feholdexcpt.c

来自「Glibc 2.3.2源代码(解压后有100多M)」· C语言 代码 · 共 40 行

/* Store current floating-point environment and clear exceptions.
   Copyright (C) 1997, 1999 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Andreas Schwab <[e-mail]>

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <fenv.h>

int
feholdexcept (fenv_t *envp)
{
  fexcept_t fpcr, fpsr;

  /* Store the environment.  */
  __asm__ ("fmovem%.l %/fpcr/%/fpsr/%/fpiar,%0" : "=m" (*envp));

  /* Now clear all exceptions.  */
  fpsr = envp->__status_register & ~FE_ALL_EXCEPT;
  __asm__ __volatile__ ("fmove%.l %0,%/fpsr" : : "dm" (fpsr));
  /* And set all exceptions to non-stop.  */
  fpcr = envp->__control_register & ~(FE_ALL_EXCEPT << 6);
  __asm__ __volatile__ ("fmove%.l %0,%!" : : "dm" (fpcr));

  return 0;
}