sysdeps/alpha/fpu/fesetenv.c

   1 /* Install given floating-point environment.
   2    Copyright (C) 1997,99,2000,01,02 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Richard Henderson <rth@tamu.edu>, 1997
   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, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <fenv_libc.h>
  22
  23 int
  24 __fesetenv (const fenv_t *envp)
  25 {
  26   unsigned long int fpcr;
  27   fenv_t env;
  28
  29   /* Magic encoding of default values: high bit set (never possible for a
  30      user-space address) is not indirect.  And we don't even have to get
  31      rid of it since we mask things around just below.  */
  32   if ((long int) envp >= 0)
  33     env = *envp;
  34   else
  35     env = (unsigned long int) envp;
  36
  37   /* Reset the rounding mode with the hardware fpcr.  Note that the following
  38      system call is an implied trap barrier for our modification.  */
  39   __asm__ __volatile__ ("excb; mf_fpcr %0" : "=f" (fpcr));
  40   fpcr = (fpcr & ~FPCR_ROUND_MASK) | (env & FPCR_ROUND_MASK);
  41   __asm__ __volatile__ ("mt_fpcr %0" : : "f" (fpcr));
  42
  43   /* Reset the exception status and mask with the kernel's FP code.  */
  44   __ieee_set_fp_control (env & SWCR_ALL_MASK);
  45
  46   /* Success.  */
  47   return 0;
  48 }
  49
  50 #include <shlib-compat.h>
  51 #if SHLIB_COMPAT (libm, GLIBC_2_1, GLIBC_2_2)
  52 strong_alias (__fesetenv, __old_fesetenv)
  53 compat_symbol (libm, __old_fesetenv, fesetenv, GLIBC_2_1);
  54 #endif
  55
  56 libm_hidden_ver (__fesetenv, fesetenv)
  57 versioned_symbol (libm, __fesetenv, fesetenv, GLIBC_2_2);