[D-runtime] Fibers and x87/SSE control words?

[Sean Kelly]

On Feb 13, 2012, at 10:51 AM, David Nadlinger wrote:

> After a few hours of reverse-engineering x86 SEH, I finally got exceptions in fibers working on my Windows Server 2008 R2 box – sorry, Sean, that I reported them working after your previous changes, I was only testing on my XP VM. Please see: https://github.com/D-Programming-Language/druntime/pull/150 (not super-urgent, but fixes the Thrift async client code)
> 
> Anyway, while working on the code, I noticed that we are currently not saving/restoring the x87 and SSE control words. Now, I'd certainly love to keep the context switching overhead as low as possible, but should we add a pair of stmxcsr/ldmxcsr reps. fnstcw/fldcw for the sake of correctness?

Oops!  I really should have thought of that.  Yes, please prepare a patch.