Patent ID: 6065088
Filing Date: 2000-05-16
Classification: G06F

Abstract:
An input/output bus bridge and command queuing system, comprising:an external interrupt router for receiving interrupt commands from bus unit controllers (BUCs) and responding with end of interrupt (EOI), interrupt return (INR) and interrupt reissue (IRR) commands; said interrupt router including a first command queue for ordering EOI commands and a second command queue for ordering INR and IRR commands;a first in first out (FIFO) command queue for ordering bus memory mapped input output (MMIO) commands;means for directing said EOI commands from said first command queue to the input of said FIFO command queue;first means for directing said EOI commands and MMIO commands from said command queue to an input output bus;second means for directing said INR and IRR commands from said second command queue to said input output bus;whereby strict ordering of EOI commands relative to MMIO accesses is maintained while simultaneously allowing INR and IRR commands to bypass enqueued MMIO accesses.