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amiga-bootcamp/04_linking_and_libraries/README.md
Ilia Sharin 21751c0025 docs(amiga): complete AmigaOS 3.1/3.2 developer reference — 172 files across 17 sections 
Comprehensive technical documentation covering:
- Hardware: OCS/ECS/AGA custom chip registers, Copper & Blitter deep dives
- Boot sequence: cold boot through startup-sequence
- Binary format: HUNK executable spec, relocation, debug info
- Linking & ABI: .fd files, LVO tables, register calling conventions
- Exec kernel: tasks, interrupts, memory, signals, semaphores
- AmigaDOS: file I/O, FFS/OFS layout, CLI/Shell scripting
- Graphics: planar bitmaps, Copper programming, HAM/EHB modes
- Intuition: screens, windows, IDCMP, BOOPSI
- Devices: trackdisk, SCSI, serial, timer, audio, keyboard
- Libraries: utility, expansion, IFFParse, locale, ARexx
- Networking: bsdsocket API, SANA-II, TCP/IP stack comparison
- Toolchain: GCC, vasm/vlink, SAS/C, NDK, debugging
- Reverse engineering: IDA/Ghidra setup, compiler fingerprints, case studies
- CPU & MMU: 68040/060 emulation libs, PMMU, cache management
- Driver development: SANA-II, Picasso96/RTG, AHI audio

All files include breadcrumb navigation. No local paths or proprietary content.
2026-04-23 12:17:35 -04:00

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Linking & Library Integration

Overview

This section documents how AmigaOS shared libraries work at the binary level — how compilers produce library call stubs, how the linker wires them up, and how to reconstruct this mechanism during reverse engineering.

Contents

File Topic
library_structure.md Library node, LVO table, OpenLibrary mechanics
fd_files.md Function Definition files — the library ABI source
lvo_table.md JMP table layout and reconstruction
compiler_stubs.md How SAS/C, GCC, VBCC call libraries
setfunction.md Runtime function patching with SetFunction
startup_code.md c.o / gcrt0.S — startup and exit sequences

The Library ABI Model

Every AmigaOS shared library exposes its functions through a negative-offset JMP table relative to the library base pointer:

Library base:  LIB+0    → Library node (struct Library)
               LIB-6    → JMP _funcN   (last function)
               LIB-12   → JMP _funcN-1
               ...
               LIB-6    → JMP _func1   (first user function)

A C call like OpenLibrary("graphics.library", 0) compiles to:

MOVE.L  4.W, A6          ; A6 = SysBase (exec)
JSR     -552(A6)          ; LVO for OpenLibrary = -552

The negative offset (-552) is the Library Vector Offset (LVO) — a fixed ABI value defined in the library's .fd file and proto/ include.

References