EEPW论坛

; --- Setup interrupt / exception vectors IF :DEF: ROM_AT_ADDRESS_ZERO ; If the ROM is at address 0 this is just a sequence of branches B Reset_Handler B Undefined_Handler B SWI_Handler B Prefetch_Handler B Abort_Handler NOP ; Reserved vector B IRQ_Handler B FIQ_Handler ELSE 请问：[B]IF :DEF: ROM_AT_ADDRESS_ZERO[/B] 这调语句是怎么理解的阿？