> I've thought about it, but (given my hardware situation, mostly; i'm
> stuck having only alphas... 8-)

My sympathies :-)

> I'd definitely like to see such numbers, for a couple of different
> processors, before this was jumped into.

Something Charles said made me think this is already being
done (at least in the x86 port)?  Any way, this is probably
not much of a saving for fat context switches (like in
Unix).  On the other hand, _eager_ FP saving is an
inefficiency that can be removed with a modest amount of
coding and every little bit adds up (even easy coding may
seem like a waste of time for a paltry 1% improvement but do
this 10 times and ...).  Also, such a change follows the
`don't pay for what you don't use' principle.

--bakul