Branch cache system with instruction boundary determination independent of parcel boundary
US4860197A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 31, 1987 |
| Grant date | Aug 22, 1989 |
| Priority date | — |
| Expiry date | Jul 31, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F9/3816
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A branch cache system for use with a pipelined processor having overlapping parcel prefetch and execution stages. The system includes a plurality of memory sets for storing a plurality of indexed sets of predicted branch addresses, and control circuitry which determines whether there is stored in one of the memory sets a predicted branch address which corresponds to a branch instruction fetched by the prefetch stage. The execution stage is commanded, responsive to detection of a predicted branch address corresponding to that branch instruction, to execute the branch instruction to the predicted branch address. Alternatively, the system includes one or more memory sets for storing predicted branch addresses and corresponding alignment values which represent whether the boundary of a prefetched branch instruction, which is prefetched as one or more parcels, aligns with the fixed boundary of the one or more parcels containing that instruction. The execution stage is commanded to disregard the prefetched parcel containing a portion of the prefetched branch instruction if the alignment value corresponding to the predicted branch address for that prefetched instruction indicates that the…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.