82801BA Datasheet, PDF (117/498 Pages) Intel Corporation – Intel 82801BA I/O Controller Hub 2 (ICH2) and Intel 82801BAM I/O Controller Hub 2 Mobile

Functional Description
Remote Read Message
Remote read message is used when a local APIC wishes to read the register in another local APIC.
The message format is same as short message for the first 21 cycles.
Table 5-25. Remote Read Message
Cycle
1
2–5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
Bit 1
1
ARBID
NOT(DM)
NOT(M1)
NOT(L)
NOT(V7)
NOT(V5)
NOT(V3)
NOT(V1)
NOT(D7)
NOT(D5)
NOT(D3)
NOT(D1)
NOT(C1)
1
NOT(A)
NOT(A1)
d31
d29
d27
d25
d23
d21
d19
d17
d15
d13
d11
d09
d07
d05
d03
d01
S
C
1
Bit 0
0
1
NOT(M2)
NOT(M0)
NOT(TM)
NOT(V6)
NOT(V4)
NOT(V2)
NOT(V0)
NOT(D6)
NOT(D4)
NOT(D2)
NOT(D0)
NOT(C0)
1
NOT(A)
NOT(A1)
d30
d28
d26
d24
d22
d20
d18
d16
d14
d12
d10
d08
d06
d04
d02
d00
S
C
1
Comments
Normal Arbitration
Arbitration ID
DM = Destination Mode from bit 11 of the redirection table register
M2-M0 = Delivery Mode from bits 10:8 of the redirection table
register
L = Level, TM = Trigger Mode
Interrupt vector bits V7 - V0 from redirection table register
Destination field from bits 63:56 of redirection table register
Checksum for Cycles 6 - 16
Postamble
Status Cycle 0.
Status Cycle 1.
Remote register data 31-0
Data Status: 00 = valid, 11 = invalid
Check Sum for data d31-d00
Idle
NOTE: Cycle 21 through 36 contain the remote register data. The status information in cycle 37 specifies if the
data is good or not. Remote read cycle is always successful (although the data may be valid or invalid)
in that it is never retried. The reason for this is that Remote Read is a debug feature, and a "hung"
remote APIC that is unable to respond should not cause the debugger to hang.
82801BA ICH2 and 82801BAM ICH2-M Datasheet
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