If used, the start up read only memory (ROM) address range shall be contiguousstarting from physical address 0 up to a maximum of 65,536, as required by the systemapplication. When the start up ROM is enabled, if an I/O or CPU store function isexecuted whose address is within the start up ROM, then the store is attempted intothe main memory. When the start up ROM is enabled, if a read function (instructionor operand) is executed from either I/O or the CPU whose address is to the start upROM, then the read shall be from the start up ROM. When disabled, the start up ROMcannot be accessed.