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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.
51 lines
2.4 KiB
Markdown
51 lines
2.4 KiB
Markdown
[← Home](../README.md)
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# Executable Loader & HUNK Format
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## Overview
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This section covers the complete lifecycle of an AmigaOS executable:
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1. **HUNK file format** — the binary container for all AmigaOS executables, libraries, and object files
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2. **Loader pipeline** — how `dos.library` loads and relocates an executable into memory
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3. **Object files** — how compilers produce relocatable object files for the linker
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4. **Overlays** — how programs larger than available memory use the overlay system
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## Contents
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| File | Topic |
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|---|---|
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| [hunk_format.md](hunk_format.md) | Complete HUNK binary specification |
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| [hunk_ext_deep_dive.md](hunk_ext_deep_dive.md) | HUNK_EXT: exports, imports, commons |
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| [hunk_relocation.md](hunk_relocation.md) | HUNK_RELOC32/16/8 mechanics |
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| [hunk_debug_info.md](hunk_debug_info.md) | HUNK_SYMBOL, HUNK_DEBUG (stabs) |
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| [exe_load_pipeline.md](exe_load_pipeline.md) | LoadSeg → Process creation |
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| [object_file_format.md](object_file_format.md) | Compiler object files (HUNK_UNIT) |
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| [overlay_system.md](overlay_system.md) | HUNK_OVERLAY memory segmentation |
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## Why HUNK?
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HUNK is the native AmigaOS executable format, used from AmigaOS 1.0 through 3.x. It predates ELF/COFF and has these key properties:
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- **Segmented**: separate code, data, and BSS hunks with independent memory allocation
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- **Relocatable**: all absolute references are patched at load time (no ASLR; base address changes each run)
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- **Typed memory**: each hunk can request `CHIP` or `FAST` memory independently
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- **Symbol-complete**: optional HUNK_SYMBOL and HUNK_DEBUG hunks carry debugging information
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## Key Concepts
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| Term | Meaning |
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|---|---|
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| **Hunk** | One contiguous block in the binary (code, data, BSS, etc.) |
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| **Segment** | A loaded hunk at runtime — a `BPTR`-linked list |
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| **Segment list** | Chain of loaded hunks returned by `LoadSeg()` |
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| **BPTR** | Amiga byte pointer — 32-bit value right-shifted by 2 (`ptr >> 2`) |
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| **Relocation** | Patching absolute addresses based on actual load address |
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| **LVO** | Library Vector Offset — negative offset from library base |
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## References
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- ADCD 2.1: `Includes_and_Autodocs_3._guide/` — dos.library LoadSeg autodoc
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- NDK39: `dos/dos.h` — BPTR, segment handling macros
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- *Amiga ROM Kernel Reference Manual: Libraries* — AmigaDOS chapter
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- http://amigadev.elowar.com/read/ADCD_2.1/Libraries_Manual_guide/node0150.html
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