Intel architecture ia-32 사용자 설명서

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Vol. 3A 9-37
PROCESSOR MANAGEMENT AND INITIALIZATION
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Table 9-6.  Microcode Update Field Definitions
Field Name
Offset 
(bytes)
Length 
(bytes)
Description
Header Version
0
4
Version number of the update header.
Update Revision
4
4
Unique version number for the update, the basis for 
the update signature provided by the processor to 
indicate the current update functioning within the 
processor.  Used by the BIOS to authenticate the 
update and verify that the processor loads 
successfully.  The value in this field cannot be used for 
processor stepping identification alone.  This is a 
signed 32-bit number.
Date
8
4
Date of the update creation in binary format: 
mmddyyyy (e.g. 07/18/98 is 07181998H).
Processor 
Signature
12
4
Extended family, extended model, type, family, model
and stepping of processor that requires this particular 
update revision (e.g., 00000650H). Each microcode 
update is designed specifically for a given extended 
family, extended model, type, family, model, and 
stepping of the processor. 
The BIOS uses the processor signature field in 
conjunction with the CPUID instruction to determine 
whether or not an update is appropriate to load on a 
processor. The information encoded within this field 
exactly corresponds to the bit representations returned 
by the CPUID instruction.
Checksum
16
4
Checksum of Update Data and Header. Used to verify 
the integrity of the update header and data. Checksum 
is correct when the summation of all the DWORDs 
(including the extended Processor Signature Table) 
that comprise the microcode update result in 
00000000H.
Loader Revision
20
4
Version number of the loader program needed to 
correctly load this update. The initial version is 
00000001H.
Processor Flags
24
4
Platform type information is encoded in the lower 8 bits 
of this 4-byte field.  Each bit represents a particular 
platform type for a given CPUID.  The BIOS uses the 
processor flags field in conjunction with the platform Id 
bits in MSR (17H) to determine whether or not an 
update is appropriate to load on a processor.  Multiple 
bits may be set representing support for multiple 
platform IDs.
Data Size
28
4
Specifies the size of the encrypted data in bytes, and 
must be a multiple of DWORDs.  If this value is 
00000000H, then the microcode update encrypted 
data is 2000 bytes (or 500 DWORDs).