Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!henry
From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: net.micro
Subject: Re: Re: 386 Family Products
Message-ID: <6233@utzoo.UUCP>
Date: Mon, 16-Dec-85 19:03:34 EST
Article-I.D.: utzoo.6233
Posted: Mon Dec 16 19:03:34 1985
Date-Received: Mon, 16-Dec-85 19:03:34 EST
References: <129@intelca> <4400130@uiucdcsb> <6185@utzoo.UUCP>
Organization: U of Toronto Zoology
Lines: 24

> > The 80386 still has too few registers, but at least the registers can be
> > pretty much used for whatever the programmer wants, unlike the 80[<3]6.
> 
> oh, don't tell this to Henry Spencer...the 32032 only has 8 general
> purpose registers.  I guess lots of registers just isn't elegant.
> (all this said, tongue implanted firmly in cheek).

It's noteworthy that Bliss-11, at the time the most heavily optimizing
compiler in the known universe, custom-built to exploit the pdp11 to its
limit, and, in particular, making a huge effort to use registers as
effectively as possible, did not manage to use more than 3 or 4 registers
effectively on most programs.  I'm not aware of any more recent work on
this sort of thing (*sigh*, most likely it's sitting in my To Be Read
pile waiting for me to notice it...), but this augurs ill for the usefulness
of large register sets.  Especially since they have to be saved and restored
on function calls and context switches.

Actually, I like lots of registers.  But when I say "lots", I mean LOTS.
As in RISC machine with overlapping windows, with multiple banks so that
I can do process switches without save/restore.  If the register count
doesn't have a "K" on the end, forget it.
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry