/* This file is part of SIS (SPARC instruction simulator)

   Copyright (C) 1995-2017 Free Software Foundation, Inc.
   Contributed by Jiri Gaisler, European Space Agency

   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, see <http://www.gnu.org/licenses/>.  */

/* This file implements the interface between the host and the simulated
   FPU.  IEEE trap handling is done as follows:
     1. In the host, all IEEE traps are masked
     2. After each simulated FPU instruction, check if any exception
        occured by reading the exception bits from the host FPU status
        register (get_accex()).
     3. Propagate any exceptions to the simulated FSR.
     4. Clear host exception bits.
 */

#include "config.h"
#include "sis.h"
#include <fenv.h>

/* This routine should return the accrued exceptions */
int
get_accex ()
{
  int fexc, accx;

  fexc = fetestexcept (FE_ALL_EXCEPT);
  accx = 0;
  if (fexc & FE_INEXACT)
    accx |= 1;
  if (fexc & FE_DIVBYZERO)
    accx |= 2;
  if (fexc & FE_UNDERFLOW)
    accx |= 4;
  if (fexc & FE_OVERFLOW)
    accx |= 8;
  if (fexc & FE_INVALID)
    accx |= 0x10;
  return accx;
}

/* How to clear the accrued exceptions */
void
clear_accex ()
{
  feclearexcept (FE_ALL_EXCEPT);
}

/* How to map SPARC FSR onto the host */
void
set_fsr (fsr)
     uint32 fsr;
{
  int fround;

  fsr >>= 30;
  switch (fsr)
    {
    case 0:
      fround = FE_TONEAREST;
      break;
    case 1:
      fround = FE_TOWARDZERO;
      break;
    case 2:
      fround = FE_UPWARD;
      break;
    case 3:
      fround = FE_DOWNWARD;
      break;
    }
  fesetround (fround);
}