52 lines
1.4 KiB
C
52 lines
1.4 KiB
C
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#ifndef THREADS_SYNCH_H
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#define THREADS_SYNCH_H
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#include <list.h>
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#include <stdbool.h>
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/* A counting semaphore. */
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struct semaphore
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{
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unsigned value; /* Current value. */
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struct list waiters; /* List of waiting threads. */
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};
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void sema_init (struct semaphore *, unsigned value);
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void sema_down (struct semaphore *);
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bool sema_try_down (struct semaphore *);
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void sema_up (struct semaphore *);
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void sema_self_test (void);
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/* Lock. */
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struct lock
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{
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struct thread *holder; /* Thread holding lock (for debugging). */
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struct semaphore semaphore; /* Binary semaphore controlling access. */
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};
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void lock_init (struct lock *);
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void lock_acquire (struct lock *);
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bool lock_try_acquire (struct lock *);
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void lock_release (struct lock *);
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bool lock_held_by_current_thread (const struct lock *);
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/* Condition variable. */
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struct condition
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{
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struct list waiters; /* List of waiting threads. */
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};
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void cond_init (struct condition *);
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void cond_wait (struct condition *, struct lock *);
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void cond_signal (struct condition *, struct lock *);
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void cond_broadcast (struct condition *, struct lock *);
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/* Optimization barrier.
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The compiler will not reorder operations across an
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optimization barrier. See "Optimization Barriers" in the
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reference guide for more information.*/
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#define barrier() asm volatile ("" : : : "memory")
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#endif /* threads/synch.h */
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