Cache memory having enhanced performance and security features

Abstract

A cache memory having enhanced performance and security feature is provided. The cache memory includes a data array storing a plurality of data elements, a tag array storing a plurality of tags corresponding to the plurality of data elements, and an address decoder which permits dynamic memory-to-cache mapping to provide enhanced security of the data elements, as well as enhanced performance. The address decoder receives a context identifier and a plurality of index bits of an address passed to the cache memory, and determines whether a matching value in a line number register exists. The line number registers allow for dynamic memory-to-cache mapping, and their contents can be modified as desired. Methods for accessing and replacing data in a cache memory are also provided, wherein a plurality of index bits and a plurality of tag bits at the cache memory are received. The plurality of index bits are processed to determine whether a matching index exists in the cache memory and the plurality of tag bits are processed to determine whether a matching tag exists in the cache memory, and a data line is retrieved from the cache memory if both a matching tag and a matching index exist in the cache memory. A random line in the cache memory can be replaced with a data line from a main memory, or evicted without replacement, based on the combination of index and tag misses, security contexts and protection bits. User-defined and/or vendor-defined replacement procedures can be utilized to replace data lines in the cache memory.