/* ieee-utils/fp-gnuc99.c

 * 

 * Copyright (C) 2003, 2004, 2007 Brian Gough

 * 

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 3 of the License, or (at

 * your option) any later version.

 * 

 * This program is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * General Public License for more details.

 * 

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

 */

#define _GNU_SOURCE 1

#include <math.h>

#include <stdio.h>

#include <fenv.h>

#include <gsl/gsl_ieee_utils.h>

#include <gsl/gsl_errno.h>

int

gsl_ieee_set_mode (int precision, int rounding, int exception_mask)

{

  int mode;

  switch (precision)

    {

    case GSL_IEEE_SINGLE_PRECISION:

      GSL_ERROR ("single precision rounding is not supported by <fenv.h>",

                 GSL_EUNSUP) ;

      break ;

    case GSL_IEEE_DOUBLE_PRECISION:

      GSL_ERROR ("double precision rounding is not supported by <fenv.h>",

                 GSL_EUNSUP) ;

      break ;

    case GSL_IEEE_EXTENDED_PRECISION:

      GSL_ERROR ("extended precision rounding is not supported by <fenv.h>",

                 GSL_EUNSUP) ;

      break ;

    }

  switch (rounding)

    {

    case GSL_IEEE_ROUND_TO_NEAREST:

#ifdef FE_TONEAREST

      fesetround (FE_TONEAREST) ;

#else

      GSL_ERROR ("round-to-nearest is not supported by <fenv.h>", GSL_EUNSUP) ;

#endif

      break ;

    case GSL_IEEE_ROUND_DOWN:

#ifdef FE_DOWNWARD

      fesetround (FE_DOWNWARD) ;

#else

      GSL_ERROR ("round-down is not supported by <fenv.h>", GSL_EUNSUP) ;

#endif

      break ;

    case GSL_IEEE_ROUND_UP:

#ifdef FE_UPWARD

      fesetround (FE_UPWARD) ;

#else

      GSL_ERROR ("round-up is not supported by <fenv.h>", GSL_EUNSUP) ;

#endif

      break ;

    case GSL_IEEE_ROUND_TO_ZERO:

#ifdef FE_TOWARDZERO

      fesetround (FE_TOWARDZERO) ;

#else

      GSL_ERROR ("round-toward-zero is not supported by <fenv.h>", GSL_EUNSUP) ;

#endif

      break ;

    default:

#ifdef FE_TONEAREST

      fesetround (FE_TONEAREST) ;

#else

      GSL_ERROR ("default round-to-nearest mode is not supported by <fenv.h>", GSL_EUNSUP) ;

#endif

    }

  /* Turn on all the exceptions apart from 'inexact' */

  mode = 0;

#ifdef FE_INVALID 

  mode |= FE_INVALID;

#endif

#ifdef FE_DIVBYZERO

  mode |= FE_DIVBYZERO;

#endif

#ifdef FE_OVERFLOW

  mode |= FE_OVERFLOW ;

#endif

#ifdef FE_UNDERFLOW

  mode |= FE_UNDERFLOW ;

#endif

  if (exception_mask & GSL_IEEE_MASK_INVALID)

    {

#ifdef FE_INVALID

    mode &= ~ FE_INVALID ;

#else

    GSL_ERROR ("invalid operation exception not supported by <fenv.h>", 

               GSL_EUNSUP);

#endif

    }

  if (exception_mask & GSL_IEEE_MASK_DENORMALIZED)

    {

      /* do nothing */

    }

  else

    {

      GSL_ERROR ("denormalized operand exception not supported by <fenv.h>. "

                 "Use 'mask-denormalized' to work around this.", GSL_EUNSUP) ;

    }

  if (exception_mask & GSL_IEEE_MASK_DIVISION_BY_ZERO)

    {

#ifdef FE_DIVBYZERO

      mode &= ~ FE_DIVBYZERO ;

#else

      GSL_ERROR ("division by zero exception not supported by <fenv.h>", 

                 GSL_EUNSUP);

#endif

    }

  if (exception_mask & GSL_IEEE_MASK_OVERFLOW)

    {

#ifdef FE_OVERFLOW

      mode &= ~ FE_OVERFLOW ;

#else

      GSL_ERROR ("overflow exception not supported by <fenv.h>", GSL_EUNSUP);

#endif

    }

  if (exception_mask & GSL_IEEE_MASK_UNDERFLOW)

    {

#ifdef FE_UNDERFLOW

      mode &=  ~ FE_UNDERFLOW ;

#else

      GSL_ERROR ("underflow exception not supported by <fenv.h>", GSL_EUNSUP);

#endif

    }

  if (exception_mask & GSL_IEEE_TRAP_INEXACT)

    {

#ifdef FE_INEXACT

      mode |= FE_INEXACT ;

#else

      GSL_ERROR ("inexact exception not supported by <fenv.h>", GSL_EUNSUP);

#endif

    }

  else

    {

#ifdef FE_INEXACT

      mode &= ~ FE_INEXACT ;

#else

      /* do nothing */

#endif

    }

#if HAVE_DECL_FEENABLEEXCEPT

  feenableexcept (mode) ;

#elif HAVE_DECL_FESETTRAPENABLE

  fesettrapenable (mode);

#else

  GSL_ERROR ("unknown exception trap method", GSL_EUNSUP)

#endif

  return GSL_SUCCESS ;

}