Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!apple!claris!kevin
From: kevin@claris.com (Kevin Watts)
Newsgroups: comp.sys.apple
Subject: Re: Computer languages on the various Apple Corp computers
Message-ID: <10242@claris.com>
Date: 5 Jun 89 17:14:35 GMT
References: <861@ultb.UUCP>
Organization: Claris Corporation, Santa Clara CA
Lines: 25

From article <861@ultb.UUCP>, by lmb7421@ultb.UUCP (L.M. Barstow):
> I believe there is a way around the vast majority of the direct-register
> problem in the Stack relative adressing mode.  I'll admit, you can't
> perform some operations with stack relative (shift operations are the
> big one), and they are a little slower, but I think a register area
> would be most helpful for improved performance, and would be willing to
> assign the direct page to that purpose, using Stack relative for regular
> variables in a stack frame (it was probably the reason for the adressing
> mode anyway).

Hmm, good point.  My initial reponse to this was "but this doesn't work if
I push anything onto the stack during the routine", but then I remembered
that this discussion is mostly about high-level languages, which don't use
the grungy hacks I find myself using in assembly to get decent performance.
All in all, I think this is a very practical way to implement a high-level
language on the 65816.  Performance will be a little slow, but not too bad,
and I still wouldn't want to deal with long data references, but the
picture's better than I thought.  Code space is still going to be a
problem, but no worse than most chips.  Oh well, memory prices are falling
again.

-- 
 Kevin Watts        ! Any opinions expressed here are my own, and are not
 Claris Corporation ! neccessarily shared by anyone else.  Unless they are
 kevin@claris.com   ! patently absurd, in which case they're not mine either.