// func is a pointer to a procedure the thread will run.
// arg is the argument to be passed to that procedure.
void 
thread_create(thread_t *thread, void (*func)(int), int arg) {
    // Allocate TCB and stack 
    TCB *tcb = new TCB();

    thread->tcb = tcb;
    tcb->stack_size = INITIAL_STACK_SIZE;
    tcb->stack = new Stack(INITIAL_STACK_SIZE);

    // Initialize registers so that when thread is resumed, it will start running at  
    // stub.  The stack starts at the top of the allocated region and grows down.
    tcb->sp = tcb->stack + INITIAL_STACK_SIZE; 
    tcb->pc = stub;     

    // Create a stack frame by pushing stub's arguments and start address 
    // onto the stack: func, arg
    *(tcb->sp) = arg;       
    tcb->sp--;
    *(tcb->sp) = func;          
    tcb->sp--;
  
    // Create another stack frame so that thread_switch works correctly.
    // This routine is explained later in the chapter.
    thread_dummySwitchFrame(tcb);

    tcb->state = #\readyThreadState#;
    readyList.add(tcb);    // Put tcb on ready list
}

void
stub(void (*func)(int), int arg) {
    (*func)(arg);           // Execute the function func()
    thread_exit(0);         // If func() does not call exit,  call it here.
}