System to improve trapping of I/O instructions in a peripheral component interconnect bus computer system and method therefor

摘要

A system for trapping I/O instructions. The system is comprised of at least one peripheral controller for receiving a plurality of I/O instructions and for initiating trapping of an un-executable I/O instruction by issuing a target abort signal when the peripheral controller senses a power off condition in a peripheral device. A system controller is coupled to the at least one peripheral controller for receiving the target abort signal from the at least one peripheral controller and for sequentially: issuing a system management interrupt (SMI) signal; counting a predetermined time period to allow recognition of the SMI signal; and issuing a cycle completion signal after counting the predetermined time period. A CPU is coupled to the system controller for issuing a plurality of I/O instructions and for receiving the SMI signal and the cycle completion signal from the system controller.