Re: FPU precision & signal handlers (bug?)

[Alan Cox]

> I agree with the second part, but actually what you want is to start with
> an empty stack. Whether the contents are FP or MMX is irrelevant.
> Actually the support of applications using MMX did not require any change
> to the kernel (Intel carefully designed it that way).

Not the case. If you drop into a signal or exception handler and it uses
FPU while MMX is on it'll get a nasty shock. As it happens Linux already
did the right thing.

Intel minimised it and did pretty much the best job that could be done for
it