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.

13_toolchain/gcc_amiga.md

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+[← Home](../README.md) · [Toolchain](README.md)
+
+# m68k-amigaos-gcc — Cross-Compiler
+
+## Overview
+
+`m68k-amigaos-gcc` is the GCC-based cross-compiler for AmigaOS, typically based on GCC 2.95 (legacy) or GCC 6.5 (bebbo's fork). It produces Amiga hunk-format executables and supports all 68k variants.
+
+---
+
+## Installation (bebbo's toolchain)
+
+```bash
+# Docker-based (recommended):
+docker pull bebbo/amiga-gcc
+docker run -v $(pwd):/work bebbo/amiga-gcc m68k-amigaos-gcc -o hello hello.c
+
+# Native build (Linux/macOS):
+# NOTE: bebbo removed his repos from GitHub. Use Codeberg or his personal git:
+git clone https://codeberg.org/bebbo/amiga-gcc.git
+# Mirror: https://franke.ms/git/bebbo/amiga-gcc
+cd amiga-gcc
+make update
+make all -j$(nproc)
+# Installs to /opt/amiga/
+```
+
+---
+
+## Usage
+
+```bash
+# Compile and link:
+m68k-amigaos-gcc -noixemul -o hello hello.c
+
+# Common flags:
+#   -noixemul       — use libnix (no ixemul.library dependency)
+#   -m68000          — target 68000 (default)
+#   -m68020          — target 68020+
+#   -m68040          — target 68040
+#   -m68060          — target 68060
+#   -m68881          — use 68881/68882 FPU
+#   -Os              — optimise for size
+#   -O2              — optimise for speed
+#   -fomit-frame-pointer — free up A5
+#   -fbaserel        — base-relative addressing (small data model)
+#   -resident        — generate resident-capable code
+#   -g               — include debug info (HUNK_DEBUG)
+#   -s               — strip symbols
+```
+
+---
+
+## Startup Code
+
+| Startup | Description |
+|---|---|
+| `libnix` | Minimal C runtime, no shared library dependency |
+| `ixemul` | Unix-like C runtime (requires ixemul.library) |
+| `crt0.o` | Raw startup — no C runtime at all |
+
+---
+
+## Inline/Pragma System Calls
+
+```c
+/* Use inline headers to call library functions via registers: */
+#include <inline/exec.h>
+#include <inline/dos.h>
+
+/* Or use proto headers (auto-select inline vs pragma): */
+#include <proto/exec.h>
+#include <proto/dos.h>
+```
+
+---
+
+## References
+
+- Codeberg: https://codeberg.org/bebbo/amiga-gcc
+- Mirror: https://franke.ms/git/bebbo/amiga-gcc
+- GCC 6.5 m68k cross-compiler documentation