Intel 253668-032US User Manual

Vol. 3 9-39

PROCESSOR MANAGEMENT AND INITIALIZATION

Reserved

Reserved fields for future expansion

Update Data

Data Size or

2000

Update data

Extended Signature

Count

Data Size +

Specifies the number of extended signature structures

(Processor Signature[n], processor flags[n] and

checksum[n]) that exist in this microcode update.

Extended

Checksum

Data Size +

Checksum of update extended processor signature table.

Used to verify the integrity of the extended processor

signature table. Checksum is correct when the

summation of the DWORDs that comprise the extended

processor signature table results in 00000000H.

Reserved

Data Size +

Reserved fields

Processor

Signature[n]

Data Size +

68 + (n * 12)

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.

Processor Flags[n]

Data Size +

72 + (n * 12)

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.

Checksum[n]

Data Size +

76 + (n * 12)

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.

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.

Table 9-6. Microcode Update Field Definitions (Contd.)

Field Name

Offset

(bytes)

Length

(bytes)

Description