COHERENCE METHOD AND STATE MACHINE EXECUTABLE METHOD FOR MAINTAINING COHERENCE IN A CACHE STORAGE UNIT

摘要

A coherence method in a cache storage unit comprising: transmitting a data portion encoding in reply to a first data request without transmitting a corresponding data request if a corresponding data portion status is one of a set of exclusive clean status encodings; transmitting a second data request according to a presence encoding in response to the first data request if the corresponding data portion status is one of a set of exclusive dirty status encodings; transmitting an invalidation request according to the presence encoding of the corresponding data portion if the first data request is of a first request type and if the data portion status is one of a set of valid status encodings; and setting the data portion status to one of the set of exclusive dirty status encodings if the first data request is of the first request type.