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:
Feb. 17, 2009
Filed:
Jul. 18, 2002
Philip G. Emma, Danbury, CT (US);
Klaus J. Getzlaff, Schonaich, DE;
Allan M. Hartstein, Chappaqua, NY (US);
Thomas Pflueger, Leinfelden, DE;
Thomas R. Puzak, Ridgefield, CT (US);
Eric Mark Schwarz, Gardiner, NY (US);
Vijayalakshmi Srinivasan, New York, NY (US);
Philip G. Emma, Danbury, CT (US);
Klaus J. Getzlaff, Schonaich, DE;
Allan M. Hartstein, Chappaqua, NY (US);
Thomas Pflueger, Leinfelden, DE;
Thomas R. Puzak, Ridgefield, CT (US);
Eric Mark Schwarz, Gardiner, NY (US);
Vijayalakshmi Srinivasan, New York, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A two level branch history table (TLBHT) is substantially improved by providing a mechanism to prefetch entries from the very large second level branch history table (L2 BHT) into the active (very fast) first level branch history table (L1 BHT) before the processor uses them in the branch prediction process and at the same time prefetch cache misses into the instruction cache. The mechanism prefetches entries from the very large L2 BHT into the very fast L1 BHT before the processor uses them in the branch prediction process. A TLBHT is successful because it can prefetch branch entries into the L1 BHT sufficiently ahead of the time the entry is needed. This feature of the TLBHT is also used to prefetch instructions into the cache ahead of their use. In fact, the timeliness of the prefetches produced by the TLBHT can be used to remove most of the cycle time penalty incurred by cache misses.