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From: guy@sun.uucp (Guy Harris)
Newsgroups: net.lang.c
Subject: Re: more questions about efficient C code
Message-ID: <2391@sun.uucp>
Date: Mon, 8-Jul-85 05:32:42 EDT
Article-I.D.: sun.2391
Posted: Mon Jul  8 05:32:42 1985
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> AT&T compilers these days all come with a tool, call "dis", for
> disassembler. that look at object files and tell you exactly what
> instructions are in them.

Well, some AT&T compilers, anyway - the S5R2 documentation describes DIS(1)
as "3B20 only".

> This is neccessary because it is sometimes not possible to look at a
> .s and tell exactly what instructions the assembler will produce. For
> example an assembler might replace some long forms of jumps by short
> forms.

The PDP-11, VAX, and 68000 assemblers I've seen don't replace long jumps
with short jumps; they replace a "generic" jump with a short or long jump.
Then again, for the purposes of inspecting generated code to see "how good
it is", this shouldn't make much of a difference; looking at the ".s" files
should suffice.  The disassembler may be useful for 3Bs; I believe they have
a "generic" assembler language which translates into 3B20 or WE32000-series
binary code.

	Guy Harris