An array-type computer processor including a data path unit communicating with a state control unit obtains data of a predetermined number of cooperative partial instruction codes, and operates with temporarily holding only a predetermined number of data-obtained instruction codes comprising cooperative partial instruction codes corresponding to contexts and operation states for the data path unit and the state control unit, respectively, from an external program memory which stores data of a computer program. Every time the operations with the temporarily-held instruction codes, including the corresponding cooperative partial instruction codes, are complete, in accordance with event data entered in the state control unit, the subsequent instruction codes are data obtained as cooperative partial instruction codes respectively corresponding to contexts and operating states, so that the operation according to a computer program can be performed even if the data volume of the computer program is over the storage capacity of the data path unit and the state control unit.