thread_init

/* Initializes the threading system by transforming the code
   that's currently running into a thread.  This can't work in
   general and it is possible in this case only because loader.S
   was careful to put the bottom of the stack at a page boundary.

   Also initializes the run queue and the tid lock.

   After calling this function, be sure to initialize the page
   allocator before trying to create any threads with
   thread_create().

   It is not safe to call thread_current() until this function
   finishes. */
void
thread_init(void) {
    ASSERT (intr_get_level() == INTR_OFF);

    lock_init(&tid_lock);
    list_init(&ready_list);
    list_init(&all_list);
    list_init(&sleep_list);
    sema_init(&sleep_semaphore, 1);

    /* Set up a thread structure for the running thread. */
    initial_thread = running_thread();
    init_thread(initial_thread, "main", PRI_DEFAULT);
    initial_thread->status = THREAD_RUNNING;
    initial_thread->tid = allocate_tid();

    /* Initializing "load_avg_const1", "load_avg_const2", then "load_avg" of the system for MLFQ Scheduler */
    load_avg_const1 = divide_int(convert_to_fixed(ALPHA), BETA);
    load_avg_const2 = divide_int(convert_to_fixed(ZETA), BETA);
    load_avg = convert_to_fixed(0);
}