feenablxcpt.c 1.4 KB

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  1. /* Enable floating-point exceptions.
  2. Copyright (C) 2001-2017 Free Software Foundation, Inc.
  3. Contributed by Andreas Jaeger <aj@suse.de>, 2001.
  4. The GNU C Library is free software; you can redistribute it and/or
  5. modify it under the terms of the GNU Lesser General Public
  6. License as published by the Free Software Foundation; either
  7. version 2.1 of the License, or (at your option) any later version.
  8. The GNU C Library is distributed in the hope that it will be useful,
  9. but WITHOUT ANY WARRANTY; without even the implied warranty of
  10. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11. Lesser General Public License for more details.
  12. You should have received a copy of the GNU Lesser General Public
  13. License along with the GNU C Library; if not, see
  14. <http://www.gnu.org/licenses/>. */
  15. #include <fenv.h>
  16. int
  17. feenableexcept (int excepts)
  18. {
  19. unsigned short int new_exc, old_exc;
  20. unsigned int new;
  21. excepts &= FE_ALL_EXCEPT;
  22. /* Get the current control word of the x87 FPU. */
  23. __asm__ ("fstcw %0" : "=m" (*&new_exc));
  24. old_exc = (~new_exc) & FE_ALL_EXCEPT;
  25. new_exc &= ~excepts;
  26. __asm__ ("fldcw %0" : : "m" (*&new_exc));
  27. /* And now the same for the SSE MXCSR register. */
  28. __asm__ ("stmxcsr %0" : "=m" (*&new));
  29. /* The SSE exception masks are shifted by 7 bits. */
  30. new &= ~(excepts << 7);
  31. __asm__ ("ldmxcsr %0" : : "m" (*&new));
  32. return old_exc;
  33. }