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:
Nov. 11, 2003
Filed:
Feb. 18, 2000
Stephen R. Undy, Ft Collins, CO (US);
James E McCormick, Jr., Fort Collins, CO (US);
Hewlett-Packard Development Company, LP., Houston, TX (US);
Abstract
An apparatus and methods for optimizing prefetch performance. Logical ones are shifted into the bits of a shift register from the left for each instruction address prefetched. As instruction addresses are fetched by the processor, logical zeros are shifted into the bit positions of the shift register from the right. Once initiated, prefetching continues until a logical one is stored in the nth-bit of the shift register. Detection of this logical one in the n-th bit causes prefetching to cease until a prefetched instruction address is removed from the prefetched instruction address register and a logical zero is shifted back into the n-th bit of the shift register. Thus, autonomous prefetch agents are prevented from prefetching too far ahead of the current instruction pointer resulting in wasted memory bandwidth and the replacement of useful instruction in the instruction cache.