Redundant LRU Encoding for Cache Directories
Original Publication Date: 1983-May-01
Included in the Prior Art Database: 2005-Feb-07
A technique is described for implementing a least recently used (LR replacement algorithm for two-way set associative caches which provides a number of advantages over the conventional method of using a single directory bit to indicate the usage history of each pair of cache lines. (Image Omitted) cache, a MOD bit is set in the directory, and if that line is subsequently displaced from the cache, it is written back to the main store. Cache initialization following power-up requires that each line also have a validity bit in its directory entry.