Method and apparatus for predicting memory dependence using store sets
US6108770A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 24, 1998 |
| Grant date | Aug 22, 2000 |
| Priority date | — |
| Expiry date | Jun 24, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F9/3861
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method of scheduling program instructions for execution in a computer processor comprises fetching and holding instructions from an instruction memory and executing the fetched instructions out of program order. When load/store order violations are detected, the effects of the load operation and its dependent instructions are erased and they are re-executed. The load is associated with all stores on whose data the load depends. This collection of stores is called a store set. On a subsequent issuance of the load, its execution is delayed until any store in the load's store set has issued. Two loads may share a store set, and separate store sets are merged when a load from one store set is found to depend on a store from another store set. A preferred embodiment employs two tables. The first is a store set ID table (SSIT) which is indexed by part of, or a hash of, an instruction PC. Entries in the SSIT provide a store set ID which is used to index into the second table, which for each store set, contains a pointer to the last fetched, unexecuted store instruction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.