amiga-bootcamp

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Author	SHA1	Message	Date
Ilia Sharin	8133b3a6cb	More content added	2026-04-26 14:46:18 -04:00
Ilia Sharin	aeaea88d75	03/exe_crunchers: expand architecture with full decrunch lifecycle Replaced the brief 'key insight' paragraph with a comprehensive two-phase execution model covering: - Phase 1 (OS): what LoadSeg sees, how wrapper relocations are applied - Phase 2 (stub): all 6 reconstruction steps with code examples: 1. Metadata block preserving original hunk count/sizes/memflags 2. Chip vs Fast RAM allocation (with IMPORTANT warning about DMA-invisible Fast RAM for bitmap/audio data) 3. Decompression into separately allocated hunks 4. Relocation regeneration from embedded tables 5. BPTR segment chain construction (with C code) 6. Wrapper cleanup and JMP to original entry - The segment list handoff problem (double-free hazard) and the three solutions: pr_SegList patching, chain linking, in-place	2026-04-23 18:50:46 -04:00
Ilia Sharin	4593ff135a	03: new article — exe_crunchers.md (executable packers deep dive) New comprehensive article on Amiga executable crunchers covering: - Architecture: how crunched files remain valid HUNK executables - Major crunchers: PowerPacker, Imploder, Shrinkler, ByteKiller, Titanics, CrunchMania, PackFire, XPK framework - PP20 format: efficiency table, decrunch info, decrunch colours - Shrinkler internals: 1536-context adaptive probability model, range coder, parity context flag, stack-based context table, actual 68000 decompressor source from GitHub - LZ77/LZSS vs context-modelling+range-coding algorithms - Relocation handling: 3 strategies (compressed relocs, delta table, merged single-hunk) - Memory layout diagrams: before/during/after decompression - Detection: magic signatures table, fake header warning, Python scanner script - Tools: xfdmaster modular architecture, Ancient C++ library, debugger-based extraction (last resort) - FPGA/emulation impact: timing, self-modifying code, cache Based on web research: verified PP20 format spec, Shrinkler source (askeksa/Shrinkler), Ancient library (temisu/ancient), xfdmaster slave module architecture. Updated indexes: 03/README.md, root README.md	2026-04-23 18:41:07 -04:00

Author

SHA1

Message

Date

Ilia Sharin

8133b3a6cb

More content added

2026-04-26 14:46:18 -04:00

Ilia Sharin

aeaea88d75

03/exe_crunchers: expand architecture with full decrunch lifecycle

Replaced the brief 'key insight' paragraph with a comprehensive
two-phase execution model covering:
- Phase 1 (OS): what LoadSeg sees, how wrapper relocations are applied
- Phase 2 (stub): all 6 reconstruction steps with code examples:
  1. Metadata block preserving original hunk count/sizes/memflags
  2. Chip vs Fast RAM allocation (with IMPORTANT warning about
     DMA-invisible Fast RAM for bitmap/audio data)
  3. Decompression into separately allocated hunks
  4. Relocation regeneration from embedded tables
  5. BPTR segment chain construction (with C code)
  6. Wrapper cleanup and JMP to original entry
- The segment list handoff problem (double-free hazard) and the
  three solutions: pr_SegList patching, chain linking, in-place

2026-04-23 18:50:46 -04:00

Ilia Sharin

4593ff135a

03: new article — exe_crunchers.md (executable packers deep dive)

New comprehensive article on Amiga executable crunchers covering:
- Architecture: how crunched files remain valid HUNK executables
- Major crunchers: PowerPacker, Imploder, Shrinkler, ByteKiller,
  Titanics, CrunchMania, PackFire, XPK framework
- PP20 format: efficiency table, decrunch info, decrunch colours
- Shrinkler internals: 1536-context adaptive probability model,
  range coder, parity context flag, stack-based context table,
  actual 68000 decompressor source from GitHub
- LZ77/LZSS vs context-modelling+range-coding algorithms
- Relocation handling: 3 strategies (compressed relocs, delta
  table, merged single-hunk)
- Memory layout diagrams: before/during/after decompression
- Detection: magic signatures table, fake header warning,
  Python scanner script
- Tools: xfdmaster modular architecture, Ancient C++ library,
  debugger-based extraction (last resort)
- FPGA/emulation impact: timing, self-modifying code, cache

Based on web research: verified PP20 format spec, Shrinkler
source (askeksa/Shrinkler), Ancient library (temisu/ancient),
xfdmaster slave module architecture.

Updated indexes: 03/README.md, root README.md

2026-04-23 18:41:07 -04:00

3 commits