| 摘要 |
<p>PURPOSE:To prevent the destruction of data or the operational defect of programs generated at the time of index modification by tracing data to be set by accessing a data memory using an index register, and verifying the rationality of those data. CONSTITUTION:The program prepared by a program input device 10 is stored through a communication control part 4 into a program memory 1, and upper and lower limit values to the index register are stored in an upper/lower limit value storage part 8 together with an execution address. A program code is read from the memory 1 and transmitted to an instruction detection part 5 by a CPU part 3. When the program code is a write instruction, it is transmitted to a memory control part 6 and a rationality verification part 9 by the instruction detection part 5. The memory control part 6 stores the address, number of times of executing instructions and data value in a trace memory part 7. The rationality verification part 9 reads the execution address and the upper and lower limit values from the upper/lower limit value storage part, collates the transmitted execution address with the data value and reports the result to the CPU part 3.</p> |
