Method and apparatus for predicting, clearing and redirecting unpredicted changes in instruction flow in a microprocessor
US5729728A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 6, 1996 |
| Grant date | Mar 17, 1998 |
| Priority date | — |
| Expiry date | Sep 6, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F9/3844
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A simplified method and apparatus for handling the change of instruction control flow in a microprocessor is provided. Rather than attempting to implement a change in the instruction flow immediately, the processor first recognizes that flow is to be redirected from a predicted instruction flow to a correct instruction flow according to a flow control indicator. The flow control indicator may be attached to instructions flowing down the pipeline or inserted as a separate instruction in the pipeline. The pipeline is cleared of state created by instructions that do not follow the correct instruction flow, i.e., instructions that were erroneously fetched after the instruction causing the change in flow. The change in flow as indicated by the flow control indicator is implemented later in the pipeline.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.