11 Facts About Software interrupt

In digital computers, an Software interrupt is a request for the processor to Software interrupt currently executing code, so that the event can be processed in a timely manner.

Consequently, all incoming hardware Software interrupt signals are conditioned by synchronizing them to the processor clock, and acted upon only at instruction execution boundaries.

Each Software interrupt signal is associated with a bit in the mask register.

On some systems, the Software interrupt is enabled when the bit is set, and disabled when the bit is clear.

Spurious Software interrupt is a hardware Software interrupt for which no source can be found.

The result is the processor will think another Software interrupt is pending, since the voltage at its Software interrupt request input will be not high or low enough to establish an unambiguous internal logic 1 or logic 0.

The apparent Software interrupt will have no identifiable source, hence the "spurious" moniker.

Software interrupt is requested by the processor itself upon executing particular instructions or when certain conditions are met.

Level-triggered Software interrupt is requested by holding the Software interrupt signal at its particular active logic level.

The important part of edge triggering is that if the Software interrupt was triggered by a high to low edge transition, that if the level remained low it would not trigger a further Software interrupt.

Shortage of Software interrupt lines is a problem in older system designs where the Software interrupt lines are distinct physical conductors.