Scoreboard mechanism for serialized string operations utilizing the XER
US6430678B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 29, 1999 |
| Grant date | Aug 6, 2002 |
| Priority date | — |
| Expiry date | Jul 29, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F9/3867
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An XER scoreboard function is provided by utilizing the instruction sequencer unit scoreboard. A scoreboard bit is set if the XER is being used by a previous instruction. If a new instruction is fetched that uses the XER, a dummy read to the XER is generated to test the scoreboard bit to determine if the scoreboard bit is set. If the scoreboard bit is not set when the dummy read is executed, the X-form string proceeds to execution. If the scoreboard bit is set when the dummy is executed, the pipeline is stalled until the scoreboard bit is cleared, and then the X-form string padded with generated padding IOPs (Dummy or NOPs) is executed. After an accessing instruction is executed, the scoreboard bit is cleared.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.