The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 06, 2011
Filed:
Feb. 15, 2008
Gregory W. Alexander, Pflugerville, TX (US);
Christian Jacobi, Schoenaich, DE;
Barry W. Krumm, Poughkeepsie, NY (US);
Chung-lung Kevin Shum, Wappingers Falls, NY (US);
Aaron Tsai, Poughkeepsie, NY (US);
Gregory W. Alexander, Pflugerville, TX (US);
Christian Jacobi, Schoenaich, DE;
Barry W. Krumm, Poughkeepsie, NY (US);
Chung-Lung Kevin Shum, Wappingers Falls, NY (US);
Aaron Tsai, Poughkeepsie, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method for handling cache coherency includes allocating a tag when a cache line is not exclusive in a data cache for a store operation, and sending the tag and an exclusive fetch for the line to coherency logic. An invalidation request is sent within a minimum amount of time to an I-cache, preferably only if it has fetched to the line and has not been invalidated since, which request includes an address to be invalidated, the tag, and an indicator specifying the line is for a PSC operation. The method further includes comparing the request address against stored addresses of prefetched instructions, and in response to a match, sending a match indicator and the tag to an LSU, within a maximum amount of time. The match indicator is timed, relative to exclusive data return, such that the LSU can discard prefetched instructions following execution of the store operation that stores to a line subject to an exclusive data return, and for which the match is indicated.