mirror of
https://github.com/alfishe/amiga-bootcamp.git
synced 2026-06-13 00:26:28 +00:00
52 lines
2.4 KiB
Markdown
52 lines
2.4 KiB
Markdown
|
[← Home](../README.md)
|
||
|
|
|
||
|
|
# Executable Loader & HUNK Format
|
||
|
|
|
||
|
|
## Overview
|
||
|
|
|
||
|
|
This section covers the complete lifecycle of an AmigaOS executable:
|
||
|
|
|
||
|
|
1. **HUNK file format** — the binary container for all AmigaOS executables, libraries, and object files
|
||
|
|
2. **Loader pipeline** — how `dos.library` loads and relocates an executable into memory
|
||
|
|
3. **Object files** — how compilers produce relocatable object files for the linker
|
||
|
|
4. **Overlays** — how programs larger than available memory use the overlay system
|
||
|
|
|
||
|
|
## Contents
|
||
|
|
|
||
|
|
| File | Topic |
|
||
|
|
|---|---|
|
||
|
|
| [hunk_format.md](hunk_format.md) | Complete HUNK binary specification |
|
||
|
|
| [hunk_ext_deep_dive.md](hunk_ext_deep_dive.md) | HUNK_EXT: exports, imports, commons |
|
||
|
|
| [hunk_relocation.md](hunk_relocation.md) | HUNK_RELOC32/16/8 mechanics |
|
||
|
|
| [hunk_debug_info.md](hunk_debug_info.md) | HUNK_SYMBOL, HUNK_DEBUG (stabs) |
|
||
|
|
| [exe_load_pipeline.md](exe_load_pipeline.md) | LoadSeg → Process creation |
|
||
|
|
| [object_file_format.md](object_file_format.md) | Compiler object files (HUNK_UNIT) |
|
||
|
|
| [overlay_system.md](overlay_system.md) | HUNK_OVERLAY memory segmentation |
|
||
|
|
|
||
|
|
## Why HUNK?
|
||
|
|
|
||
|
|
HUNK is the native AmigaOS executable format, used from AmigaOS 1.0 through 3.x. It predates ELF/COFF and has these key properties:
|
||
|
|
|
||
|
|
- **Segmented**: separate code, data, and BSS hunks with independent memory allocation
|
||
|
|
- **Relocatable**: all absolute references are patched at load time (no ASLR; base address changes each run)
|
||
|
|
- **Typed memory**: each hunk can request `CHIP` or `FAST` memory independently
|
||
|
|
- **Symbol-complete**: optional HUNK_SYMBOL and HUNK_DEBUG hunks carry debugging information
|
||
|
|
|
||
|
|
## Key Concepts
|
||
|
|
|
||
|
|
| Term | Meaning |
|
||
|
|
|---|---|
|
||
|
|
| **Hunk** | One contiguous block in the binary (code, data, BSS, etc.) |
|
||
|
|
| **Segment** | A loaded hunk at runtime — a `BPTR`-linked list |
|
||
|
|
| **Segment list** | Chain of loaded hunks returned by `LoadSeg()` |
|
||
|
|
| **BPTR** | Amiga byte pointer — 32-bit value right-shifted by 2 (`ptr >> 2`) |
|
||
|
|
| **Relocation** | Patching absolute addresses based on actual load address |
|
||
|
|
| **LVO** | Library Vector Offset — negative offset from library base |
|
||
|
|
|
||
|
|
## References
|
||
|
|
|
||
|
|
- ADCD 2.1: `Includes_and_Autodocs_3._guide/` — dos.library LoadSeg autodoc
|
||
|
|
- NDK39: `dos/dos.h` — BPTR, segment handling macros
|
||
|
|
- *Amiga ROM Kernel Reference Manual: Libraries* — AmigaDOS chapter
|
||
|
|
- http://amigadev.elowar.com/read/ADCD_2.1/Libraries_Manual_guide/node0150.html
|