[SeaBIOS] seabios 0.6.1 regression

Kevin O'Connor kevin at koconnor.net
Tue Nov 16 01:18:59 CET 2010


On Mon, Nov 15, 2010 at 06:09:45PM +0200, Avi Kivity wrote:
> On 11/15/2010 05:49 PM, Avi Kivity wrote:
> >On 11/15/2010 05:41 PM, Avi Kivity wrote:
> >>
> >>I think it's a miscompile.
> >>
> >>out/code16.o:
> >> 1a4:   3e                      ds
> >> 1a5:   6c                      insb   (%dx),%es:(%edi)
> >>
> >>Note no 66 prefix.
> >>
> >
> >It isn't, that was random crap.  All the insb() code is 32-bit.
> >
> 
> Rewriting it to use inb / stos works (jecxz ; insb; loop doesn't) so
> it looks like a kernel bug in insb emulation.

Ughh.  I can revert that change on stable-0.6.1 if needed.  It sounds
like we really do want this on the main branch though for the speed
benefit it provides.

-Kevin



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