[SeaBIOS] seabios: About the reset mem address
Amos Kong
akong at redhat.com
Thu Sep 29 05:32:08 CEST 2011
----- Original Message -----
> Amos Kong wrote:
> > [CS base address = CS segment selector * 16]
> > F000H * 16 = F0000H
> > ^^^^^^ (it's not 0xFFFF0000)
> >
> > ==> "CS base address" is not "base address in CS register" ?
>
> Study real mode vs. protected mode. x86 starts in real mode. For
> backwards compatibility, 386 CPUs (the first with full 32-bit
> addressing) and later also start in real mode, but with CS in a
> twilight state, so that the first instruction is actually fetched
> from near top of 4GB, where the boot flash chip is decoded.
Understood.
Thanks for the reply of kevin of peter :)
> > 2. If I only compile seabios, and load the bios.bin to qemu,
> > coreboot will not be used?
>
> Of course not. If you compile Linux, and load bzImage from LILO, will
> gPXE be used? coreboot is one project and SeaBIOS is another. They
> can both be used together and separately.
>
>
> > what's the relationship between coreboot and seabios ?
>
> coreboot picks SeaBIOS as default payload, if the person building
> coreboot does not explicitly provide a payload.
>
> On qemu the initialization done by coreboot is simple, and has been
> included into SeaBIOS instead, probably for convenience, I don't
> know.
>
>
> //Peter
>
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