glibc/sysdeps/unix/sysv/linux/powerpc/fe_nomask.c

/* Procedure definition for FE_NOMASK_ENV for Linux/ppc.
   Copyright (C) 2000 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   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>
#include <errno.h>
#include <signal.h>
#include <unistd.h>

/* This is rather fiddly under Linux.  We don't have direct access,
   and there is no system call, but we can change the bits 
   in a signal handler's context...  */

static struct sigaction oact;

static void
fe_nomask_handler (int signum, struct sigcontext *sc)
{
  sc->regs->msr |= 0x900ul;  /* FE0 | FE1 */
  sigaction (SIGUSR1, &oact, NULL);
}

const fenv_t *
__fe_nomask_env(void)
{
  struct sigaction act;

  act.sa_handler = (sighandler_t) fe_nomask_handler;
  sigemptyset (&act.sa_mask);
  act.sa_flags = 0;

  sigaction (SIGUSR1, &act, &oact);
  raise (SIGUSR1);

  return FE_ENABLED_ENV;
}