Method and apparatus for efficiently accessing first and second branch history tables to predict branch instructions
US7278012B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 2, 2005 |
| Grant date | Oct 2, 2007 |
| Priority date | — |
| Expiry date | Jan 10, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F9/3844
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A microprocessor includes two branch history tables, and is configured to use a first one of the branch history tables for predicting branch instructions that are hits in a branch target cache, and to use a second one of the branch history tables for predicting branch instructions that are misses in the branch target cache. As such, the first branch history table is configured to have an access speed matched to that of the branch target cache, so that its prediction information is timely available relative to branch target cache hit detection, which may happen early in the microprocessor's instruction pipeline. The second branch history table thus need only be as fast as is required for providing timely prediction information in association with recognizing branch target cache misses as branch instructions, such as at the instruction decode stage(s) of the instruction pipeline.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.