Patents by Inventor Steven Butler

Steven Butler has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5353424
    Abstract: A tag comparator and bank selector for a set-associative cache in a computer system operates in a minimum time so that a cache hit or miss signal is generated early in a memory cycle. The data memory of the cache has two (or more) banks, with a tag store for each bank, and the two banks are accessed separately and in parallel using the index (low order address bits) while the tag translation is in progress. Two bit-by-bit tag compares are performed, one for each tag store, producing two multibit match indications, one bit for each tag bit in each tag store. These two match indications are applied to two separate dynamic NOR gates, and the two outputs applied to a logic circuit to detect a hit and generate a bank-select output. There are four possible outcomes from the compare operation: both banks miss, left bank hits, right bank hits, and both banks hit. The later condition indicates a possible ambiguity, and neither data item should be used, so a miss is signalled.
    Type: Grant
    Filed: November 19, 1991
    Date of Patent: October 4, 1994
    Assignee: Digital Equipment Corporation
    Inventors: Hamid Partovi, William R. Wheeler, Michael Leary, Michael A. Case, Steven Butler, Rajesh Khanna