/* Record the time the thread has been blocked. */int64_t ticks_blocked;

/*Set default ticks_blocked ＝ 0*/t->ticks_blocked = 0;

/* Sleeps for approximately TICKS timer ticks.  Interrupts mustbe turned on. */
void
timer_sleep (int64_t ticks)
{if (ticks <= 0){return;}ASSERT (intr_get_level () == INTR_ON);enum intr_level old_level = intr_disable ();struct thread *current_thread = thread_current ();current_thread->ticks_blocked = ticks;thread_block ();intr_set_level (old_level);
}

/* Puts the current thread to sleep.  It will not be scheduledagain until awoken by thread_unblock().This function must be called with interrupts turned off.  Itis usually a better idea to use one of the synchronizationprimitives in synch.h. */
void
thread_block (void)
{ASSERT (!intr_context ());ASSERT (intr_get_level () == INTR_OFF);thread_current ()->status = THREAD_BLOCKED;schedule ();
}

  thread_foreach (blocked_thread_check, NULL);

/* Invoke function 'func' on all threads, passing along 'aux'.This function must be called with interrupts off. */
void
thread_foreach (thread_action_func *func, void *aux)
{struct list_elem *e;ASSERT (intr_get_level () == INTR_OFF);for (e = list_begin (&all_list); e != list_end (&all_list);e = list_next (e)){struct thread *t = list_entry (e, struct thread, allelem);func (t, aux);}
}

void blocked_thread_check (struct thread *, void * UNUSED);

/* Check the blocked thread */
void
blocked_thread_check (struct thread *t, void *aux UNUSED)
{if (t->status == THREAD_BLOCKED && t->ticks_blocked > 0){t->ticks_blocked--;if (t->ticks_blocked == 0){thread_unblock(t);}}
}

/* Transitions a blocked thread T to the ready-to-run state.This is an error if T is not blocked.  (Use thread_yield() tomake the running thread ready.)This function does not preempt the running thread.  This canbe important: if the caller had disabled interrupts itself,it may expect that it can atomically unblock a thread andupdate other data. */
void
thread_unblock (struct thread *t)
{enum intr_level old_level;ASSERT (is_thread (t));old_level = intr_disable ();ASSERT (t->status == THREAD_BLOCKED);list_push_back (&ready_list, &t->elem);t->status = THREAD_READY;intr_set_level (old_level);
}