Cache memory system with simultaneous read-write in single cycle

A cache includes a number of cache ways each having tag memory fields and corresponding data fields. With a simultaneous read-write operation defined by a read memory address (read tag portion and read index portion) and a write memory address (write tag portion and write index portion), the cache determines a read cache hit and reads from one cache way as indicated by the read tag and index portions of the read memory address. Furthermore, a determination is made as to whether a write as indicated by the write tag and index portions of the write memory address would be made in a same one cache way as the read so as to be in conflict. If such a conflict exists, the write is instead effectuated, simultaneously with the read to the one cache way, to a different cache way than is used for the read.