atomicity.h 1.8 KB

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  1. /* Low-level functions for atomic operations. ix86 version, x >= 4.
  2. Copyright (C) 1997, 2000, 2001 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
  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. #ifndef _ATOMICITY_H
  17. #define _ATOMICITY_H 1
  18. #include <inttypes.h>
  19. static inline uint32_t
  20. __attribute_used__
  21. exchange_and_add (volatile uint32_t *mem, uint32_t val)
  22. {
  23. register uint32_t result;
  24. __asm__ __volatile__ ("lock; xaddl %0,%1"
  25. : "=r" (result), "=m" (*mem) : "0" (val), "1" (*mem));
  26. return result;
  27. }
  28. static inline void
  29. __attribute_used__
  30. atomic_add (volatile uint32_t *mem, int val)
  31. {
  32. __asm__ __volatile__ ("lock; addl %1,%0"
  33. : "=m" (*mem) : "ir" (val), "0" (*mem));
  34. }
  35. static inline char
  36. __attribute_used__
  37. compare_and_swap (volatile long int *p, long int oldval, long int newval)
  38. {
  39. char ret;
  40. long int readval;
  41. __asm__ __volatile__ ("lock; cmpxchgl %3, %1; sete %0"
  42. : "=q" (ret), "=m" (*p), "=a" (readval)
  43. : "r" (newval), "1" (*p), "a" (oldval));
  44. return ret;
  45. }
  46. #endif /* atomicity.h */