| 摘要 |
PURPOSE:To prevent program runaway by storing a key corresponding to all modules in advance to a module key register to retrieve a key of the register before an instruction discriminator discriminates an instruction thereby preventing a branch other than a module constituting a program. CONSTITUTION:Full module key information 19 is stored in advance in a full module register 9 of a runaway preventing device from a storage device 1. Further, an instruction 11 in a program read from the device 1 is stored in an execution instruction management device 4, a key 12 of a module belonging to the instruction 11 is stored in a key 5 and compared with the content of the preceding key in a comparison register 6 at a comparator 7. An output signal 13 of the comparator 7 is fed to the device 4 and a retrieval device 10 and when the signal 13 is logical 0, before the device 10 discriminates the instruction 11 of the device 8, whether or not the instruction is registered in the register 9 is retrieved by the content of the register 5 and a coincidence signal 20 is outputted to the device 4. When not registered, an error signal 21 is outputted to prevent runway of the program. |
