Apic Controller - GE VR11 Reference Manual

APIC Controller

GE Intelligent Platforms – VR11, VP11 Hardware Reference Manual, Second Edition
The VR11 supports APIC (Advanced Programmable Interrupt Controller). This
handling of the APIC interrupt services must be supported by the operating
system. The I/O APIC handles interrupts very differently than the 8259.
Briefly, these differences are:
•
Method of Interrupt Transmission. The I/O APIC transmits interrupts
through processor FSB, and interrupts are handled without the need for the
processor to run an interrupt acknowledge cycle.
•
Interrupt Priority. The priority of interrupts in the I/O APIC is independent
of the interrupt number. For example, interrupt 10 may be given a higher
priority than interrupt 3.
•
More Interrupts. The three I/O APICs in the VR11 support a total of 28
independent interrupt sources.
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