1.RT-Thread内核剖析-----RTT启动流程

; Reset handler
Reset_Handler   PROC
                EXPORT  Reset_Handler             [WEAK]
                IMPORT  __main
                IMPORT  SystemInit
                LDR     R0, =SystemInit 
                BLX     R0   
                LDR     R0, =__main  
                BX      R0
                ENDP

int $Sub$$main(void)
{
    rt_hw_interrupt_disable(); //关闭所有中断，防止影响 RTT 操作系统初始化
    rtthread_startup();        //RTT 操作系统初始化
    return 0;
}

int rtthread_startup(void)
{
    rt_hw_interrupt_disable();

    /* board level initalization
     * NOTE: please initialize heap inside board initialization.
     */
    rt_hw_board_init();

    /* show RT-Thread version */
    rt_show_version();

    /* timer system initialization */
    rt_system_timer_init();

    /* scheduler system initialization */
    /* 1.初始化各优先级的线程链表
             2.初始化僵尸线程链表
             3.初始化当前线程为空
             4.初始化当前线程优先级为31，即MAX-1*/
    rt_system_scheduler_init();

#ifdef RT_USING_SIGNALS
    /* signal system initialization */
    rt_system_signal_init();//信号量初始化，后续分析
#endif

    /* create init_thread */
        /*1.用户应用程序初始化rt_application_init()
            1.1定义一个线程控制块结构体指针变量tid=&main_thread
            1.2创建main线程rt_thread_init()
                1.2.1检查线程指针是否初始化,检查栈开始是否不为0
                1.2.2线程对象初始化rt_object_init()
                    1.2.3.1获取对象信息，属于线程对象information = rt_object_get_information(type);
                    1.2.3.2设置对象类型为静态对象object->type = type | RT_Object_Class_Static;
                    1.2.3.3把main线程控制块main_thread->list插入到对象容器information->object_list中；rt_list_insert_after(&(information->object_list), &(object->list));
                1.2.3线程其他参数初始化_rt_thread_init()
                1.2.3.1初始化线程栈，线程链表
                1.2.3.2初始化线程其他参数
            1.3启动main线程rt_thread_startup()
        ***********************************************/
    rt_application_init();

    /* timer thread initialization */
    rt_system_timer_thread_init();

    /* idle thread initialization */
    rt_thread_idle_init();

    /* start scheduler */
    rt_system_scheduler_start();

    /* never reach here */
    return 0;
}

/* the system main thread */
void main_thread_entry(void *parameter)
{
    extern int main(void);
    extern int $Super$$main(void);

    /* RT-Thread components initialization */
    rt_components_init();

    /* invoke system main function */
#if defined (__CC_ARM)
    $Super$$main(); /* for ARMCC. */
#elif defined(__ICCARM__) || defined(__GNUC__)
    main();
#endif
}

int main(void)
{
    return 0;
}