> I haven't looked into the exact details, but I guess you're referring to
> the fact that fxsave only saves the "empty" bit.
>
> That's not lossy: the rest of the tag information is implicit in the
> actual value of the stack entry.
>
> It shoul dbe really easy to convert between the new and the old format:
> let the hardware do it for you:
>
> fxrestore new-format
> fnsave old-format
>
> I don't see any loss of information anywhere.. Am I overlooking
> something?
yep this should work. (i optimized this because the above takes about 300
cycles to do, but it's an incorrect approach) But i doubt this is the
cause of the numeric instability observed, nothing i know of relies on the
tag/status word exported through the ptrace interface. [but i agree that
we should be rather correct than fast]
Ingo
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/