amiga-bootcamp/05_reversing

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Reverse Engineering AmigaOS Binaries

Overview

This section provides a systematic methodology for reverse engineering AmigaOS executables and shared libraries using IDA Pro (or Ghidra with the Amiga plugin), with focus on:

• Reconstructing the library JMP table
• Identifying compiler-specific code patterns
• Understanding the exec/dos calling convention at the assembly level
• Tracing library patches (SetFunction)
• Case studies from real Amiga software

Contents

File	Topic
methodology.md	Step-by-step RE workflow for Amiga HUNK binaries
ida_setup.md	IDA Pro configuration for 68k/Amiga analysis
compiler_fingerprints.md	Compiler identification by code patterns
library_reconstruction.md	Reconstructing unknown library JMP tables
patching_techniques.md	Surgical binary patching methods
case_studies/	Real-world RE walkthroughs
case_studies/ramdrive_device.md	ramdrive.device RE walkthrough

Core Principles

1. Know the ABI first — All library calls are JSR LVO(A6). Before reversing any function, identify which library A6 holds using the lib_Node.ln_Name string at base+$00.
2. Use .fd files — The NDK39 .fd files give you every function name and parameter mapping for free.
3. Relocations are your friend — HUNK_RELOC32 entries tell you exactly which longwords are inter-hunk references, making it easy to distinguish code from data.
4. Compiler signatures reduce work — SAS/C vs GCC produces distinct prologues. Identifying the compiler narrows the pattern space dramatically.

Tool Setup

Tool	Purpose
IDA Pro 7.x	Primary disassembler and decompiler (Hex-Rays)
IDA Amiga plugin	HUNK loader, HUNK_SYMBOL import
hunkinfo	Quick hunk/symbol/reloc dump
Ghidra + AmigaOS plugin	Free alternative to IDA
wack / MonAm	On-device debugger

References

• NDK39: fd/, include/
• ADCD 2.1: complete library autodocs
• Amiga ROM Kernel Reference Manual: Libraries and Devices