Method for compacting an instruction queue
US6704856B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 17, 1999 |
| Grant date | Mar 9, 2004 |
| Priority date | — |
| Expiry date | Dec 17, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F9/384
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method of compacting an instruction queue in an out of order processor includes determining the number of invalid instructions below and including each row in the queue, by counting invalid bits or validity indicators associated with rows below and up to the current row. For each row, multiplexor select signals are generated from the flat vector counts for the N rows above and including the present row, and from the validity indicators associated with the N rows, where N is a predetermined value. A multiplexor associated with a particular row selects one of the N rows according to the select value, and moves or passes the instruction held in the selected row to the present row. A row's select value is determined by forming a diagonal from the N count vectors corresponding to the N rows above and including the present row, and logically ANDing, each diagonal bit with the valid bit associated with the same row. Each row's count vector is determined in two stages. In the first stage, a local count is determined for each row in a local group of rows, and a global count is determined for the entire local group. Each local count is determined by counting the validity indicators associa…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.