sem_trywait.S 1.4 KB

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  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, write to the Free
  14. Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  15. 02111-1307 USA. */
  16. #include <sysdep.h>
  17. #include <lowlevellock.h>
  18. #include <pthread-errnos.h>
  19. .text
  20. .globl sem_trywait
  21. .type sem_trywait,@function
  22. .align 16
  23. sem_trywait:
  24. movl (%rdi), %eax
  25. 2: testl %eax, %eax
  26. jz 1f
  27. leal -1(%rax), %edx
  28. LOCK
  29. cmpxchgl %edx, (%rdi)
  30. jne 2b
  31. xorl %eax, %eax
  32. retq
  33. 1:
  34. #if USE___THREAD
  35. movq errno@gottpoff(%rip), %rdx
  36. movl $EAGAIN, %fs:(%rdx)
  37. #else
  38. callq __errno_location@plt
  39. movl $EAGAIN, (%rax)
  40. #endif
  41. orl $-1, %eax
  42. retq
  43. .size sem_trywait,.-sem_trywait