sysdeps/powerpc/powerpc32/e500/nofpu/atomic-feholdexcept.c

   1 /* Store current floating-point environment and clear exceptions for
   2    atomic compound assignment.  e500 version.
   3    Copyright (C) 2004-2014 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library.  If not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <fenv_libc.h>
  21 #include <stdlib.h>
  22 #include <sysdep.h>
  23 #include <sys/prctl.h>
  24
  25 void
  26 __atomic_feholdexcept (fenv_t *envp)
  27 {
  28   fenv_union_t u;
  29   INTERNAL_SYSCALL_DECL (err);
  30   int r;
  31
  32   /* Get the current state.  */
  33   r = INTERNAL_SYSCALL (prctl, err, 2, PR_GET_FPEXC, &u.l[0]);
  34   if (INTERNAL_SYSCALL_ERROR_P (r, err))
  35     abort ();
  36
  37   u.l[1] = fegetenv_register ();
  38   *envp = u.fenv;
  39
  40   /* Clear everything except for the rounding mode and trapping to the
  41      kernel.  */
  42   u.l[0] &= ~(PR_FP_EXC_DIV
  43               | PR_FP_EXC_OVF
  44               | PR_FP_EXC_UND
  45               | PR_FP_EXC_RES
  46               | PR_FP_EXC_INV);
  47   u.l[1] &= SPEFSCR_FRMC | (SPEFSCR_ALL_EXCEPT_ENABLE & ~SPEFSCR_FINXE);
  48
  49   /* Put the new state in effect.  */
  50   fesetenv_register (u.l[1]);
  51   r = INTERNAL_SYSCALL (prctl, err, 2, PR_SET_FPEXC,
  52                         u.l[0] | PR_FP_EXC_SW_ENABLE);
  53   if (INTERNAL_SYSCALL_ERROR_P (r, err))
  54     abort ();
  55 }