sysdeps/alpha/fpu/fesetenv.c

   1 /* Install given floating-point environment.
   2    Copyright (C) 1997-2023 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    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <fenv_libc.h>
  20
  21 int
  22 __fesetenv (const fenv_t *envp)
  23 {
  24   unsigned long int fpcr;
  25   fenv_t env;
  26
  27   /* Magic encoding of default values: high bit set (never possible for a
  28      user-space address) is not indirect.  And we don't even have to get
  29      rid of it since we mask things around just below.  */
  30   if ((long int) envp >= 0)
  31     env = *envp;
  32   else
  33     env = (unsigned long int) envp;
  34
  35   /* Reset the rounding mode with the hardware fpcr.  Note that the following
  36      system call is an implied trap barrier for our modification.  */
  37   __asm__ __volatile__ ("excb; mf_fpcr %0" : "=f" (fpcr));
  38   fpcr = (fpcr & ~FPCR_ROUND_MASK) | (env & FPCR_ROUND_MASK);
  39   __asm__ __volatile__ ("mt_fpcr %0" : : "f" (fpcr));
  40
  41   /* Reset the exception status and mask with the kernel's FP code.  */
  42   __ieee_set_fp_control (env & SWCR_ALL_MASK);
  43
  44   /* Success.  */
  45   return 0;
  46 }
  47
  48 #include <shlib-compat.h>
  49 #if SHLIB_COMPAT (libm, GLIBC_2_1, GLIBC_2_2)
  50 strong_alias (__fesetenv, __old_fesetenv)
  51 compat_symbol (libm, __old_fesetenv, fesetenv, GLIBC_2_1);
  52 #endif
  53
  54 libm_hidden_def (__fesetenv)
  55 libm_hidden_ver (__fesetenv, fesetenv)
  56 versioned_symbol (libm, __fesetenv, fesetenv, GLIBC_2_2);