Microprocessor including an interrupt polling unit configured to poll

Abstract

An interrupt polling unit included within a bus interface unit of a microprocessor is provided. The interrupt polling unit causes a periodic interrupt acknowledge bus transaction to occur. If an interrupt controller receiving the interrupt acknowledge bus transaction returns an interrupt vector indicative of an interrupt service routine, then the microprocessor executes the interrupt service routine. The number of interrupt acknowledge bus transactions associated with the interrupt is reduced from two to one, and the microprocessor effectively prefetches the interrupt service routine before the interrupt is actually signaled. In one embodiment, the interrupt polling unit causes an interrupt acknowledge bus transaction to occur at the expiration of a programmable time interval. Another embodiment of the interrupt polling unit causes an interrupt acknowledge bus transaction subsequent to the occurrence of a bus transaction programmed by the user.