Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.1 6/24/83 (MC840302); site boring.UUCP
Path: utzoo!linus!philabs!cmcl2!seismo!mcvax!boring!jack
From: jack@boring.UUCP
Newsgroups: net.micro.68k
Subject: Re: More on PC relative destinations and a new one on EA orthogonality
Message-ID: <6415@boring.UUCP>
Date: Wed, 15-May-85 12:55:22 EDT
Article-I.D.: boring.6415
Posted: Wed May 15 12:55:22 1985
Date-Received: Thu, 16-May-85 22:01:36 EDT
References: <419@oakhill.UUCP>
Reply-To: jack@boring.UUCP (Jack Jansen)
Organization: CWI, Amsterdam
Lines: 36
Apparently-To: rnews@mcvax.LOCAL


In article <419@oakhill.UUCP> davet@oakhill.UUCP (Dave Trissel) writes:
>
>B) We have tossed about some ideas for including total orthogonality for most
>   of the instructions.  Assuming that its workable, we have another problem
>   in that looking at over 7,000 instructions generated by
>   Pascal and C compilers on the NS32032 we have found very little use
>   of any memory to memory operations not already available on the M68000
>   family. In fact, the National code (with half the registers of the M68000)
>   only uses them about 2 percent of the time. This discourages us from even
>   considering such an addition.
>
I think total orthogonality would be *very* useful. The fact that the
32K is totally orthogonal turned me from a Motoroladdict to a
Nationalist (sad for you, but true).
As a small example (much better ones can be found, no doubt), 
consider the definition
	extern int i;
	register int j;
and the statements
	if( i < j ) foo;
	if( j < i ) bar;

A 68K compiler has to think about modifying the branch condition, etc.
A 32K compiler just generates code in the way it sees the statement.

Of course, an optimizer might throw everything around again
to save registers or whatever, but the inital code generation is
much simpler in the 32K case.

By the way, if you are going to include total orthogonality,
how do you want to do it? I can't imagine any feasible way aside
from totally changing object code format (oh nooooooo)...

-- 
	Jack Jansen, jack@mcvax.UUCP
	The shell is my oyster.