Re: Why do we still assemble?

hbaker@netcom.com (Henry G. Baker) writes:
> On the original subject of assembling, Dave Mooney tells me that the IBM
> RS/6000 compilers generate object code, and if someone gives the '-S'
> option to get an assembler file, an _additional_ phase is invoked which
> _disassembles_ the '.o' file to get the '.s' file.
>
> What an inspired and elegant solution! Any decent system has to have a
> good disassembler, anyway, so it's better to put good manpower into this
> task than into writing an assembler.


Well... I don't consider this a very elegant solution, myself. First of
all, I lose all the local labels and symbols that the compiler generated
and used but which don't get into the object file. That tends to make the
assembly code much harder to read and use. In fact, there are times when,
although I can get a disassembly of the code from my debugger, I compile
the code with the -S option to get the compiler's assembly code, which is
more readable.


Also, disassembling a relocatable object file is not always the same as
disassembling an executable, so I don't agree that you need that kind of
disassembler anyway. In fact, the only disassemblers we have on our
systems are embedded in other tools -- those disassemblers are not
designed to be "standalone" tools.


> I think that the Burroughs people were pretty proud of the fact that their
> operating system had essentially no assembler code in it. I don't know
> for sure, but I think their (Algol) compiler generated object code
> directly.


Yes, and we can all see how successful that machine was, can't we? :-) :-)
--
Bill Leonard
Harris Computer Systems Division
2101 W. Cypress Creek Road
Fort Lauderdale, FL 33309
bill@ssd.csd.harris.com
[Burroughs systems were without peer in the 1960s, and are still quite common
in the banking industry. Too bad they didn't keep up with IBM's marketing
and hardware development. -John]
--

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