求高手帮忙看一下，我的代码为什么会被优化掉

unsigned char datatest=0x65;



//unsigned char datarecv;

DatMov g_DatProcess;  //回调函数指针

UINT8        xReadCH376Data( void )  /* 从CH376读数据 */

{



          INT8U ch;

    while(SCI0SR1_RDRF == 0) {           /* Is the transmitter empty? */

    }

    

    ch=SCI0DRL;

    return ch;



}





unsigned char datatest=0x65;



//unsigned char datarecv;

DatMov g_DatProcess;  //回调函数指针



INT8U init_ch376s(DatMov pFunc){



    volatile UINT8 res1=0;

    if(pFunc==NULL){ return;}

    

    g_DatProcess=pFunc;

    

    Init_SCI0(InitBaud);             //376的默认波特率9600

     

     xWriteCH376Cmd( CMD11_CHECK_EXIST );

     xWriteCH376Data(datatest);

     res1=xReadCH376Data();

     LED=0b11111110;

     if (res1 != 0x9A ){return (ERR_USB_UNKNOWN );}

     

      

  /*   xWriteCH376Cmd( CMD21_SET_BAUDRATE );  //设置串口通讯波特率 

   

   #if        UART_WORK_BAUDRATE >= 6000000/256

             xWriteCH376Data( 0x03 );

             xWriteCH376Data( 256 - 6000000/UART_WORK_BAUDRATE );

   #else

      xWriteCH376Data( 0x02 );

            xWriteCH376Data( 256 - 750000/UART_WORK_BAUDRATE );

   #endif

     Init_SCI0(WorkBaud);                   //设置单片机工作波特率与CH376s相同 

     LED=0b11111100;

     res1 = xReadCH376Data( );

     if( res1  != CMD_RET_SUCCESS )  return( ERR_USB_UNKNOWN ); */ // 设置模式错误 

            xWriteCH376Cmd( CMD11_SET_USB_MODE );  //设备USB工作模式 

            xWriteCH376Data( 0x06 );

      res1 = xReadCH376Data( );

      LED=0b11111100;

     if ( res1 != CMD_RET_SUCCESS ) {   return 0x02; }        

                                                             

    

     Drv_INT0Interrupt();              //使能IRQ中断

     Sys_SemCreate(&sem_ch376, 0);  //创建信号量 sem_key          

   

     Sys_CreateTask(TASK_ID_CH376, Ch376Task, 0);

     return (USB_INT_SUCCESS);   

  

 







}

extern res1;

UINT8        xReadCH376Data( void )  /* 从CH376读数据 */

{



          //INT8U ch;

    while(SCI0SR1_RDRF == 0) {           /* Is the transmitter empty? */

    }

    

    res1=SCI0DRL;

    //return ch;



}