Method and apparatus for localized preemption in an otherwise synchronous, non-preemptive computing environment
US5925096A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 8, 1997 |
| Grant date | Jul 20, 1999 |
| Priority date | — |
| Expiry date | Jan 8, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F9/4881
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An apparatus and method for controlling system resource access to a computer application program in an otherwise synchronous, non-preemptive operating environment. A periodic preemption mechanism (PPM) is used to provide periodic CPU access to a client application. Initially, the client application registers a callback address with the PPM. Subsequently, the PPM periodically initiates a preemptive event, upon which the PPM checks for certain critical conditions. If there are no critical conditions, then the PPM saves critical registers of the CPU, then calls the client application at its callback address. In response, the client application performs its function then returns control to the PPM. The PPM then restores the critical registers of the CPU and returns control to the application that was running when the preemptive event occurred. The PPM behaves in a manner in which the operating system is generally unaware of the preemption.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.