fpusetup.c

蒙特卡罗模拟光子成像C语言版,代码简洁专业

/***********************************************************************
 * If used, causes certain invalid mathematical operations to generate
 *  a SIGFPE and dump core rather than silently proceeding.  For 
 *  normal operation, this should never happen.  It is most useful,
 *  therefore, in tracking down subtle numerical bugs.
 *
 * If INHIBIT_FPU_CONTROL is defined or the OS is not ix86-linux,
 *  the function returns without changing anything.
 **********************************************************************/

/*
 * This file is part of tMCimg.
 * 
 * tMCimg 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 2 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.,
 * 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */


#include "config.h"

/* This can also be done through the GSL, save that for later */

#if (DO_FPU_CONTROL)
# if (HAVE_FPU_CONTROL_H)
#  include <fpu_control.h>
# else
#  error "FPU control requested but header file not found"
# endif
#endif

#if (DO_FPU_CONTROL)
void fpusetup(void)
{
  fpu_control_t fpu;

  _FPU_GETCW(fpu);

  /*
   * If not masked off (as is the default), these raise an interrupt
   * which gets turned into a SIGFPE by the C runtime libraries.
   *
   * _FPU_MASK_IM: Invalid operation mask
   * _FPU_MASK_DM: Denormalized operand mask
   * _FPU_MASK_ZM: Zero-divide mask
   * _FPU_MASK_OM: Overflow mask
   * _FPU_MASK_UM: Underflow mask
   * _FPU_MASK_PM: Precision (inexact result) mask
   */

  /* Take off some of the masks */
#if 0
  fpu &= ~(_FPU_MASK_IM | _FPU_MASK_ZM |
           _FPU_MASK_OM | _FPU_MASK_UM | _FPU_MASK_DM);
#else
  fpu &= ~(_FPU_MASK_IM | _FPU_MASK_ZM );
#endif
  fpu &= ~(_FPU_EXTENDED);
  fpu |= _FPU_DOUBLE;

  _FPU_SETCW(fpu);

  return;
}
#else                     /* !DO_FPU_CONTROL */
void fpusetup(void)
{
  /* Return without changing anything */

  return;
}
#endif