On Mon, 04 Jan 2021 11:05:55 -0500, Dennis Lee Bieber wrote:

> On Mon, 4 Jan 2021 11:00:29 +0000, gareth evans 
> declaimed the following:
>
>>Thinking back to my first job, nearly 50 years ago now,
>>when I had to dis-assemble DEC's paper tape BASIC interpreter in order
>>to enhance it, I guess that dis-assemblers and decompilers must now be
>>ten-a-penny,
>>especially for programs running under Windows where the structure of
>>Windows programs is well-known with an assumption that C was the source
>>language?
>>
>  Actually, I think the use of disassemblers et al has fallen away.
> Modern processors have so many peephole optimizations and out-of-order
> execution streams that converting an executable back to assembly source
> is almost meaningless -- and getting back to a high-level language is
> near impossible. One would have to be an expert at the assembly for a
> processor to have any chance of understanding the result.

The retro-computing guys - those who are fans of the MC6800 and MC6809
microprocessors anyway, anyway, seem to be getting a rather good semi-
interactive disassembler up and running. So far it understands
executables that run under FLEX, FLEX09 for both 6800 and 6809 and under
UniFlex and OS9/level 1 and 2 on a 6809 and can automatically detect
which OS the binary was compiled for. This is quite impressive, since all
four OSen have very different API call structures despite FLEX09,UniFlex
and OS/9 all running on the same chip.


--
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Martin    | martin at
Gregorie  | gregorie dot org

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