Global history branch prediction updating responsive to taken branches
US7844806B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 31, 2008 |
| Grant date | Nov 30, 2010 |
| Priority date | — |
| Expiry date | Feb 28, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F9/3848
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A system and method are provided for updating a global history prediction record in a microprocessor system using pipelined instruction processing. The method accepts a microprocessor instruction of consecutive operations, including a conditional branch operation with an associated branch address, at a first stage in a pipelined microprocessor execution process. A global history record (GHR) of conditional branch resolutions and predictions is accessed and hashed with the branch address, creating a first hash result. The first hash result is used to access an indexed branch history table (BHT) of branch direction counts and the BHT is used to make a branch prediction. If the branch prediction being “taken”, the current GHR value is left-shifted and hashed with the branch address, creating a second hash result which is used in creating an updated GHR.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.