1.建立中断向量表
b ResetHandler;hereis the first instrument 0x00这是第一条执行的指令
b HandlerUndef ;handler for Undefined mode
b HandlerSWI ;handler for SWI interrupt
b HandlerPabort ;handler for PAbort
b HandlerDabort ;handler for DAbort
b . ;reserved
b HandlerIRQ ;handler for IRQ interrupt
b HandlerFIQ