Intel 64 and IA-32 Architectures Software Developers Manual Volume 3A, System Programming Guide, Part 1

9-54 Vol. 3A
PROCESSOR MANAGEMENT AND INITIALIZATION
Send Broadcast Message to all processors except self via APIC
Have all processors execute CPUID and record the Processor Signature
(i.e.,Extended Family, Extended Model, Type, Family, Model, Stepping)
Have all processors read IA32_PLATFORM_ID[52:50] and record Platform
Id Bits
If current processor cannot be updated
exit
}
//
// Determine the number of unique update blocks needed for this system
//
NumBlocks = 0
For each processor
{
If ((this is a unique processor stepping) AND
(we have a unique update in the database for this processor))
{
Checksum the update from the database;
If Checksum fails
exit
NumBlocks ← NumBlocks + size of microcode update / 2048
}
}
//
// Do we have enough update slots for all CPUs?
//
If there are more blocks required to support the unique processor steppings
than update blocks provided by the BIOS
exit
//
// Do we need any update blocks at all? If not, we are done
//
If (NumBlocks == 0)
exit
//
// Record updates for processors in NVRAM.
//
For (I=0; I<NumBlocks; I++)
{
//
// Load each Update
//
Issue the WriteUpdate function
If (STORAGE_FULL) returned
{
Display Error -- BIOS is not managing NVRAM appropriately
exit