| 摘要 |
PURPOSE:To check the maintainability of data in an instruction area and to improve reliability by converting an instruction into a dummy NOP instruction by a diagnostic NOP instruction and executing the dummy NOP instruction to execute the memory reading test of an instruction area. CONSTITUTION:The diagnostic NOP instruction and a diagnostic NOP releasing instruction are previously and respectively set up in the leading and final addresses of a program in the instruction area of the memory. When a diagnostic NOP flag 100 is set up by specifying diagnostic NOP setting, all instructions to be decoded by an instruction decoding circuit 70 are processed as NOP instructions. Since the memory reading test of the instruction area of the memory 20 is executed, maintainability of data in the instruction area of the memory 20 can be checked prior to the execution of the program. |
