[Mono-list] Re: Is Objective-C support possible?

Fergus Henderson fjh@cs.mu.oz.au
Tue, 19 Feb 2002 21:22:37 +1100

On 19-Feb-2002, Fergus Henderson <fjh@cs.mu.OZ.AU> wrote:
> On 17-Feb-2002, Carl R. Witty <cwitty@newtonlabs.com> wrote:
> > Pinku Surana <surana@rover.cs.nwu.edu> writes:
> > 
> > >      * box/unbox should use tagged pointers in some cases,
> > >        particularly integers. With tailcalls, this improves
> > >        performance of continuations.
> > 
> > This has the problem (as pointed out in the referenced article) that
> > you get integers which are less than 32 bits long.  I'm sure this
> > isn't allowed by the .NET specification.
> The CLR specification requires that the `int32' type hold 32 bits.
> But there's nothing to stop an implementation from extending the CLR
> by adding e.g. an `int28' type.

Or alternatively, the optimization of using tagged pointers could be done
only for those integers which happened to fit; integers which require
the full 32 bits could be boxed in the usual manner.  This would probably
catch >95% of cases...

Fergus Henderson <fjh@cs.mu.oz.au>  |  "I have always known that the pursuit
The University of Melbourne         |  of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh>  |     -- the last words of T. S. Garp.