System for signaling serialized interrupts using message signaled interrupts

The present invention provides a system for signaling legacy serialized interrupts within a PCI-Express environment, using message signaled interrupts. The system provides structures and methods that interface a PCI environment with a PCI-Express environment. The present invention provides a PCI to PCI-Express bridge device that is communicatively linked to the PCI and PCI-Express environments. The bridge device comprises a translation function that is communicatively linked to the PCI and PCI-Express environments. A serialized interrupt is signaled from the PCI environment, and the translation function generates a message signaled interrupt within the PCI-Express environment based on that serialized interrupt.