sysdeps/aarch64/fpu/fesetenv.c

   1 /* Copyright (C) 1997-2015 Free Software Foundation, Inc.
   2
   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 License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    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.h>
  20 #include <fpu_control.h>
  21
  22 int
  23 fesetenv (const fenv_t *envp)
  24 {
  25   fpu_control_t fpcr;
  26   fpu_control_t fpcr_new;
  27   fpu_control_t updated_fpcr;
  28   fpu_fpsr_t fpsr;
  29   fpu_fpsr_t fpsr_new;
  30
  31   _FPU_GETCW (fpcr);
  32   _FPU_GETFPSR (fpsr);
  33
  34   fpcr_new = fpcr & _FPU_RESERVED;
  35   fpsr_new = fpsr & _FPU_FPSR_RESERVED;
  36
  37   if (envp == FE_DFL_ENV)
  38     {
  39       fpcr_new |= _FPU_DEFAULT;
  40       fpsr_new |= _FPU_FPSR_DEFAULT;
  41     }
  42   else if (envp == FE_NOMASK_ENV)
  43     {
  44       fpcr_new |= _FPU_FPCR_IEEE;
  45       fpsr_new |= _FPU_FPSR_IEEE;
  46     }
  47   else
  48     {
  49       fpcr_new |= envp->__fpcr & ~_FPU_RESERVED;
  50       fpsr_new |= envp->__fpsr & ~_FPU_FPSR_RESERVED;
  51     }
  52
  53   if (fpsr != fpsr_new)
  54     _FPU_SETFPSR (fpsr_new);
  55
  56   if (fpcr != fpcr_new)
  57     _FPU_SETCW (fpcr_new);
  58
  59   /* Trapping exceptions are optional in AArch64 the relevant enable
  60      bits in FPCR are RES0 hence the absence of support can be
  61      detected by reading back the FPCR and comparing with the required
  62      value.  */
  63
  64   _FPU_GETCW (updated_fpcr);
  65   if ((updated_fpcr & fpcr_new) != fpcr_new)
  66     return 1;
  67
  68   return 0;
  69 }
  70 libm_hidden_def (fesetenv)