JPS648446A - Information processor - Google Patents

Abstract

PURPOSE:To immediately restart the execution of an instruction without refetching the instruction after the execution of a return instruction and to increase an execution speed by internally saving an instruction code in an instruction queue at the time of executing a call instruction or interrupting operation. CONSTITUTION:An instruction execution part 105 goes to the execution of a call instruction or interrupting operation, an instruction queue initializing line 121 is activated, a gate 30 is opened and the contents 'instruction queue 100 and PC 106-QRDP 109' of a state A are saved to corresponding parts. When the signal line 121 is inactivated, a QWRP 108 and the QRDP 109 are initialized and instruction bytes in an instruction queue 100 are invalidated. When a return instruction is executed, the saved contents are read in the PC 106, a signal line 124 is activated, a comparator 115 is driven, and when the contents of the PC 106 coincide with that of the saved PC 116, a gate 131 is closed and respective saved contents are transferred to corresponding parts. In case of fetching and executing an instruction, approximately similar operation is executed. In said constitution, the execution of an instruction can be restarted immediately after the execution of a return instruction and the performance of a computer can be improved.