MICROPROGRAM COMPENSATING CIRCUIT

摘要

PURPOSE:To prevent the subsequent malfunctions by stopping execution of a microprogram of a central processing unit by an interruption signal and at the same time displaying an address preceding by a single access when an access is given to the address of an area storing no microprogram. CONSTITUTION:An interruption control circuit 5 contains plural registers to store plural higher bits, e.g., 3 bits including all addresses storing no microprogram among those addresses to which a central processing unit can give accesses. Then the circuit 5 delivers an interruption signal INT when coincidence is secured among higher 3 bits of an address AD where the unit 1 gives an access to the contents of one of those said registers. The unit 1 stops execution of a microprogram by the signal INT and at the same time displays the address which is preceding by a single access and saved to a stack pointer together with an error code as the error information.