Re: [patch-2.3.46-p2] P6 microcode update support

[Tigran Aivazian]

Rui Sousa wrote:
> Just out of curiosity, how much can you change with the microcode, in terms
> of processor "behavior"? And what processors support it?
> And what about the microcode, is there any information on how to "build your
> own"
> or are you limited to the ones prepackaged by intel?
> 
> Any URL where I can read more about it would do fine... It's not like I intend
> to do anything with it but, it's the first time I hear about this feature and
> I would like to know more.

dropped Linus and Peter from cc as they surely know more about this
stuff than I anyway :)

Basically, no you can't roll your own microcode because nobody knows how
it works. The microcode encoding format is documented but the actual
data bits are just that - bits...

The good reading is section 8.10 of Volume III of Pentium III manual
available for free download from:

         http://developer.intel.com/design/pentiumii/manuals/243192.htm

I would suggest to read the first volume and then the third using the
second as an instruction reference (which is what it is).

Regards,
Tigran.