Non-stalling pipeline tag controller

Abstract

A non-stalling pipeline tag controller includes cascaded source and holding registers coupled respectively to an external input unit and a data memory module. A tag memory module includes a tag memory unit for storing tags to memory data in the data memory module, and a first comparator unit that generates a first decision signal to indicate whether the source tag in the source register matches with one of the tags in the tag memory unit. A status module includes a second comparator unit that generates a second decision signal to indicate whether the source tags stored in the source and holding registers match with one another, and a decision unit that compares the first and second decision signals and that generates a third decision signal to indicate occurrence of a cache hit or cache miss condition. An arbitration module generates a control signal for enabling access to the data memory module according to the source tag from the holding register upon detection of the cache hit condition, and generates a replacement address that is provided to the tag memory module so as to enable storage of the source tag from the holding register in the tag memory unit according to the replacement address in order to update the tag memory unit upon detection of the cache miss condition.