[coreboot] About Paging, Realmode and what is going on

Trammell Hudson hudson at trmm.net
Tue Aug 1 18:24:31 CEST 2017


On Tue, Aug 01, 2017 at 02:49:27PM +0000, Peter Stuge wrote:
> Philipp Stanner wrote:
> [...]
> > * Why does every modern CPU still start in RM?
> 
> Many industries run on DOS. Many system developers have created
> in-house BIOS extensions. x86 will never fully lose its 16-bit legacy.

And, just to throw a wrench into things, the Bootguard startup ACM seems
to start in a 32-bit mode of some sort and then shift back to real mode
when it jumps into the legacy reset vector.  I'm not sure what the memory
map looks like during the ACM.

-- 
Trammell



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