sysdeps/i386/fpu/fegetenv.c

   1 /* Store current floating-point environment.
   2    Copyright (C) 1997-2024 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.h>
  20 #include <unistd.h>
  21 #include <ldsodefs.h>
  22 #include <dl-procinfo.h>
  23
  24 int
  25 __fegetenv (fenv_t *envp)
  26 {
  27   __asm__ ("fnstenv %0" : "=m" (*envp));
  28   /* And load it right back since the processor changes the mask.
  29      Intel thought this opcode to be used in interrupt handlers which
  30      would block all exceptions.  */
  31   __asm__ ("fldenv %0" : : "m" (*envp));
  32
  33   if (CPU_FEATURE_USABLE (SSE))
  34     __asm__ ("stmxcsr %0" : "=m" (envp->__eip));
  35
  36   /* Success.  */
  37   return 0;
  38 }
  39
  40 #include <shlib-compat.h>
  41 #if SHLIB_COMPAT (libm, GLIBC_2_1, GLIBC_2_2)
  42 strong_alias (__fegetenv, __old_fegetenv)
  43 compat_symbol (libm, __old_fegetenv, fegetenv, GLIBC_2_1);
  44 #endif
  45
  46 libm_hidden_def (__fegetenv)
  47 libm_hidden_ver (__fegetenv, fegetenv)
  48 versioned_symbol (libm, __fegetenv, fegetenv, GLIBC_2_2);