Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: $Revision: 1.6.2.16 $; site ima.UUCP
Path: utzoo!watmath!clyde!burl!ulysses!allegra!mit-eddie!think!ima!johnl
From: johnl@ima.UUCP
Newsgroups: net.micro.68k
Subject: Re: Re: FLAME!!! Re: EA orthogonality
Message-ID: <75600002@ima.UUCP>
Date: Sun, 26-May-85 23:17:00 EDT
Article-I.D.: ima.75600002
Posted: Sun May 26 23:17:00 1985
Date-Received: Wed, 29-May-85 23:47:47 EDT
References: <5609@utzoo.UUCP>
Lines: 27
Nf-ID: #R:utzoo:-560900:ima:75600002:000:1584
Nf-From: ima!johnl    May 26 23:17:00 1985


While we're all stomping on doug@terak, here's another little reason why
ugly architectures are of concern to other than compiler writers:  You
don't implement a language in a vacuum, and when your'e dealing with a
really ugly chip like tht 80?86 series, the language being compiled often
gets bent so that the compiler writer can finish his job in a finite amount
of time.  Every C compiler ever written for the '86 series has ended up
having several code "models" which do their data and addressing in various
ways that trade off size of usable address space vs. compactness and speed
of object code.  Some compilers have even added "near" and "far" pointer
declarations so that the user can give advice to the compiler about how
to handle dereferencing each pointer.  This means that every compiler user
who wants to compile usefully large programs and still have them run fast
has to learn more than he ever wanted about the strange warts of the '86s
segmented addressing.  I deal with exactly this problem every day (and I
promise, I'm not writing compilers) and it's getting awfully irritating.

Some may find this morally indefensible, but if you put all of the compiler
experts in the world into a room, they still couldn't find a way to generate
decent code for an '86 that appeared to have a linear address space like C
code most naturally wants.

So as has been said before, the 8086 and 286 are fine for high-performance
vending machines, but for real computing, please, give us anything else.
Clever compilers can't paper over this yawning chasm.

John Levine, ima!johnl