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.

06_exec_os/exec_base.md

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+[← Home](../README.md) · [Exec Kernel](README.md)
+
+# ExecBase — Full Structure Reference
+
+## Overview
+
+`ExecBase` is the root structure of AmigaOS, located at absolute address `$4`. It is a `struct Library` extended with all exec kernel state: memory lists, task queues, interrupt vectors, library lists, and hardware abstraction fields.
+
+---
+
+## Locating ExecBase
+
+```c
+struct ExecBase *SysBase = *((struct ExecBase **)4);
+```
+
+In assembly:
+```asm
+MOVEA.L  4.W, A6   ; A6 = SysBase
+```
+
+---
+
+## Key Field Groups
+
+### Library Header (offset 0)
+```c
+struct Library  LibNode;     /* +0  — ln_Name = "exec.library" */
+                             /* +20 — lib_Version (40 = OS3.1, 44 = OS3.2) */
+```
+
+### Interrupts (offset +84)
+```c
+UWORD   AttnFlags;       /* +0x128 — processor capability flags */
+UWORD   AttnResched;     /* +0x12A — reschedule attention flag */
+```
+
+### Task Scheduling
+| Offset | Field | Description |
+|---|---|---|
+| +0x128 | `TaskReady` | `struct List` — tasks ready to run |
+| +0x132 | `TaskWait` | `struct List` — tasks waiting on signals |
+| +0x126 | `IDNestCnt` | Interrupt disable nesting count |
+| +0x127 | `TDNestCnt` | Task disable nesting count |
+
+### Memory
+| Offset | Field | Description |
+|---|---|---|
+| +0x130 | `MemList` | `struct List` of `MemHeader` regions |
+| +0x134 | `ResourceList` | Resources list |
+
+### Library and Device Lists
+| Offset | Field | Description |
+|---|---|---|
+| +0x17A | `LibList` | `struct List` — loaded libraries |
+| +0x182 | `DeviceList` | `struct List` — loaded devices |
+| +0x18A | `IntrList` | Interrupt server list |
+| +0x192 | `PortList` | Public message ports |
+| +0x19A | `TaskList` | All tasks (not just ready/waiting) |
+
+### Vectors and ROM
+| Offset | Field | Description |
+|---|---|---|
+| +0x26 | `SoftVer` | Kickstart software revision |
+| +0x10 | `ChkBase` | Checksum of library header |
+| +0x222 | `PowerSupplyFrequency` | 50 or 60 Hz |
+| +0x21E | `ChipRevBits0` | Chip revision detection flags |
+
+### Chip Revision Flags (`ChipRevBits0`)
+
+| Bit | Constant | Chip |
+|---|---|---|
+| 4 | `ATNF_68010` | 68010 or better |
+| 5 | `ATNF_68020` | 68020 or better |
+| 6 | `ATNF_68030` | 68030 |
+| 7 | `ATNF_68040` | 68040 |
+| 10 | `ATNF_FPU40` | 68040 internal FPU |
+
+---
+
+## Detecting CPU and Chipset
+
+```c
+/* CPU: */
+if (SysBase->AttnFlags & AFF_68020) { /* 020+ */ }
+if (SysBase->AttnFlags & AFF_68040) { /* 040 */ }
+
+/* Chipset (via graphics.library): */
+struct GfxBase *gfx = (struct GfxBase *)OpenLibrary("graphics.library", 36);
+if (gfx->ChipRevBits0 & GFXB_AA_ALICE) { /* AGA Alice chip */ }
+```
+
+---
+
+## ExecBase in IDA Pro
+
+After loading Kickstart ROM:
+1. Create a segment at `$4` containing a pointer
+2. Follow the pointer to the ExecBase (in ROM)
+3. Apply `struct ExecBase` type (from NDK39 headers parsed via `File → Parse C header`)
+4. All `N(A6)` offsets auto-annotate as field names
+
+---
+
+## References
+
+- NDK39: `exec/execbase.h` — authoritative field definitions
+- ADCD 2.1: exec.library autodoc
+- *Amiga ROM Kernel Reference Manual: Exec* — ExecBase chapter
+- http://amigadev.elowar.com/read/ADCD_2.1/Libraries_Manual_guide/node0072.html