INTERRUPTION PROCESSOR

PROBLEM TO BE SOLVED: To prevent a processor system from being destroyed by the operation of external circuit by intelligently limiting the flow of interruption information between a microprocessor and an interface chip. SOLUTION: Interruptions received through an Ibus 26 are stored in a register 460 based on their interruption numbers. In case of certain interruption, a value passed together with its interruption number is stored together with the setting instruction of interruption in set or reset state and based on a priority mechanism, the priority is determined. An interruption image register 452 maintains the copy of object to exist in an interruption register 450 at a microprocessor 12. The register 452 is updated by the output of master 466 to an internal bus 490, reserve update contents in the register 452 are compared with contents on the internal bus 490 by a comparator 470 and in order to update the register 450, the quantity of traffic on a Pbus 18 is decreased.