Processor architecture having out-of-order execution, speculative branching, and giving priority to instructions which affect a condition code
US5625837A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 6, 1995 |
| Grant date | Apr 29, 1997 |
| Priority date | — |
| Expiry date | Jun 6, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F9/3885
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A processor architecture is described which operates with improved computational efficiency using instruction fetching functions that are decoupled from instruction execution functions by a dynamic register file. The instruction fetching function operates in free-running mode which does not stop if a fetched instruction cannot be executed due to data being unavailable or due to other instruction dependencies. Branch instructions are taken in a predicted direction and the results of execution of all instructions are provisionally stored pending validation or invalidation on the basis of the dependencies becoming available later. For branches of executed instructions that are later invalidated, the results of the executed instructions are flushed from provisional storage and the initial instruction which previously executed at the beginning of a branch on predicted dependencies is re-executed on the actual data that subsequently became available, and all subsequent instructions in such branch are also re-executed on the basis of dependencies actually available from execution of previous instructions in such branch.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.