/* ieee-utils/fp-os2.c

 * 

 * Copyright (C) 2001 Henry Sobotka <sobotka@axess.com>

 * 

 * 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.

 */

#include <float.h>

#include <gsl/gsl_ieee_utils.h>

#include <gsl/gsl_errno.h>

int

gsl_ieee_set_mode (int precision, int rounding, int exception_mask)

{

  unsigned mode = 0;

  switch (precision)

    {

    case GSL_IEEE_SINGLE_PRECISION:

      _control87(PC_24, MCW_PC);    

      break ;

    case GSL_IEEE_DOUBLE_PRECISION:

      _control87(PC_53, MCW_PC);

      break ;

    case GSL_IEEE_EXTENDED_PRECISION:

      _control87(PC_64, MCW_PC);

      break ;

    }

  switch (rounding)

    {

    case GSL_IEEE_ROUND_TO_NEAREST:

      _control87(RC_NEAR, MCW_RC);

      break ;

    case GSL_IEEE_ROUND_DOWN:

      _control87(RC_DOWN, MCW_RC);

      break ;

    case GSL_IEEE_ROUND_UP:

      _control87(RC_UP, MCW_RC);

      break ;

    case GSL_IEEE_ROUND_TO_ZERO:

      _control87(RC_CHOP, MCW_RC);

      break ;

    default:

      _control87(RC_NEAR, MCW_RC);

    }

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

  mode = EM_INVALID | EM_DENORMAL | EM_ZERODIVIDE | EM_OVERFLOW | EM_UNDERFLOW;

  if (exception_mask & GSL_IEEE_MASK_INVALID)

    mode &= ~ EM_INVALID;

  if (exception_mask & GSL_IEEE_MASK_DENORMALIZED)

    mode &= ~ EM_DENORMAL;

  if (exception_mask & GSL_IEEE_MASK_DIVISION_BY_ZERO)

    mode &= ~ EM_ZERODIVIDE;

  if (exception_mask & GSL_IEEE_MASK_OVERFLOW)

    mode &= ~ EM_OVERFLOW;

  if (exception_mask & GSL_IEEE_MASK_UNDERFLOW)

    mode &= ~ EM_UNDERFLOW;

  if (exception_mask & GSL_IEEE_TRAP_INEXACT)

    {

      mode |= EM_INEXACT;

    }

  else

    {

      mode &= ~ EM_INEXACT;

    }

  _control87(mode, MCW_EM);

  return GSL_SUCCESS ;

}