Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Show HN: Decomp Academy – Learn to decompile GameCube games into matching C

decomp-academy.dev

Post reply on HN
Print view View original

41–50 of 83 posts

Re: Show HN: Decomp Academy – Learn to decompile GameCube games into matching C

#41

Post by low_tech_love »

jonhohle wrote: post #14
OsrsNeedsf2P wrote: post #13

Dumb question about reverse engineering binaries: is there a way to only do it piecemeal? I'm eventually waiting for LLMs and harnesses to get good enough to reverse engineer BFME (old Lord of the Rings game that still has an active modding community), but it's a multi GB sized game that would have to be done in bite-sized pieces. Basically; can you reverse engineer in bite sized pieces, and recompile/customize their…

Most decomp projects (that I know of) are Ship of Theseus style projects where the minimum unit is a function, give or take alignment requirements and quirks of the compiler. On the MIPS side, tools like Splat and SPIM can help identify function and even source file boundaries, generate inline ASM C files[0], and write linker scripts to build a matching binary. You can then go through and replace the ASM functions on…

Interesting when you mention Ship of Theseus, I never thought of that but I wonder if that is where the name “Ship of Harkinian” comes from?

Re: Show HN: Decomp Academy – Learn to decompile GameCube games into matching C

#42

Post by realusername »

oneshtein wrote: post #33

Dumb question — can LLM be used to reverse-engineer firmware blobs or binary only drivers for Linux, to create open-source drivers, for example, for unsupported smartphones?

As I'm working in this area, I can say that the biggest problem isn't binary only drivers but spotty mainline support of core features (provided that we're talking about Android phones, not iPhones or old Windows mobile stuff)

Re: Show HN: Decomp Academy – Learn to decompile GameCube games into matching C

#43

Post by dataflow »

> If even 1 instruction or bit is off, that's a fail.

Does this assume having access to the exact version of the compiler use, or can it be done with a different compiler in practice?

And do you care about things like binary layout, or just instruction match? (Does that ever matter in practice?)

Re: Show HN: Decomp Academy – Learn to decompile GameCube games into matching C

#44

Post by RossBencina »

realusername wrote: post #42
oneshtein wrote: post #33

Dumb question — can LLM be used to reverse-engineer firmware blobs or binary only drivers for Linux, to create open-source drivers, for example, for unsupported smartphones?

As I'm working in this area, I can say that the biggest problem isn't binary only drivers but spotty mainline support of core features (provided that we're talking about Android phones, not iPhones or old Windows mobile stuff)

From where you're standing, what does the path to improving mainline support of core features look like? Aside from sheer volume of work are there other major challenges or opportunities? In the past I've hacked around adding stuff to Armbian kernels, but navigating a path to mainline seemed like a whole other job.

Re: Show HN: Decomp Academy – Learn to decompile GameCube games into matching C

#45

Post by HiPhish »

Love the idea! Assembly has been on my forever-list to eventually learn. I have worked through the warmup exercises, but I doubt I'll have the time to continue much past that. A few points of note:

- Not a fan of the purple theme, it screams "AI-generated". It's not a deal breaker, you can keep it if you have more important concerns, but just something to point out

- It would be nice to have a "Chapter 0" for a primer on assembly syntax. Does not have to be interactive, a few toy examples I can work out on paper would be good enough

- Maybe I just haven't seen it, but it would be nice to have a reference of all the various instructions. Your lessens explain them well enough, but I would like to have a list of all of them at a glance so I can look up instructions from earlier chapters later.

Re: Show HN: Decomp Academy – Learn to decompile GameCube games into matching C

#46

Post by realusername »

RossBencina wrote: post #44
realusername wrote: post #42

Earlier quoted context omitted.

As I'm working in this area, I can say that the biggest problem isn't binary only drivers but spotty mainline support of core features (provided that we're talking about Android phones, not iPhones or old Windows mobile stuff)

From where you're standing, what does the path to improving mainline support of core features look like? Aside from sheer volume of work are there other major challenges or opportunities? In the past I've hacked around adding stuff to Armbian kernels, but navigating a path to mainline seemed like a whole other job.

It really depends of your device but some SOC have very poor mainline support and are essentially living in a forked repo with nothing sent to lkml, others have partial support in mainline but with some of the core features being broken.

Drivers can also be partially implemented / buggy depending on the device. (And I'm not talking about closed source stuff, even things like usb or touch screen drivers).

I would say that the major blocker is that nobody really cares about these devices and the task itself to mainline them is gigantic.

Most SOC have 3 or maybe 4 contributors maximum and the phonedev kernel mailing list gets a new patch only every 2 days. The whole phone mainlining community is probably less than 60 people.

Re: Show HN: Decomp Academy – Learn to decompile GameCube games into matching C

#48

Post by allan_s »

HiPhish wrote: post #45

Love the idea! Assembly has been on my forever-list to eventually learn. I have worked through the warmup exercises, but I doubt I'll have the time to continue much past that. A few points of note: - Not a fan of the purple theme, it screams "AI-generated". It's not a deal breaker, you can keep it if you have more important concerns, but just something to point out - It would be nice to have a "Chapter 0" for a prime…

Is "the layout scream AI generated" the new Bootstrap ? I.e what people use to quickly convey their ideas (bad or good)

Ironically, for myself at least, the least it looks AI, the more I've spent time prompting for it to not look AI.

Re: Show HN: Decomp Academy – Learn to decompile GameCube games into matching C

#50

Post by StilesCrisis »

koala_man wrote: post #34
jackpriceburns wrote: post #8

Earlier quoted context omitted.

AI is being used in many retro game decomp projects! One of the reasons I went down the path of learning decomp myself was because AI had hit a wall. Matching decomp is quite a bit harder than just normal decomp as even simple things like using an if/else instead of a terney actually change the assembly. AI did an amazing job of getting to 95% matches on nearly all functions, but once it got to that tail end, it star…

Matching decomp would require the same compiler and flags as the original game, right? How is that determined?

Experimentally, I think. There's only a few dozen options, and you can winnow it down to just a few pretty quickly.
Post reply on HN