Partial width stalls within register alias table
US5446912A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 29, 1993 |
| Grant date | Aug 29, 1995 |
| Priority date | — |
| Expiry date | Dec 29, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F9/3858
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A partial width stall mechanism within a register alias table unit (RAT) for handling partial width data dependencies of a given set of operations issued simultaneously within a superscalar microprocessor. Operations of the given set are presented to the RAT in program order and partial width data dependencies occur when the size of a logical source register that is presented to the RAT for renaming to a corresponding physical source register is larger than the corresponding physical source register selected by the RAT. At this occurrence, the data required by the logical source register to be renamed does not reside in any one physical source register. Therefore, renaming of that logical register must be stalled until the data for that logical register is accumulated into one location. The data will be so accumulated when the last operation to have written the physical source register is retired and is, therefore, nonspeculative. The present invention includes a size comparison mechanism to detect the partial width stall condition. Also included is a partial width stall mechanism for preventing the renaming process from operating when the partial width stall condition is detected.…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.