pspinlock.c 2.0 KB

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  1. /* POSIX spinlock implementation. hppa version.
  2. Copyright (C) 2000 Free Software Foundation, Inc.
  3. This file is part of the GNU C Library.
  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 License as
  6. published by the Free Software Foundation; either version 2.1 of the
  7. 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; see the file COPYING.LIB. If
  14. not, see <http://www.gnu.org/licenses/>. */
  15. #include <errno.h>
  16. #include <pthread.h>
  17. #include "internals.h"
  18. int
  19. __pthread_spin_lock (pthread_spinlock_t *lock)
  20. {
  21. unsigned int val;
  22. do
  23. __asm__ __volatile__ ("ldcw %1,%0"
  24. : "=r" (val), "=m" (*lock)
  25. : "m" (*lock));
  26. while (!val);
  27. return 0;
  28. }
  29. weak_alias (__pthread_spin_lock, pthread_spin_lock)
  30. int
  31. __pthread_spin_trylock (pthread_spinlock_t *lock)
  32. {
  33. unsigned int val;
  34. __asm__ __volatile__ ("ldcw %1,%0"
  35. : "=r" (val), "=m" (*lock)
  36. : "m" (*lock));
  37. return val ? 0 : EBUSY;
  38. }
  39. weak_alias (__pthread_spin_trylock, pthread_spin_trylock)
  40. int
  41. __pthread_spin_unlock (pthread_spinlock_t *lock)
  42. {
  43. *lock = 1;
  44. return 0;
  45. }
  46. weak_alias (__pthread_spin_unlock, pthread_spin_unlock)
  47. int
  48. __pthread_spin_init (pthread_spinlock_t *lock, int pshared)
  49. {
  50. /* We can ignore the `pshared' parameter. Since we are busy-waiting
  51. all processes which can access the memory location `lock' points
  52. to can use the spinlock. */
  53. *lock = 1;
  54. return 0;
  55. }
  56. weak_alias (__pthread_spin_init, pthread_spin_init)
  57. int
  58. __pthread_spin_destroy (pthread_spinlock_t *lock)
  59. {
  60. /* Nothing to do. */
  61. return 0;
  62. }
  63. weak_alias (__pthread_spin_destroy, pthread_spin_destroy)