typedef void (*function_ptr)(void);
int main(int argc, char **argv)
{
    rt_thread_t thread;
    uint8_t index = 0;
    uint8_t *buf;
    rt_base_t level = rt_hw_interrupt_disable(); //关闭rt中断
    buf=rt_malloc(1024*1024);
    read_flash(1, 0x100000, IAPP, 0xf0000);
    unsigned char *ram_data = (unsigned char *)RAM_ADDRESS;
    for(int i=0;i<0xf0000;i++)
    {
        ram_data[i]=IAPP[i];
    }
    rt_free(buf);
    function_ptr func = (function_ptr)RAM_ADDRESS;
    sysSetGlobalInterrupt(1);//关闭全局中断
    func();  // 调用RAM中的函数

    main stack overflow