At 6:59 PM +0000 2/10/02, Nicholas Clark wrote:
>On Sun, Feb 10, 2002 at 12:08:27PM -0500, Dan Sugalski wrote:
>> The one downside to having continuations is it makes optimizing away
>> variables, even temp ones, a little tough--on switch to any code that
>> might create a continuation we need to flush out from registers to a
>> holding area, and on return from code we need to reload from the
>> holding area. I think we can cope, though. :)
>
>Or maybe we flush out, and have a flag returned (for internal use only) about
>whether this is the first or subsequent time we've returned. And only re-load
>registers on the subsequent times.
>
>But I have this inkling that even if we never use a single continuation, the
>housekeeping involved may be greater than the time saved in reloading
>registers.
Yeah, that's my feeling too. There are a lot of maybes, but the
general case is probably we don't trigger any of them, so it seems
imprudent to twiddle with things.
The one other advantage to a general flush & return scheme with stack
chunk marking is it makes spawning new threads in the same space
potentially faster--we can treat a new thread as a sort of
continuation and when control flow backs up and goes forward we can
fork the stack at that point.
--
Dan
--------------------------------------"it's like this"-------------------
Dan Sugalski even samurai
[EMAIL PROTECTED] have teddy bears and even
teddy bears get drunk
