| 摘要 |
PURPOSE:To inhibit the control function, by providing an instruction to deliver key words corresponding to each other at the branch point of a main routine and the input point of the subroutine branched out of the main routine, comparing both key words with each other and deciding the runaway of a program when no coincidence is obtained from the comparison. CONSTITUTION:A CPU main body 1 consisting of a CPU1a, an ROM1b, an RAM1c, a bus 1d and an I/O1e detects a prescribed key word, e.g., Key-1 when a program proceeds and reaches a branch point and then supplies it to a register 3 via a multiplexer 2. At the same time, the main body 1 detects a prescribed key word Kye-1' from the input destination of a program branched out at the branch point and feeds it to a register 4 via the multiplexer 2. The outputs given from both registers 3 and 4 are compared with each other by a comparator 5. Then an error signal is transmitted 13 when no coincidence is obtained from the comparison. As a result, the runaway of a program is detected in an early stage to stop the control function and to prevent the breakdown of the system. |
