[coreboot] Code flow from reset vector

Peter Stuge peter at stuge.se
Wed Mar 26 00:40:21 CET 2008

On Tue, Mar 25, 2008 at 12:02:15PM -0700, Viswesh S wrote:
> I understand the coreboot.rom is the BIOS code, which comes inside
> the address mapped in real mode.( 0xA0000 - 0x100000).

Mh, not only.

> If that is the case, then how do we write into the address
> 0xFFFFFFF0, while we flash the BIOS.

386 and up power up with CS set specially so that it "points" at
physical address 0xffff0000. Similar to the flat real mode idea.

A far/long jump changes CS into plain real mode so a far jump is
pretty common early in the boot process.


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