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10-56 Vol. 3
ADVANCED PROGRAMMABLE INTERRUPT CONTROLLER (APIC)
1. (IPIs only) It examines the IPI message to determines if it is the specified
destination for the IPI as described in
Section 10.7.2, “Determining IPI Desti-
nation.” If it is the specified destination, it continues its acceptance procedure; if
it is not the destination, it discards the IPI message. When the message specifies
lowest-priority delivery mode, the local APIC will arbitrate with the other
processors that were designated on recipients of the IPI message (see
Section
10.7.2.6, “Lowest Priority Delivery Mode”).
2. If the local APIC determines that it is the designated destination for the interrupt
and if the interrupt request is an NMI, SMI, INIT, ExtINT, or INIT-deassert
Figure 10-25. Interrupt Acceptance Flow Chart for the Local APIC (P6 Family and
Pentium Processors)
Wait to Receive
Bus Message
Belong
to
Destination?
Is it
NMI/SMI/INIT
/ExtINT?
Delivery
Am I
Focus?
Other
Focus?
Is Interrupt Slot
Available?
Is Status a
Retry?
Discard
Message
Accept
Message
Yes
Yes
Accept
Message
Is Interrupt
Slot Avail-
able?
Arbitrate
Yes
Am I Winner?
Accept
Message
Yes
No
Set Status
to Retry
No
No
Yes
Set Status
to Retry
No
Discard
Message
No
Accept
Message
Yes
Lowes
Priority
Fixed
Yes No
No
Yes
No
P6 Family
Processor Specific