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Path: utzoo!watmath!clyde!bonnie!akgua!whuxlm!whuxl!houxm!vax135!petsd!peora!joel
From: joel@peora.UUCP (Joel Upchurch)
Newsgroups: net.arch,net.micro.68k
Subject: Re: M680*0 "small model"
Message-ID: <1069@peora.UUCP>
Date: Sat, 15-Jun-85 15:06:33 EDT
Article-I.D.: peora.1069
Posted: Sat Jun 15 15:06:33 1985
Date-Received: Mon, 17-Jun-85 04:39:14 EDT
References: <167@mot.UUCP>
Organization: Perkin-Elmer SDC, Orlando, Fl.
Lines: 24
Xref: watmath net.arch:1397 net.micro.68k:920

>      The M680*0 small model is not generally supported in M680*0 systems
> and compilers for the following resons:
> 
> 	1. Small models are not as generally applicable as huge models.
> 	2. The M680*0 huge model is also relatively easy to implement.
> 	3. The M680*0 huge model takes a relatively small performance
> 	   'hit' (compared to other common architectures :-)
> 	4. Supporting multiple models requires extra compiler code and 
> 	   redundant libraries.
> 

It sounds to me like what the 68000 needs is an optimizing assembler.
On Perkin-Elmer 3200 series computers there are several addressing
modes, using from 2 to 6 bytes per instruction. The assembler
automatically figures the best addressing mode and generates the
appropiate object code. This is an iterative process, since one
squeeze pass can cause instructions on the next pass to be further
squeezed, since the instruction may be closer to the label it is
referenceing allowing a more compact addressing format to be used.

It seems to me that such a optimizer could be used as a post-processor
for the compiler allowing all languages to use this technique. You
should also have the option of running without squeeze to save compile
time during debug.