Intel architecture ia-32 User Manual
Vol. 3A 9-39
PROCESSOR MANAGEMENT AND INITIALIZATION
Checksum[n]
Data Size +
76 + (n * 12)
76 + (n * 12)
4
Used by utility software to decompose a microcode
update into multiple microcode updates where each of
the new updates is constructed without the optional
Extended Processor Signature Table.
update into multiple microcode updates where each of
the new updates is constructed without the optional
Extended Processor Signature Table.
To calculate the Checksum, substitute the Primary
Processor Signature entry and the Processor Flags
entry with the corresponding Extended Patch entry.
Delete the Extended Processor Signature Table
entries. The Checksum is correct when the summation
of all DWORDs that comprise the created Extended
Processor Patch results in 00000000H.
Processor Signature entry and the Processor Flags
entry with the corresponding Extended Patch entry.
Delete the Extended Processor Signature Table
entries. The Checksum is correct when the summation
of all DWORDs that comprise the created Extended
Processor Patch results in 00000000H.
Table 9-7. Microcode Update Format
31
24
16
8
0
Bytes
Header Version
0
Update Revision
4
Month: 8
Day: 8
Year: 16
8
Processor Signature (CPUID)
12
Res: 4
Exte
nded
F
a
mily
: 8
Exte
nded
Mode: 4
Reserved: 2
T
y
pe: 2
F
a
mily
: 4
Model: 4
S
te
pping
: 4
Checksum
16
Loader Revision
20
Processor Flags
24
Reserved (24 bits)
P7
P6
P5
P4
P3
P2
P1
P0
Data Size
28
Total Size
32
Reserved (12 Bytes)
36
Update Data (Data Size bytes, or 2000 Bytes if Data Size = 00000000H)
48
Extended Signature Count ‘n’
Data Size
+ 48
+ 48
Extended Processor Signature Table Checksum
Data Size
+ 52
+ 52
Reserved (12 Bytes)
Data Size
+ 56
+ 56
Table 9-6. Microcode Update Field Definitions (Contd.)
Field Name
Offset
(bytes)
(bytes)
Length
(bytes)
(bytes)
Description