US Patent 7877587 Branch prediction within a multithreaded processor

Patent 7877587 was granted and assigned to Arm on January, 2011 by the United States Patent and Trademark Office.

Overview Structured Data Issues Contributors Activity

Is a

Patent

Patent attributes

Current Assignee

Arm

Patent Jurisdiction

United States Patent and Trademark Office

Patent Number

7877587

Date of Patent

January 25, 2011

Patent Application Number

11449858

Date Filed

June 9, 2006

Patent Primary Examiner

‌

Eddie P Chan

Patent abstract

A branch prediction mechanism 16, 18 within a multithreaded processor having hardware scheduling logic 6, 8, 10, 12 uses a shared global history table 18 which is indexed by respective branch history registers 20, 22 for each program thread. Different mappings are used between preceding branch behavior and the prediction value stored within respective branch history registers 20, 22. These different mappings may be provided by inverters placed into the shift in paths for the branch history registers 20, 22 or by adders 40, 42 or in some other way. The different mappings help to equalise the probability of use of the particular storage locations within the global history table 18 such that the plurality of program threads are not competing excessively for the same storage locations corresponding to the more commonly occurring patterns of preceding branch behavior.