Method and apparatus for performing read accesses from a counter which avoid large rollover error when multiple read access cycles are used
US5566322A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 19, 1993 |
| Grant date | Oct 15, 1996 |
| Priority date | — |
| Expiry date | Nov 19, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F9/321
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Method and apparatus for performing read accesses from a counter (40) while avoiding the large rollover error that may occur when the counter (40) is read using more than one read access cycle. In one embodiment, the present invention monitors the most significant bit of the lower portion (44) of counter (40) for a transition indicating that a rollover has taken place. If a rollover has not occurred, read accesses take place in the normal manner. However, if a rollover has occurred during the latency period between a read access from the upper portion (42) of counter (40) and a corresponding read access from the lower portion (44) of counter (40), the read access from the lower portion (44) is inhibited and a default value is placed on the bus (36) instead.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.