Implementing a New CPU Architecture for Ghidra [slides]

[guedou]

https://docs.google.com/presentation/d/1b955DV2ii-Dgv6YR4kUrJtjGugEqXD3FffTHRfvVSYo/edit?usp=sharing

[mappu]

This builds upon your previous https://news.ycombinator.com/item?id=17725189 ?

I tried to read more about MeP architecture but there is very little "conventional" info about it

- GCC 3.4 port abandoned http://people.redhat.com/dj/mep/ , what compiler is commonly used?

- Wikipedia page https://en.wikipedia.org/wiki/Media-embedded_processor , well, compare it to RISC-V that contains assembly and microarchitecture details

[guedou → mappu]

Yes,the idea is to use the Ghidra decompiler to ease reversing new parts of the FlashAir firmware.

The MeP-c4 datasheet is available at https://www.datasheetarchive.com/pdf/download.php?id=6693e80...

I had success compiling GCC with MeP support using git and the commit before the removal. Yet, I believe that FlashAir are not compiled with gcc.

[saagarjha]

As far as I'm aware, there's really no way to add support to IDA Pro's decompiler for custom architectures, so I'm really glad that Ghidra has the tools to do this!

[dmitrygr → saagarjha]

That is false. I wrote an IDA plugin to support the VMU CPU. It is actually quite well documented in the IDA SDK. http://dmitry.gr/?r=05.Projects&proj=25.%20VMU%20Hacking

[souprock → dmitrygr]

I don't see any evidence there that you got the decompiler working, which would be quite a feat. The disassembler, and even graph view, is part of the IDA SDK as you mentioned.

[arthurcolle → dmitrygr]

Impressive work! How hard was porting over Flappy Bird over to the VMU? Did you just hand-design the graphics?

[dmitrygr → arthurcolle]

I wrote it in c. Source is on the site :)

[arthurcolle → dmitrygr]

Unfortunately I can't run it locally. Do you have an alternative version for local dev? Ideally for macOS? I'd love to play around with it!

[dmitrygr → arthurcolle]

compile the source for SDL?

or, i also published a VMU emulator (in source) which will build on macos. you can run the cortex-m23 emulator i wrote in it, and then the game in that

[arthurcolle → dmitrygr]

Awesome I'll give that a shot