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Path: utzoo!linus!philabs!cmcl2!seismo!mcvax!boring!jack
From: jack@boring.UUCP
Newsgroups: net.micro.68k,net.arch
Subject: Re: FLAME!!! Re: EA orthogonality
Message-ID: <6417@boring.UUCP>
Date: Mon, 20-May-85 15:34:07 EDT
Article-I.D.: boring.6417
Posted: Mon May 20 15:34:07 1985
Date-Received: Tue, 21-May-85 05:10:43 EDT
References: <419@oakhill.UUCP> <6415@boring.UUCP> <557@terak.UUCP>
Reply-To: jack@boring.UUCP (Jack Jansen)
Organization: CWI, Amsterdam
Lines: 45
Xref: linus net.micro.68k:730 net.arch:1035
Apparently-To: rnews@mcvax.LOCAL


[ Note that I added net.arch to the newsgroup, since this is probably
where this discussion belongs]

In article <557@terak.UUCP> doug@terak.UUCP (Doug Pardee) writes:
>**** WARNING ****   The following comments are not as nice as etiquette
>recommends.
Agreed. Also, I think they're not true.
> 
>> I think total orthogonality would be *very* useful.
>> ...
>> 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.
>
>What in heck do you think we users are paying you compiler writers to
>DO?
>
>The purpose of a CPU is to solve the *user's* application as quickly as
>possible.
Agreed. In my opinion, this means that the CPU should be optimized to
doing what most users do most of the time: running high-level language
programs.

>
>The purpose of a CPU is *NOT* to be as easy to write a compiler for as
>possible.
Not agreed. If a machine is simple, the compiler is simpler, and thus it
is available sooner, doesn't have as much bugs, etc.
>
>Why on earth should the design of a CPU be based on how easy it will
>make the jobs of the five people who will write the compilers for it?
Because *EVERYONE* will use the product of those five people.
If, for instance, a compiler for a certain machine generates lousy
code for a for-loop, because the compiler writers didn't have time to
optimize it because they were too busy with getting the compiler to *work*
that will waste *HOURS* of CPU time eventually for everyone using it.

This is also the whole point behind RISC architecture, one of the
rising stars at the moment.
-- 
	Jack Jansen, jack@mcvax.UUCP
	The shell is my oyster.