On Sun, 4 Nov 2007, Linus Torvalds wrote:
>
> So I'd suggest having both jumps back-to-back, but realistically, the
> first regular short jump is actually the one that is more important.
> That's the one that really matters on i386/i486 class machines, and later
> CPU's will generally do the right thing even with _neither_ jump there.
That's obviously badly phrased.
The far jump is obviously required on all CPU's in order for us to
actually finally get to 32-bit protected mode and reload CS, but what I
*meant* was that we certainly also know that "unreal mode" works and is
used by various strange DOS extenders, and that not doing the far jump
isn't really required for having a "working setup" - it's just going to be
a rather limited mode.
So the short jump is required for the code to *work*. The long jump is
required only to get us the 32-bit mode we *want* and out of the odd
"half-way" state. Two different issues.
Linus
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