sysdeps/s390/fpu/fsetexcptflg.c

   1 /* Set floating-point environment exception handling.
   2    Copyright (C) 2000-2019 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Denis Joseph Barrow (djbarrow@de.ibm.com).
   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, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <fenv_libc.h>
  21 #include <math.h>
  22 #include <fpu_control.h>
  23
  24 int
  25 fesetexceptflag (const fexcept_t *flagp, int excepts)
  26 {
  27   fexcept_t temp, newexcepts;
  28
  29   /* Get the current environment.  We have to do this since we cannot
  30      separately set the status word.  */
  31   _FPU_GETCW (temp);
  32   /* Install the new exception bits in the Accrued Exception Byte.  */
  33   excepts = excepts & FE_ALL_EXCEPT;
  34   newexcepts = excepts << FPC_FLAGS_SHIFT;
  35   temp &= ~newexcepts;
  36   if ((temp & FPC_NOT_FPU_EXCEPTION) == 0)
  37     /* Bits 6, 7 of dxc-byte are zero,
  38        thus bits 0-5 of dxc-byte correspond to the flag-bits.
  39        Clear given exceptions in dxc-field.  */
  40     temp &= ~(excepts << FPC_DXC_SHIFT);
  41
  42   /* Integrate dxc-byte of flagp into flags. The dxc-byte of flagp contains
  43      either an ieee-exception or 0 (see fegetexceptflag).  */
  44   temp |= (*flagp | ((*flagp >> FPC_DXC_SHIFT) << FPC_FLAGS_SHIFT))
  45     & newexcepts;
  46
  47   /* Store the new status word (along with the rest of the environment.
  48      Possibly new exceptions are set but they won't get executed.  */
  49   _FPU_SETCW (temp);
  50
  51   /* Success.  */
  52   return 0;
  53 }