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    SubjectRe: [PATCH] Use correct x86 reboot vector
    Linus Torvalds <> writes:

    > On Sat, 10 May 2003, Jamie Lokier wrote:
    > > Jos Hulzink wrote:
    > > > For the sake of bad behaving BIOSes however, I'd vote for the f000:fff0
    > > > vector, unless someone can hand me a paper that says it is wrong.
    > >
    > > I agree, for the simple reason that it is what the chip does on a
    > > hardware reset signal.
    > Hmm.. Doesnt' a _real_ hardware reset actually use a magic segment that
    > isn't even really true real mode? I have this memory that the reset value
    > for a i386 has CS=0xf000, but the shadow base register actually contains
    > 0xffff0000. In other words, the CPU actually starts up in "unreal" mode,
    > and will fetch the first instruction from physical address 0xfffffff0.
    > At least that was true on an original 386. It's something that could
    > easily have changed since.

    Correct. And no one has changed it since. I use that all of the time.

    > In other words, you're all wrong. Nyaah, nyaah.

    However 0xf000:fff0 is as close as you can get, and since that is usually
    RAM it can do something different on a reset vs a reboot if it wants

    Using 0xf000 is just polite as it allows relative jumps.

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