10-50 Vol. 3A

ADVANCED PROGRAMMABLE INTERRUPT CONTROLLER (APIC)

Table 10-4.  APIC Bus Status Cycles Interpretation

Delivery

Mode

A Status

A1 Status

A2 Status

Update ArbID 

and Cycle#

Message 

Length

Retry

EOI

00: CS_OK

10: Accept

XX:

Yes, 13

14 Cycle

No

00: CS_OK

11: Retry

XX:

Yes, 13

14 Cycle

Yes

00: CS_OK

0X: Accept Error

XX:

No

14 Cycle

Yes

11: CS_Error

XX:

XX:

No

14 Cycle

Yes

10: Error

XX:

XX:

No

14 Cycle

Yes

01: Error

XX:

XX:

No

14 Cycle

Yes

Fixed

00: CS_OK

10: Accept

XX:

Yes, 20

21 Cycle

No

00: CS_OK

11: Retry

XX:

Yes, 20

21 Cycle

Yes

00: CS_OK

0X: Accept Error

XX:

No

21 Cycle

Yes

11: CS_Error

XX:

XX:

No

21 Cycle

Yes

10: Error

XX:

XX:

No

21 Cycle

Yes

01: Error

XX:

XX:

No

21 Cycle

Yes

NMI, SMI, INIT, 

ExtINT,

Start-Up

00: CS_OK

10: Accept

XX:

Yes, 20

21 Cycle

No

00: CS_OK

11: Retry

XX:

Yes, 20

21 Cycle

Yes

00: CS_OK

0X: Accept Error

XX:

No

21 Cycle

Yes

11: CS_Error

XX:

XX:

No

21 Cycle

Yes

10: Error

XX:

XX:

No

21 Cycle

Yes

01: Error

XX:

XX:

No

21 Cycle

Yes

Lowest

00: CS_OK, NoFocus

11: Do Lowest

10: Accept

Yes, 20

34 Cycle

No

00: CS_OK, NoFocus

11: Do Lowest

11: Error

Yes, 20

34 Cycle

Yes

00: CS_OK, NoFocus

11: Do Lowest

0X: Error

Yes, 20

34 Cycle

Yes

00: CS_OK, NoFocus

10: End and Retry

XX:

Yes, 20

34 Cycle

Yes

00: CS_OK, NoFocus

0X: Error

XX:

No

34 Cycle

Yes

10: CS_OK, Focus

XX:

XX:

Yes, 20

34 Cycle

No

11: CS_Error

XX:

XX:

No

21 Cycle

Yes

01: Error

XX:

XX:

No

21 Cycle

Yes