software interrupt

An interrupt caused by a specific machine language

operation code (e.g. the Motorola 68000's TRAP, the IBMSystem/390's SVC or the ARM's SWI) rather than by a

hardware event.

As with a hardware interrupt, this causes the processor to

store the current state, store identifying information about

the particular interrupt, and pass control to a first level

interrupt handler.

A trap is similar except that it is caused by an unexpected

software condition or error (e.g. divide by zero, undefined

instruction) rather than a deliberate instruction.

(1995-02-14)