Re: exception systems

[Matthias Blume <blume@cs.Princeton.EDU>]

From: "Guillermo J. Rozas" <gjr@martigny.ai.mit.edu>
Subject: Re: exception systems
Date: Thu, 18 Apr 96 17:45:49 -0400

> |   Date: Thu, 18 Apr 1996 15:12:31 -0400
> |   From: Matthias Blume <blume@cs.Princeton.EDU>
> 
> |   > In essence I view the bottom-level of interrupt and exception handling
> |   > as a procedure call not visible in the code of the interrupted routine.
> |   > It should require no more overhead than this.
> |
> |   I was actually thinking of *less* overhead than that.  With a
> |   call/cc-based mechanism you get the context switch for free (and
> |   SML/NJ's call/cc mechanism is *very* fast!).  If you use your model,
> |   then you always get the procedure call, and on top of that there will
> |   be the call/cc (as part of the handler's code).
> 
> There is still a procedure call, namely that to the receiver of the
> continuation.

?

> In addition, perhaps VSCM and ML don't do this, but cwcc requires some
> additional context saving on top of whatever overhead the actual
> "stack" requires to preserve:
> 
> - interrupt blocking mask
> - dynamic wind context

Dynamic-wind is another thing that I really like to go and never come
back.

-Matthias