RT-Thread快速入门-了解内核启动流程

void *rt_memset(void *s, int c, rt_ubase_t count)
void *rt_memcpy(void *dst, const void *src, rt_ubase_t count)
rt_int32_t rt_memcmp(const void *cs, const void *ct, rt_ubase_t count)
char *rt_strstr(const char *s1, const char *s2)
rt_size_t rt_strlen(const char *s)
rt_int32_t rt_snprintf(char *buf, rt_size_t size, const char *fmt, ...)
rt_int32_t rt_sprintf(char *buf, const char *format, ...)

extern int $Super$$main(void);
/* re-define main function */
int $Sub$$main(void)
{
  rtthread_startup();
  return 0;
}

int rtthread_startup(void)
{
  /* 关闭全局中断 */
    rt_hw_interrupt_disable();
    /* 硬件配置初始化 */
    rt_hw_board_init();
    /* 打印 RT-Thread 版本信息 */
    rt_show_version();
    /* 定时器系统初始化 */
    rt_system_timer_init();
    /* 线程调度器初始化 */
    rt_system_scheduler_init();
#ifdef RT_USING_SIGNALS
    /* 信号初始化 */
    rt_system_signal_init();
#endif
    /* 创建用户主线程 main */
    rt_application_init();
    /* 定时器线程初始化 */
    rt_system_timer_thread_init();
    /* 空闲线程初始化 */
    rt_thread_idle_init();
#ifdef RT_USING_SMP
    rt_hw_spin_lock(&_cpus_lock);
#endif /*RT_USING_SMP*/
    /* 启动调度器 */
    rt_system_scheduler_start();
    /* never reach here */
    return 0;
}

/* 系统 main 线程入口函数 */
void main_thread_entry(void *parameter)
{
    extern int main(void);
    extern int $Super$$main(void);
#ifdef RT_USING_COMPONENTS_INIT
    /* RT-Thread 组件初始化 */
    rt_components_init();
#endif    
#ifdef RT_USING_SMP
    rt_hw_secondary_cpu_up();
#endif
    /* 调用系统主函数 main() */
#if defined(__CC_ARM) || defined(__CLANG_ARM)
    $Super$$main(); /* for ARMCC. */
#elif defined(__ICCARM__) || defined(__GNUC__)
    main();
#endif
}

int rt_hw_usart_init(void) /* 串 口 初 始 化 函 数 */
{
  ... ...
  /* 注 册 串 口 1 设 备 */
  rt_hw_serial_register(&serial1, "uart1",
  RT_DEVICE_FLAG_RDWR | RT_DEVICE_FLAG_INT_RX,
  uart);
  return 0;
}
INIT_BOARD_EXPORT(rt_hw_usart_init); /* 使 用 组 件 自 动 初 始 化 机 制 */

void rt_components_board_init(void)
{
  const init_fn_t *fn_ptr;
  for (fn_ptr = &__rt_init_rti_board_start; fn_ptr < &__rt_init_rti_board_end; fn_ptr++)
  {
   (*fn_ptr)();
  }
}

void rt_components_init(void)
{
  const init_fn_t *fn_ptr;
  for (fn_ptr = &__rt_init_rti_board_end; fn_ptr < &__rt_init_rti_end; fn_ptr ++)
  {
    (*fn_ptr)();
  }
}

#define INIT_EXPORT(fn, level) \
            RT_USED const init_fn_t __rt_init_##fn SECTION(".rti_fn." level) = fn
/* board init routines will be called in board_init() function */
#define INIT_BOARD_EXPORT(fn)           INIT_EXPORT(fn, "1")
/* components pre-initialization (pure software initilization) */
#define INIT_PREV_EXPORT(fn)            INIT_EXPORT(fn, "2")
/* device initialization */
#define INIT_DEVICE_EXPORT(fn)          INIT_EXPORT(fn, "3")
/* components initialization (dfs, lwip, ...) */
#define INIT_COMPONENT_EXPORT(fn)       INIT_EXPORT(fn, "4")
/* environment initialization (mount disk, ...) */
#define INIT_ENV_EXPORT(fn)             INIT_EXPORT(fn, "5")
/* appliation initialization (rtgui application etc ...) */
#define INIT_APP_EXPORT(fn)             INIT_EXPORT(fn, "6")
static int rti_start(void)
{
    return 0;
}
INIT_EXPORT(rti_start, "0");
/* 实现 __rt_init_rti_board_start */
static int rti_board_start(void)
{
    return 0;
}
INIT_EXPORT(rti_board_start, "0.end");
/* 实现 __rt_init_rti_board_end */
static int rti_board_end(void)
{
    return 0;
}
INIT_EXPORT(rti_board_end, "1.end");
/* 实现 __rt_init_rti_end */
static int rti_end(void)
{
    return 0;
}
INIT_EXPORT(rti_end, "6.end");

#define SECTION(x)                  __attribute__((section(x)))
/* 该宏的作用是向编译器说明这段代码有用 */
#define RT_USED                     __attribute__((used))