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atomic.h
Package: linux-2.4.20.tar.gz　[view]
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Upload Date: 2013-04-10
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Linux-Unix program

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Unix_Linux

atomic.h：Code Content
  1. #ifndef __ASM_SH_ATOMIC_H
  2. #define __ASM_SH_ATOMIC_H
  4. /*
  5.  * Atomic operations that C can't guarantee us.  Useful for
  6.  * resource counting etc..
  7.  *
  8.  */
  10. typedef struct { volatile int counter; } atomic_t;
  12. #define ATOMIC_INIT(i) ( (atomic_t) { (i) } )
  14. #define atomic_read(v) ((v)->counter)
  15. #define atomic_set(v,i) ((v)->counter = (i))
  17. #include <asm/system.h>
  19. /*
  20.  * To get proper branch prediction for the main line, we must branch
  21.  * forward to code at the end of this object's .text section, then
  22.  * branch back to restart the operation.
  23.  */
  25. static __inline__ void atomic_add(int i, atomic_t * v)
  26. {
  27. unsigned long flags;
  29. save_and_cli(flags);
  30. *(long *)v += i;
  31. restore_flags(flags);
  32. }
  34. static __inline__ void atomic_sub(int i, atomic_t *v)
  35. {
  36. unsigned long flags;
  38. save_and_cli(flags);
  39. *(long *)v -= i;
  40. restore_flags(flags);
  41. }
  43. static __inline__ int atomic_add_return(int i, atomic_t * v)
  44. {
  45. unsigned long temp, flags;
  47. save_and_cli(flags);
  48. temp = *(long *)v;
  49. temp += i;
  50. *(long *)v = temp;
  51. restore_flags(flags);
  53. return temp;
  54. }
  56. static __inline__ int atomic_sub_return(int i, atomic_t * v)
  57. {
  58. unsigned long temp, flags;
  60. save_and_cli(flags);
  61. temp = *(long *)v;
  62. temp -= i;
  63. *(long *)v = temp;
  64. restore_flags(flags);
  66. return temp;
  67. }
  69. #define atomic_dec_return(v) atomic_sub_return(1,(v))
  70. #define atomic_inc_return(v) atomic_add_return(1,(v))
  72. #define atomic_sub_and_test(i,v) (atomic_sub_return((i), (v)) == 0)
  73. #define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
  75. #define atomic_inc(v) atomic_add(1,(v))
  76. #define atomic_dec(v) atomic_sub(1,(v))
  78. static __inline__ void atomic_clear_mask(unsigned int mask, atomic_t *v)
  79. {
  80. unsigned long flags;
  82. save_and_cli(flags);
  83. *(long *)v &= ~mask;
  84. restore_flags(flags);
  85. }
  87. static __inline__ void atomic_set_mask(unsigned int mask, atomic_t *v)
  88. {
  89. unsigned long flags;
  91. save_and_cli(flags);
  92. *(long *)v |= mask;
  93. restore_flags(flags);
  94. }
  96. /* Atomic operations are already serializing on SH */
  97. #define smp_mb__before_atomic_dec() barrier()
  98. #define smp_mb__after_atomic_dec() barrier()
  99. #define smp_mb__before_atomic_inc() barrier()
  100. #define smp_mb__after_atomic_inc() barrier()
  102. #endif /* __ASM_SH_ATOMIC_H */