A memory circuit including memory elements on which data read, write and store operations can be arbitrarily performed, the memory elements having a dyadic/arithmetic operation function. In a read/modify/write mode to be executed during a memory cycle and in an interval in which data from the memory elements and data from external devices exist, an operation is executed between external data and the data in the memory elements and the result of such operation is stored during a write cycle, thereby achieving a higher-speed operation.