Global branch prediction using branch and fetch group history
US9921846B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 8, 2013 |
| Grant date | Mar 20, 2018 |
| Priority date | — |
| Expiry date | Jul 7, 2035 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F9/3861
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
This disclosure includes a method for performing branch prediction by a processor having an instruction pipeline. The processor speculatively updates a global history register having fetch group history and branch history, fetches a fetch group of instructions, and assigns a global history vector to the instructions. The processor predicts any branches in the fetch group using the global history vector and a predictor, and evaluates whether the fetch group contains a predicted taken branch. If the fetch group contains a predicted taken branch, the processor flushes subsequently fetched instructions in the pipeline following the predicted taken branch, repairs the global history register to the global history vector, and updates the global history register based on branch prediction information. If the fetch group does not contain a predicted taken branch, the processor updates the global history register with a branch history value for each branch in the fetch group.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.