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