sem_trywait.S 1.3 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051
  1. /* Copyright (C) 2002, 2003, 2005, 2007 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
  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 <sysdep.h>
  16. #include <lowlevellock.h>
  17. #include <pthread-errnos.h>
  18. .text
  19. .globl sem_trywait
  20. .type sem_trywait,@function
  21. .align 16
  22. sem_trywait:
  23. movl (%rdi), %eax
  24. 2: testl %eax, %eax
  25. jz 1f
  26. leal -1(%rax), %edx
  27. LOCK
  28. cmpxchgl %edx, (%rdi)
  29. jne 2b
  30. xorl %eax, %eax
  31. retq
  32. 1:
  33. #if USE___THREAD
  34. movq errno@gottpoff(%rip), %rdx
  35. movl $EAGAIN, %fs:(%rdx)
  36. #else
  37. callq __errno_location@plt
  38. movl $EAGAIN, (%rax)
  39. #endif
  40. orl $-1, %eax
  41. retq
  42. .size sem_trywait,.-sem_trywait