I'm currently furthering Ingo's original work on this (it was the basis
for some code that was used in the March 17th PIII Xeon launch event by
Intel). As it turns out, if you really pay attention to detail, it is
*impossible* to reconstruct the complete FPU state that you would
normally get from fsave using only fxsave. The changes to the Tag Word
make it impossible (the fxsave uses a lossy form of saving the tag word
and we can't get that lost information back). So, I have some plans for
getting around that, but right now I'm fighting size problems (as soon
as I do the first fxsave, the machine reboots, presumably because the
task struct has grown too large with the added information or else I'm
missing something somewhere, although it's also possible it could be a
bad gas encoding since I switched to using the actual fxsave and fxrstor
mnemonics while Ingo used hand crafted byte code).
--
Doug Ledford <dledford@redhat.com>
Opinions expressed are my own, but
they should be everybody's.
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