Note that I still think you should just do the conversion in hardware:
it's slower if done the obvious way, but if you're just a _bit_ clever you
can do the fnsave directly into user space, and thus get the copy for
free, and suddenly the hardware version is not really slower any more, and
is a lot more "obviously right".
> Does the attached patch (against 2.2.5) run your numeric application fine
> now? [There is also a new #define in process.c that switches on the
> 'hardware-based' conversion variants, just in case there are still
> problems.]
I also suspect we _have_ to use fxsave/fxrestore for signal handling.
Think about it. Otherwise the signal execution will destroy the extended
context, and you cannot use the katmai instructions in user space
reliably.
Backwards compatibility is a bitch, though.
Linus
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