From: utzoo!decvax!ucbvax!CAD:tektronix!zehntel!sytek!menlo70!hao!seismo!rocheste!parker
Newsgroups: net.micro.atari
Title: Re: 6502 compilers
Article-I.D.: rocheste.599
Posted: Wed Feb  2 00:13:39 1983
Received: Wed Feb 16 05:38:59 1983

Wow!! Let me start by saying that there are several misleading statements
in your message.  First, you can only do a memory fetch in 5 cycles only
if you have the base address loaded into two page zero locations and the
8-bit index loaded in the Y register.  If you don't have this situation,
you need to take many cycles (instructions) to load these registers.  It
is very hard to write a compiler that makes good use of page zero due to
the fact that you have to share it with the OS and after that there isn't
much of it left for program variables.  Once you start swapping page zero
you lose most of its advantages.  Also, if you have an array with more than
256 bytes, you can't just use the index register anyway.  Enough!!

Now back to the subject of the C compiler sold by OSS.  First of all, it is
NOT a true compiler in that it does not generate 6502 code in the normal
sense.  It really generates subroutine calls which emulate something like a
P-code.  If you look at the BYTE magazine bench mark of Sept. 1981 and the
update of Jan. 1983, you will see that there were several 6502 compilers
tested, the best coming in at 14 seconds (Actually a little bit less than
that if you read the Jan. issue, but its validity is in question since there
weren't any controls), all of the compilers under 20 seconds were for Z80.
The OSS compiler takes about 300 seconds to execute this bench mark and the
Atari PASCAL (compiler) takes about 190 seconds.

Well, now the plug.  There is a compiler for the Atari that generates *real*
6502 machine code.  It comes on an 8K cartridge and includes an Editor (true
full screen) and Monitor as well as the compiler!!!!!  It also generates very
good 6502 code.  It executes the prime number bench mark mentioned above in
13.4, yes I said 13.4, seconds.  It also compiles that bench mark in just 2,
yes I said 2, seconds off the disk!!!  Compare that to the compilation times
of the other compilers in the bench mark (all of them take minutes, not
seconds and are running off of faster disk drives than the Atari).  The 
compile time is only about 1/4 second if you compile it from the editor
buffer!!!

Now that I have you drooling at the mouth (or in total disbelief), let me
tell you that you're going to have to wait to get one.  It isn't scheduled to
come on the market until the end of March (and you won't see any ads for it
until about May).  If things work out, OSS will be carrying this compiler as
well.  It is called AMPL, and if you haven't guessed by now, I'm the author.
If you really can't wait till then, contact me and maybe we can work
something out.

Clinton W. Parker, owner
Action Computer Services
1105 Plymouth Ave. So.
Rochester, NY   14608
(716) 235-6572

rochester!parker