# Larax & Zaco: an REA-exported evidence base and partial routine recovery

> The author uses REA 6.3.0 with Ghidra to export dossiers, pseudocode and assembly for all 215 discovered procedures in the DOS shareware LEZAC.EXE, then recovers a small set of routines as Pascal and portable C. Recovered code is tested against the original x86 instructions, and a pinned DOSBox-X baseline records original-game runs..

- Type: Case study
- Targets: Binary · Game
- Category: Community REA investigations
- Relationship: Author-reported mixed workflow
- Sources reviewed: 2026-10-18
- Added to the catalog: 2026-11-09
- Original resource: <https://github.com/Hubert-Rybak/lezac-decompilation>
- Primary source: <https://github.com/Hubert-Rybak/lezac-decompilation/blob/73b4bdb3a79cf26346c148d1024c3da5eb3b8333/README.md>
- Catalog page: <https://awesomerea.org/resources/lezac-rea-decompilation-case/>
- Record JSON: <https://awesomerea.org/resources/lezac-rea-decompilation-case/record.json>
- Chinese version: [简体中文](https://awesomerea.org/zh/resources/lezac-rea-decompilation-case/index.md)

## Requirements & limits

- Larax & Zaco v1.0 shareware is the required original input. tools/fetch_original.py downloads a pinned archive or accepts an offline ZIP and verifies file hashes. The original executable and resources are absent from the repository.
- Verification needs Python 3.12+, a C99 compiler, Free Pascal 3.2.2, make, npm and a Node.js version accepted by REA. DOS probes also need the FPC i8086 cross compiler. Re-export needs REA 6.3.0, Ghidra 12.1.4 and a full JDK; original-game runs use DOSBox-X 2024.03.01 and Xvfb.
- Seven Pascal routines, sixteen packed layouts, six portable C routines and resource decoders are recovered. Interrupt handlers, most gameplay, rendering, audio and DOS services remain unrecovered.
- The README reports 174,777 Pascal and 173,725 C comparisons against original x86 code, twelve DOS probe comparisons and 94 loaded-image checks. Gameplay replays use host timing.
- The repository has no license file; RIGHTS.md grants no blanket open-source license for recovered logic or generated pseudocode. The original game and derived exports retain their rights.

## Primary sources

1. <https://github.com/Hubert-Rybak/lezac-decompilation/blob/73b4bdb3a79cf26346c148d1024c3da5eb3b8333/README.md>
2. <https://github.com/Hubert-Rybak/lezac-decompilation/blob/73b4bdb3a79cf26346c148d1024c3da5eb3b8333/RIGHTS.md>
3. <https://github.com/Hubert-Rybak/lezac-decompilation/blob/73b4bdb3a79cf26346c148d1024c3da5eb3b8333/docs/analysis.md>
4. <https://github.com/Hubert-Rybak/lezac-decompilation/blob/73b4bdb3a79cf26346c148d1024c3da5eb3b8333/docs/pascal-recovery.md>
5. <https://github.com/Hubert-Rybak/lezac-decompilation/blob/73b4bdb3a79cf26346c148d1024c3da5eb3b8333/docs/reproduction.md>
6. <https://github.com/Hubert-Rybak/lezac-decompilation/blob/73b4bdb3a79cf26346c148d1024c3da5eb3b8333/docs/emulator-baseline.md>
7. <https://github.com/Hubert-Rybak/lezac-decompilation/blob/73b4bdb3a79cf26346c148d1024c3da5eb3b8333/analysis/provenance.json>
8. <https://github.com/Hubert-Rybak/lezac-decompilation/blob/73b4bdb3a79cf26346c148d1024c3da5eb3b8333/analysis/coverage.json>
9. <https://github.com/Hubert-Rybak/lezac-decompilation/blob/73b4bdb3a79cf26346c148d1024c3da5eb3b8333/analysis/emulator.json>
10. <https://github.com/Hubert-Rybak/lezac-decompilation/blob/73b4bdb3a79cf26346c148d1024c3da5eb3b8333/Makefile>
11. <https://github.com/Hubert-Rybak/lezac-decompilation/blob/73b4bdb3a79cf26346c148d1024c3da5eb3b8333/.github/workflows/verify.yml>

## More in Games

- [Leaflitter: decompiling Paper Mario: Sticker Star for 3DS](https://awesomerea.org/resources/leaflitter-case/index.md) · Case study
- [Legacy of Kain: Soul Reaver — a decompilation and port](https://awesomerea.org/resources/kain2/index.md) · Case study
- [Lego Battles: a hand-decompiled Nintendo DS reconstruction](https://awesomerea.org/resources/lego-battles-decomp-case/index.md) · Case study
- [Lego Island 2: GBA decompilation](https://awesomerea.org/resources/lego-island-2-gba-case/index.md) · Case study
- [LEGO Racers: an N64 source reconstruction in progress](https://awesomerea.org/resources/lego-racers-case/index.md) · Case study
- [LEGO Rock Raiders: a C and C++ decompilation project](https://awesomerea.org/resources/lego-rock-raiders-decompile-case/index.md) · Case study

## About this entry

The description was reviewed against primary sources.
Original editorial content: MIT. Linked projects, papers and assets retain their own rights and licenses.