[Simh] Fw: Reverse engineering and retrocomputing

[Galen]

I’m curious to hear how many in the simh community have significant interest, or most especially experience, in reverse engineering binary code. Although there’s no reason to limit the discussion to simh-ers, this is the retrocomputing community I know the best, so I thought I’d ask here first.)

Since there is so much historic software to which the sources are no longer available, reverse engineering appears to me to have a lot applicability here.

Perhaps you’ve heard already of Ghidra, the software reverse engineering framework that NSA open-sourced earlier this year?

I do not and have never worked for NSA, but I have some experience of how Ghidra models instruction set architectures. I’ve even used it with a retro architecture myself, the Z80, and managed to help solve some small problems with how Ghidra modeled a few specific instructions. 

I have a real soft spot, though, for the PDP-11, which NSA’s otherwise-wonderful tool doesn’t support. Way back when, in college and the first 10 years or so of my career, I worked a great deal with PDP-11 assembly language as well as knowing enough about the hardware architecture and RSX-11 internals to do some simple drivers and other low-level software.

I’d love an opportunity to help bring support for the PDP-11 to Ghidra but I don’t have time right now to kick off such a project. I could certainly help out significantly, though.

How to model an instruction set architecture in Ghidra isn’t something you can learn from the Ghidra docs, let alone from any other publicly available tutorial material. But Ghidra does include sources for its models of the ISAs that NSA has released support for. Through experience with several of those over the last few years I’ve picked up enough knowledge to help explain some of what you’d find in those models.

What’s the interest here?

Galen
  
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