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

[Martin Nowak]

On Mon, 13 Feb 2012 21:52:13 +0100, Sean Kelly <sean at invisibleduck.org>  
wrote:

> On Feb 13, 2012, at 12:26 PM, Martin Nowak wrote:
>>
>> Calling Fiber.yield is just returning in an unusual manner. As Fibers
>> are not preemptive we shouldn't do that.
>
> I think Fibers can be used in two different ways.  The first is for  
> iteration and such, where the synchronous nature is intended.  The  
> second is within thread pools and such, where the fiber really is a  
> logical thread.  Any ideas for how to resolve the two?

That doesn't really change the matter. When a function returns it should  
reset
it's FPU control word if it was changed. Whether or not it's executed in a  
thread pool
makes no difference. Now if somebody calls Fiber.yield he has to restore  
all callee
cleanup state because he is literally returning to the outer context.