135 lines
2.9 KiB
C
Executable File
135 lines
2.9 KiB
C
Executable File
//Source: http://golubenco.org/atomic-operations.html
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#ifndef _GENERIC_ATOMIC_H
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#define _GENERIC_ATOMIC_H
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/* Check GCC version, just to be safe */
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#if !defined(__GNUC__) || (__GNUC__ < 4) || (__GNUC_MINOR__ < 1)
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# error atomic.h works only with GCC newer than version 4.1
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#endif /* GNUC >= 4.1 */
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/**
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* Atomic type.
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*/
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typedef struct {
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volatile int counter;
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} atomic_t;
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#define ATOMIC_INIT(i) { (i) }
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/**
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* Read atomic variable
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* @param v pointer of type atomic_t
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*
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* Atomically reads the value of @v.
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*/
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#define atomic_read(v) ((v)->counter)
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/**
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* Set atomic variable
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* @param v pointer of type atomic_t
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* @param i required value
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*/
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#define atomic_set(v,i) (((v)->counter) = (i))
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/**
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* Add to the atomic variable
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* @param i integer value to add
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* @param v pointer of type atomic_t
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*/
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static inline void atomic_add( int i, atomic_t *v )
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{
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(void)__sync_add_and_fetch(&v->counter, i);
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}
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/**
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* Subtract the atomic variable
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* @param i integer value to subtract
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* @param v pointer of type atomic_t
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*
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* Atomically subtracts @i from @v.
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*/
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static inline void atomic_sub( int i, atomic_t *v )
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{
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(void)__sync_sub_and_fetch(&v->counter, i);
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}
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/**
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* Subtract value from variable and test result
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* @param i integer value to subtract
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* @param v pointer of type atomic_t
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*
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* Atomically subtracts @i from @v and returns
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* true if the result is zero, or false for all
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* other cases.
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*/
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static inline int atomic_sub_and_test( int i, atomic_t *v )
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{
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return !(__sync_sub_and_fetch(&v->counter, i));
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}
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/**
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* Increment atomic variable
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* @param v pointer of type atomic_t
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*
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* Atomically increments @v by 1.
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*/
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static inline void atomic_inc( atomic_t *v )
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{
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(void)__sync_fetch_and_add(&v->counter, 1);
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}
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/**
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* @brief decrement atomic variable
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* @param v: pointer of type atomic_t
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*
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* Atomically decrements @v by 1. Note that the guaranteed
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* useful range of an atomic_t is only 24 bits.
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*/
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static inline void atomic_dec( atomic_t *v )
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{
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(void)__sync_fetch_and_sub(&v->counter, 1);
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}
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/**
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* @brief Decrement and test
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* @param v pointer of type atomic_t
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*
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* Atomically decrements @v by 1 and
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* returns true if the result is 0, or false for all other
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* cases.
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*/
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static inline int atomic_dec_and_test( atomic_t *v )
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{
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return !(__sync_sub_and_fetch(&v->counter, 1));
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}
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/**
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* @brief Increment and test
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* @param v pointer of type atomic_t
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*
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* Atomically increments @v by 1
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* and returns true if the result is zero, or false for all
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* other cases.
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*/
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static inline int atomic_inc_and_test( atomic_t *v )
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{
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return !(__sync_add_and_fetch(&v->counter, 1));
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}
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/**
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* @brief add and test if negative
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* @param v pointer of type atomic_t
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* @param i integer value to add
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*
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* Atomically adds @i to @v and returns true
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* if the result is negative, or false when
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* result is greater than or equal to zero.
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*/
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static inline int atomic_add_negative( int i, atomic_t *v )
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{
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return (__sync_add_and_fetch(&v->counter, i) < 0);
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}
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#endif
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