feenablxcpt.c

来自「Glibc 2.3.2源代码(解压后有100多M)」· C语言 代码 · 共 56 行

/* Enable floating-point exceptions.
   Copyright (C) 2000 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Geoffrey Keating <[e-mail]>, 2000.

   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_libc.h>

int
feenableexcept (int excepts)
{
  fenv_union_t fe;
  int result, new;

  result = fegetexcept ();

  if ((excepts & FE_ALL_INVALID) == FE_ALL_INVALID)
    excepts = (excepts | FE_INVALID) & ~ FE_ALL_INVALID;

  fe.fenv = fegetenv_register ();
  if (excepts & FE_INEXACT)
    fe.l[1] |= (1 << (31 - FPSCR_XE));
  if (excepts & FE_DIVBYZERO)
    fe.l[1] |= (1 << (31 - FPSCR_ZE));
  if (excepts & FE_UNDERFLOW)
    fe.l[1] |= (1 << (31 - FPSCR_UE));
  if (excepts & FE_OVERFLOW)
    fe.l[1] |= (1 << (31 - FPSCR_OE));
  if (excepts & FE_INVALID)
    fe.l[1] |= (1 << (31 - FPSCR_VE));
  fesetenv_register (fe.fenv);

  new = fegetexcept ();
  if (new != 0 && result == 0)
    (void)__fe_nomask_env ();

  if ((new & excepts) != excepts)
    result = -1;

  return result;
}