Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!utgpu!water!watnot!watmath!clyde!rutgers!mit-eddie!bacchus!mit-hermes!phr
From: phr@mit-hermes.UUCP
Newsgroups: comp.sys.atari.st
Subject: Re: Porting GCC to Atari ST
Message-ID: <2822@mit-hermes.AI.MIT.EDU>
Date: Fri, 27-Mar-87 01:25:04 EST
Article-I.D.: mit-herm.2822
Posted: Fri Mar 27 01:25:04 1987
Date-Received: Sat, 28-Mar-87 08:26:58 EST
References: <3450@elroy.Jpl.Nasa.Gov> <975@ames.UUCP>
Reply-To: phr@hermes.UUCP (Paul Rubin)
Organization: The MIT AI Lab, Cambridge, MA
Lines: 28
Keywords: C GCC Gnu FSF

In article <975@ames.UUCP> fouts@orville.UUCP (Marty Fouts) writes:
>I am looking into it, but it will be slow going for me.

You might have trouble getting it up on current Ataris.  When GCC
compiles a function, it first builds a syntax tree for the entire
function before it begins to think about it.  This is so it can do
optimizations that need to know everything about the function.
Unfortunately, it means that very large functions can take megabytes
of memory to compile.  In particular, GCC needs about 1.5 meg to
compile its own instruction recognizer (a decision tree pattern
matcher that is several thousand lines of hairy machine-generated C
code).

We may do something in a future release about breaking up large
functions so they can be compiled in a fixed amount of memory.  You
wouldn't get the benefit of certain optimizations on such functions if
this happened.

On a Mega ST with 2 or more meg of memory, compiling the compiler with
itself won't be a problem, of course.

I don't understand the comment that GCC is best used as the code
generator for another compiler.  This makes no sense.  GCC reads in C
programs and produces assembly code.  To run compiled programs, you
need an assembler and linker, and a runtime library.  The GNU versions
of these things probably will not help Atari OS users as the load
formats, etc. are all completely different.  Now when Atari comes
out with a machine that we can run the GNU kernel on...