Subject: Re: Problems with VIA tech EDEN ESP CPU core.
To: Joern Clausen <joern@TechFak.Uni-Bielefeld.DE>
From: John Clark <>
List: port-i386
Date: 03/28/2005 08:54:30
Joern Clausen wrote:

>On Fri, Mar 25, 2005 at 06:44:51PM -0800, John Clark wrote:
>>I've looked a little bit at the difference between the 1.6.2 boot code 
>>and what is a 'recent' cvs downloaded
>>version of 2.0.
>Have you tried the advice from
>I have not, and I have seen no comments on the list, so maybe you should
>start there.

I'm looking at that. In my brief review of the differences between 1.6 
and 2.0 boot code, there seems to
be some significant differences in the first few lines of the code that 
is in the first boot sector. Since I tuned
out of the x86 world about 15 years ago, I'll have to excavate in my 
brain how Intel things work... but
I'm pretty sure there are some areas that need to be looked at in regard 
to clearing of registers.

In the above mentioned message there is a reference to an andl:

I wonder if just adding:
	andl	$0xffff,%esp
at the start of real_to_prot (in stand/lib/realprot.S)
is what is needed?

Which is suggestive of what could be a problem if the ESP has 'garbage' left over
from the BIOS, ie garbage bits above bit 20. And of course that could be the case
since my BIOS is perhaps different than others, and would suggest why there may
be a variety of symptoms. 

This of course at the moment is all hypothetical.