boost/numeric/interval/detail/ppc_rounding_control.hpp
/* Boost interval/detail/ppc_rounding_control.hpp file
*
* Copyright Jens Maurer 2000
* Copyright Herv� Br�nnimann, Guillaume Melquiond, Sylvain Pion 2002
* Permission to use, copy, modify, sell, and distribute this software
* is hereby granted without fee provided that the above copyright notice
* appears in all copies and that both that copyright notice and this
* permission notice appear in supporting documentation,
*
* None of the above authors nor Polytechnic University make any
* representation about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*
* $Id: ppc_rounding_control.hpp,v 1.2 2003/02/05 17:34:32 gmelquio Exp $
*/
#ifndef BOOST_NUMERIC_INTERVAL_DETAIL_PPC_ROUNDING_CONTROL_HPP
#define BOOST_NUMERIC_INTERVAL_DETAIL_PPC_ROUNDING_CONTROL_HPP
#ifndef __GNUC__
#error This header only works with GNU CC.
#endif
#if !defined(powerpc) && !defined(__powerpc__) && !defined(__ppc__)
#error This header only works on PPC CPUs.
#endif
namespace boost {
namespace numeric {
namespace interval_lib {
namespace detail {
typedef union {
long long int imode;
double dmode;
} rounding_mode_struct;
static const rounding_mode_struct mode_upward = { 0xFFF8000000000002LL };
static const rounding_mode_struct mode_downward = { 0xFFF8000000000003LL };
static const rounding_mode_struct mode_to_nearest = { 0xFFF8000000000001LL };
static const rounding_mode_struct mode_toward_zero = { 0xFFF8000000000000LL };
struct ppc_rounding_control
{
typedef double rounding_mode;
static void set_rounding_mode(const rounding_mode mode)
{ __asm__ __volatile__ ("mtfsf 255,%0" : : "f"(mode)); }
static void get_rounding_mode(rounding_mode& mode)
{ __asm__ __volatile__ ("mffs %0" : "=f"(mode)); }
static void downward() { set_rounding_mode(mode_downward.dmode); }
static void upward() { set_rounding_mode(mode_upward.dmode); }
static void to_nearest() { set_rounding_mode(mode_to_nearest.dmode); }
static void toward_zero() { set_rounding_mode(mode_toward_zero.dmode); }
};
} // namespace detail
extern "C" {
float rintf(float);
double rint(double);
}
template<>
struct rounding_control<float>:
detail::ppc_rounding_control
{
static float force_rounding(const float r)
{
float tmp;
__asm__ __volatile__ ("frsp %0, %1" : "=f" (tmp) : "f" (r));
return tmp;
}
static float to_int(const float& x) { return rintf(x); }
};
template<>
struct rounding_control<double>:
detail::ppc_rounding_control
{
static const double & force_rounding(const double& r) { return r; }
static double to_int(const double& r) { return rint(r); }
};
template<>
struct rounding_control<long double>:
detail::ppc_rounding_control
{
static const long double & force_rounding(const long double& r) { return r; }
static long double to_int(const long double& r) { return rint(r); }
};
} // namespace interval_lib
} // namespace numeric
} // namespace boost
#endif /* BOOST_NUMERIC_INTERVAL_DETAIL_PPC_ROUNDING_CONTROL_HPP */