From his homepage:
> "I wrote LZEXE in 1989 and 1990 when I was 17."
Incredible.
the reason i posted this isn't because there's a lack of LZEXE unpackers around, but because learning to reverse is hard and i wanted to share an example of the step by step process of what reversing looks like. it's very tedious and slow. functions like these are places where a lot of reversers are going to give up and look elsewhere, so i wanted to show an example of how to break it apart piece by piece instead of getting lost or giving up
Modernizations are especially tricky. Modern compilers can do all sort of weird magic, sometimes combining two or more lines of code into one instruction. Old school compilers don't optimize much which is part of why performance-critical parts of game engines were written in Assembler for a long time.
Not to mention that some stuff you can do in Assembler has no equivalent in higher-level code (e.g. dealing with raw stack frames), and even Assembler to byte code is nowhere near 1:1 reversible.
IDA Pro and Ghidra can identify functions and generate the equivalent C code. I know that this is not the original code, but it does help a bit when you are trying to get an idea of what a large function doing.
