System and method for dictionary-based cache-line level code compression for on-chip memories using gradual bit removal

Abstract

A multi-pass compression iteratively removes combinations of bits from locations in each word of a cache line of an uncompressed data stream. For each combination of removed bits, the remaining bits in the word values of the cache line are analyzed to generate a compression score. A highest compression score triggers the building of a dictionary from the remaining bits in the word values of the cache line. After a dictionary is built, the method may continue iteratively to create subsequent dictionaries from the words that remain uncompressed in the cache line. To decompress a word, a first bit section of the compressed word is used to identify a dictionary that is then queried for bits indexed in a second bit section of the compressed word. The uncompressed word is reconstructed by interleaving the queried bits with the removed combination of bits from a third bit section of the word.