vfork.S 1.6 KB

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  1. /* Copyright (C) 2004 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. Contributed by Jakub Jelinek <jakub@redhat.com>, 2004.
  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. #define _ERRNO_H 1
  17. #include <bits/errno.h>
  18. #include <bits/kernel-features.h>
  19. #include <tcb-offsets.h>
  20. /* Clone the calling process, but without copying the whole address space.
  21. The calling process is suspended until the new process exits or is
  22. replaced by a call to `execve'. Return -1 for errors, 0 to the new process,
  23. and the process ID of the new process to the old process. */
  24. ENTRY (__vfork)
  25. lwz 0,PID(2)
  26. cmpwi 0,0,0
  27. neg 0,0
  28. bne- 0,1f
  29. lis 0,0x8000
  30. 1: stw 0,PID(2)
  31. DO_CALL (SYS_ify (vfork))
  32. cmpwi 1,3,0
  33. beqlr- 1
  34. lwz 0,PID(2)
  35. /* Cannot use clrlwi. here, because cr0 needs to be preserved
  36. until PSEUDO_RET. */
  37. clrlwi 4,0,1
  38. cmpwi 1,4,0
  39. beq- 1,1f
  40. neg 4,0
  41. 1: stw 4,PID(2)
  42. PSEUDO_RET
  43. PSEUDO_END (__vfork)
  44. libc_hidden_def (__vfork)
  45. weak_alias (__vfork, vfork)
  46. libc_hidden_weak(vfork)