1. A method of controlling a cache memory in a computer system, comprising: determining in which of first and second configurations the cache memory is organized; receiving a memory address; if the cache memory is of the first configuration, then retrieving first tag data stored in the cache memory, and comparing the first tag data to the memory address; and if the cache memory is of the second configuration, then retrieving second tag data stored in the cache memory, and comparing the second tag data to the memory address.