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.

01_hardware/aga_a1200_a4000/README.md

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+[← Home](../../README.md) · [Hardware](../README.md)
+
+# AGA Chipset — A1200 / A4000 / CD32
+
+## Overview
+
+The **Advanced Graphics Architecture** (AGA) is the final custom chipset developed by Commodore, shipping from 1992. It dramatically expands colour depth, palette size, sprite capabilities, and blitter bandwidth while retaining full OCS/ECS backward compatibility.
+
+## Chip Summary
+
+| Chip | Name | Changes from ECS |
+|---|---|---|
+| **Alice** | MOS 8374 | Super Agnus successor: 64-bit bus, FMODE register |
+| **Lisa** | (unnamed MOS) | ECS Denise successor: 8-bit palette, 256 colours |
+| **Paula** | MOS 8364 | Unchanged from OCS/ECS |
+
+## Contents
+
+| File | Topic |
+|---|---|
+| [chipset_aga.md](chipset_aga.md) | Alice and Lisa internals, AGA architecture |
+| [aga_registers_delta.md](aga_registers_delta.md) | New/changed registers vs ECS |
+| [aga_palette.md](aga_palette.md) | 24-bit colour system, 256 registers |
+| [aga_display_modes.md](aga_display_modes.md) | HAM8, 256-colour, doublescan, VGA |
+| [aga_blitter.md](aga_blitter.md) | 64-bit blitter bus, FMODE |
+| [cpu_030_040.md](cpu_030_040.md) | 68030/040 on A3000/A4000: cache, MMU, FPU |
+| [gayle_ide_a1200.md](gayle_ide_a1200.md) | A1200 Gayle: IDE and PCMCIA specifics |
+
+## AGA vs ECS — Key Differences
+
+| Feature | ECS | AGA |
+|---|---|---|
+| Colour registers | 32 (12-bit) | **256 (24-bit)** |
+| Max simultaneous colours | 64 EHB / HAM | **256** (or HAM8: 262,144) |
+| Blitter bus | 16-bit | **64-bit** (FMODE) |
+| Sprite width | 16 px | **64 px** |
+| Sprite colours | 3+transparent | **15+transparent** (64-colour attached) |
+| Bitplane depth | 6 planes max | **8 planes** |
+| Palette select | 1 bank | **4 bitplane banks, 4 sprite banks** |
+
+## Identifying AGA at Runtime
+
+```c
+#include <graphics/gfxbase.h>
+
+extern struct GfxBase *GfxBase;
+
+BOOL is_aga = (GfxBase->ChipRevBits0 & (1 << GFXB_AA_ALICE)) != 0;
+```
+
+| ChipRevBits0 bit | Flag | Meaning |
+|---|---|---|
+| 4 | `GFXB_AA_ALICE` | AGA Alice present |
+| 5 | `GFXB_AA_LISA` | AGA Lisa present |
+
+## AGA Machines
+
+| Model | CPU | Notes |
+|---|---|---|
+| A1200 | 68020 14 MHz | Budget AGA; Gayle IDE; PCMCIA; 2 MB Chip |
+| A4000 | 68030/040 25 MHz | High-end; Zorro III; IDE; 2 MB Chip + Fast |
+| A4000T | 68040/060 | Tower variant; SCSI |
+| CD32 | 68020 14 MHz | Game console; CD-ROM; SX-1 expansion |
+
+## References
+
+- ADCD 2.1 Hardware Manual — AGA chapters
+- NDK39: `graphics/gfxbase.h`, `hardware/custom.h`
+- Commodore A1200/A4000 Technical Reference Manuals (local archive)