[lkml]   [2003]   [May]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    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.

    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2005-03-22 13:35    [W:0.024 / U:31.236 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site