Predicting instruction branches with a plurality of global predictors using varying amounts of history instruction
US7243219B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 24, 2003 |
| Grant date | Jul 10, 2007 |
| Priority date | — |
| Expiry date | Jan 8, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F9/3848
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Systems and methods of processing branch instructions provide for a bimodal predictor and a plurality of global predictors. The bimodal predictor is coupled to a prediction selector, where the bimodal predictor generates a bimodal prediction for branch instructions. The plurality of global predictors is coupled to the prediction selector, where each global predictor generates a corresponding global prediction for a branch instruction using different history or stew lengths. The prediction selector selects branch predictions from the bimodal prediction and the global predictions in order to arbitrate between predictors. The arbitration, update, and allocation schemes are designed to choose the most accurate predictor for each branch. Lower level predictors are used as filters to increase effective predictor capacity. Allocate and update schemes minimize aliasing between predictors. Branch predictors incorporating a plurality of global predictors in this fashion are more adaptive than conventional predictors with fixed branch history lengths and are able to achieve superior accuracy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.