sysdeps/powerpc/fpu/fesetenv.c

   1 /* Install given floating-point environment.
   2    Copyright (C) 1997-2015 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <fenv_libc.h>
  20 #include <fpu_control.h>
  21
  22 #define _FPU_MASK_ALL (_FPU_MASK_ZM | _FPU_MASK_OM | _FPU_MASK_UM | _FPU_MASK_XM | _FPU_MASK_IM)
  23
  24 int
  25 __fesetenv (const fenv_t *envp)
  26 {
  27   fenv_union_t old, new;
  28
  29   /* get the currently set exceptions.  */
  30   new.fenv = *envp;
  31   old.fenv = fegetenv_register ();
  32   if (old.l == new.l)
  33     return 0;
  34
  35   /* If the old env has no enabled exceptions and the new env has any enabled
  36      exceptions, then unmask SIGFPE in the MSR FE0/FE1 bits.  This will put the
  37      hardware into "precise mode" and may cause the FPU to run slower on some
  38      hardware.  */
  39   if ((old.l & _FPU_MASK_ALL) == 0 && (new.l & _FPU_MASK_ALL) != 0)
  40     (void) __fe_nomask_env_priv ();
  41
  42   /* If the old env had any enabled exceptions and the new env has no enabled
  43      exceptions, then mask SIGFPE in the MSR FE0/FE1 bits.  This may allow the
  44      FPU to run faster because it always takes the default action and can not
  45      generate SIGFPE. */
  46   if ((old.l & _FPU_MASK_ALL) != 0 && (new.l & _FPU_MASK_ALL) == 0)
  47     (void)__fe_mask_env ();
  48
  49   fesetenv_register (*envp);
  50
  51   /* Success.  */
  52   return 0;
  53 }
  54
  55 #include <shlib-compat.h>
  56 #if SHLIB_COMPAT (libm, GLIBC_2_1, GLIBC_2_2)
  57 strong_alias (__fesetenv, __old_fesetenv)
  58 compat_symbol (libm, __old_fesetenv, fesetenv, GLIBC_2_1);
  59 #endif
  60
  61 libm_hidden_ver (__fesetenv, fesetenv)
  62 versioned_symbol (libm, __fesetenv, fesetenv, GLIBC_2_2);