INFORMATION PROCESSING UNIT

PURPOSE:To execute the switching of a record without fetching an activation record to a register file by providing an activation record group, which respectively belongs to plural tasks, to a register bank on the register file in an instruction processing unit. CONSTITUTION:When a certain task is in an executing condition and a procedure is called, an activation record 3 is newly generated and allocated to a register file 1. Then, a register bank pointer 5 is operated and linked to the head of the linked list of the activation record 3, which belongs to the task. Then, at such a time point, the execution of a program is controlled. When a certain task is in the executing condition and return from the procedure, which is just executed, to a procedure, which calls the above mentioned procedure, is generated, the activation record 3 to control the execution of the procedure of the task up to such a moment is released and a register bank pointer 6 is held to the former activation record.