EM_INVALID;
Chris@16:     if (m & 0x02) n |= _EM_DENORMAL;
Chris@16:     if (m & 0x04) n |= _EM_ZERODIVIDE;
Chris@16:     if (m & 0x08) n |= _EM_OVERFLOW;
Chris@16:     if (m & 0x10) n |= _EM_UNDERFLOW;
Chris@16:     if (m & 0x20) n |= _EM_INEXACT;
Chris@16:     switch (m & 0x300) {
Chris@16:     case 0x000: n |= _PC_24; break;
Chris@16:     case 0x200: n |= _PC_53; break;
Chris@16:     case 0x300: n |= _PC_64; break;
Chris@16:     }
Chris@16:     switch (m & 0xC00) {
Chris@16:     case 0x000: n |= _RC_NEAR; break;
Chris@16:     case 0x400: n |= _RC_DOWN; break;
Chris@16:     case 0x800: n |= _RC_UP;   break;
Chris@16:     case 0xC00: n |= _RC_CHOP; break;
Chris@16:     }
Chris@16:     if (m & 0x1000) n |= _IC_AFFINE; // only useful on 287
Chris@16:     return n;
Chris@16:   }
Chris@16: 
Chris@16:   static unsigned short msvc2hard(unsigned int n) {
Chris@16:     unsigned short m = 0;
Chris@16:     if (n & _EM_INVALID)    m |= 0x01;
Chris@16:     if (n & _EM_DENORMAL)   m |= 0x02;
Chris@16:     if (n & _EM_ZERODIVIDE) m |= 0x04;
Chris@16:     if (n & _EM_OVERFLOW)   m |= 0x08;
Chris@16:     if (n & _EM_UNDERFLOW)  m |= 0x10;
Chris@16:     if (n & _EM_INEXACT)    m |= 0x20;
Chris@16:     switch (n & _MCW_RC) {
Chris@16:     case _RC_NEAR: m |= 0x000; break;
Chris@16:     case _RC_DOWN: m |= 0x400; break;
Chris@16:     case _RC_UP:   m |= 0x800; break;
Chris@16:     case _RC_CHOP: m |= 0xC00; break;
Chris@16:     }
Chris@16:     switch (n & _MCW_PC) {
Chris@16:     case _PC_24: m |= 0x000; break;
Chris@16:     case _PC_53: m |= 0x200; break;
Chris@16:     case _PC_64: m |= 0x300; break;
Chris@16:     }
Chris@16:     if ((n & _MCW_IC) == _IC_AFFINE) m |= 0x1000;
Chris@16:     return m;
Chris@16:   }
Chris@16: 
Chris@16:   typedef unsigned short rounding_mode;
Chris@16:   static void get_rounding_mode(rounding_mode& mode)
Chris@16:   { mode = msvc2hard(_control87(0, 0)); }
Chris@16:   static void set_rounding_mode(const rounding_mode mode)
Chris@101:   {
Chris@101:     _control87(hard2msvc(mode),
Chris@101:       _MCW_EM | _MCW_RC
Chris@101: #if !defined(_M_AMD64) && !defined(_M_ARM)
Chris@101:       // x64 ignores _MCW_PC and _MCW_IC, and the Debug CRT library actually
Chris@101:       // asserts when these are passed to _control87.
Chris@101:       // MSDN says on '_control87' that changing precision (_MCW_PC) or
Chris@101:       // infinity (_MCW_IC) handling is not supported on the ARM and x64
Chris@101:       // architectures and that _control87 raises an assertion
Chris@101:       // and the invalid parameter handler is invoked.
Chris@101:       | _MCW_PC | _MCW_IC
Chris@101: #endif
Chris@101:     );
Chris@101:   }
Chris@16:   static double to_int(const double& x) { return rint(x); }
Chris@16: };
Chris@16: 
Chris@16: } // namespace detail
Chris@16: } // namespace interval_lib
Chris@16: } // namespace numeric
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #endif /* BOOST_NUMERIC_INTERVAL_DETAIL_MSVC_ROUNDING_CONTROL_HPP */