Random comments on LinuxBIOS

Steve Gehlbach steve at nexpath.com
Thu Apr 17 11:56:01 CEST 2003


ron minnich wrote:
> On Wed, 16 Apr 2003, Steve Gehlbach wrote:
> 
> 
>>Given the large LPC flash parts are coming, and so large flash storage, 
>>it seems we should change the startup to set 32-bit mode first, then 
>>jump 32-bit to the start of the assy code.  The usual way that I have 
>>done this jump relative on reset enough bytes below the reset vector, to 
>>setup a flat gdt, and go into 32-bit mode, then jump 32-bit to the flash 
>>code start.  This allows one to start anywhere in flash, not just the 
>>top 64k-bytes. I also think we should default to wp cacheing for the 
>>flash region as well.
> 
> 
> I would rather not. There are chipset reasons for just assuming that only 
> the top 64K of flash is usable, which is why we have left it as is. The
> use of the top 64K is not just due to real mode issues. 
> 

Maybe this is too minor of an issue to take up everyones time on. It 
just seems to me that as the flash parts get larger, limiting ourselves 
to 64K of code space is being trapped in the past.  But we do now have 
compression which helps a lot.

-Steve





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