| Version | Code | Data | Functions |
|---|---|---|---|
🇪🇺 Europe (SLES_039.36) |  |  |  |
🇺🇸 USA (SLUS_014.36) |  |  |  |
🇯🇵 Japan (SLPS_034.46) |  |  |  |
   
A work in progress matching decompilation of Digimon World 3 for the PlayStation: C source that compiles back into byte-identical copies of the game's executable, its overlays and its stages. The European release, Digimon World 2003 (SLES_039.36), the most complete one, is the main version: the build's default and the one decomp.dev shows first. The USA release, Digimon World 3 (SLUS_014.36), builds from the same C and matches byte for byte too. The Japanese release, Digimon World 3: Aratanaru Bouken no Tobira (SLPS_034.46), builds from the same C and matches byte for byte as well.
This repository does not contain any game data. You need your own copy of the game to build it.
Each rectangle is a unit, sized by its code; green means it matches. Click it for the details on decomp.dev.
Status
Measured with make report on each version, and written by tools/status_tables.py; the badges above are always current:
| Part | Version | Functions in C | Code | Data |
|---|---|---|---|---|
| Executable, game code | Europe | 346 / 346 | 100.00 % | 100.00 % |
| USA | 346 / 346 | 100.00 % | 100.00 % | |
| Japan | 346 / 346 | 100.00 % | 100.00 % | |
| The 21 overlays | Europe | 1,670 / 1,670 | 100.00 % | 100.00 % |
| USA | 1,665 / 1,665 | 100.00 % | 100.00 % | |
| Japan | 1,670 / 1,670 | 100.00 % | 100.00 % | |
| The stages (293, 238 and 293) | Europe | 1,590 / 1,590 | 100.00 % | 100.00 % |
| USA | 1,369 / 1,369 | 100.00 % | 100.00 % | |
| Japan | 1,590 / 1,590 | 100.00 % | 100.00 % | |
| Total | Europe | 3,606 / 3,606 | 100.00 % | 100.00 % |
| USA | 3,380 / 3,380 | 100.00 % | 100.00 % | |
| Japan | 3,606 / 3,606 | 100.00 % | 100.00 % |
- The game's code and data are all C in the three versions: the executable, the 21 overlays and all the stages.
- The Japanese version builds from the same C too: it is the European version without its languages and PAL video, with the USA disc's file numbers.
- The PsyQ libraries are Sony's code, not the game's: the build takes them from the original as splat's disassembly and the progress leaves them out.
- docs/status.md has the details of each part, how the progress is measured, and the fake matches and hacks the badge counts.
Quick start
Prerequisites
On Debian or Ubuntu (the CI uses Ubuntu 24.04 and Python 3.12), install:
Or build in Docker instead (below).
Clone with the submodules (maspsx, m2c, decomp-permuter and the PsyQ headers), create the Python environment, which must be active whenever you run make or the scripts in tools/, and download the prebuilt tools (GCC 2.8.1 for the PSX, objdiff-cli and mkpsxiso) into bin/, checked against tools/deps.sha256:
Getting the game files
Each disc goes in its own disks/<version>/. Extract it with tools/extract_disc.py, which also reaches the AAA/ directories, and check the executable:
Only disks/<version>/<executable> and disks/<version>/AAA/PRO/ are needed, and only for the versions you build. config/<version>/ holds the SHA-1 of every original binary, which make compare checks the build against: <executable>.sha1, overlays.sha1 and stages.sha1.
Build
The same steps build each version, with VERSION set to eu, us or jp (eu when it is left out):
make compare prints one OK per binary, and a change only counts once every line still says OK: 261 lines for us (the executable, 21 overlays and 239 stages, WSTAG260 among them), 316 for eu and for jp (the executable, 21 overlays and 294 stages):
The CI builds and compares every version on every push.
make VERSION=<version> regenerate deletes asm/<version>/, build/<version>/, expected/<version>/ and assets/<version>/, and splits the binaries again. Run it after changing a config/<version>/*.yaml, a symbol file or stages.txt, so that no stale files stay behind in asm/<version>/.
Building with Docker
tools/docker.sh builds the CI's build environment from the Dockerfile (Ubuntu 24.04, the MIPS binutils, Python and the prebuilt tools, no game data) and runs a command in it, as your own user; without a command it opens a shell. No bin/ or .venv is needed on the host. With the submodules and the disc files in disks/ as above:
docs/toolchain.md has the details.
Checks
The CI runs these on every push; run them before opening a pull request:
docs/shifting.md explains shiftcheck and padcheck, docs/toolchain.md lint, and docs/status.md the report.
Documentation
- The API documentation: the European version's functions, types, globals and macros, with their source and graphs, and these pages (
make docsbuilds it locally). - docs/architecture.md: how the game works as a program (the main loop, the overlays, the tasks, the engine's modules, the field's scripts, the battle) and where each part's code is.
- docs/status.md: the status of each part, how the progress is measured, and the fake matches and hacks.
- docs/binaries.md: the game's executable, overlays and stages, their memory maps, and how the versions are organised.
- docs/toolchain.md: the compiler and its flags, the declaration check, the Docker image, the API documentation (
make docs), the repository's layout and its tools. - docs/shifting.md: the shiftable build and the checks that keep it (
shiftcheck,padcheck,inputcheck). - CONTRIBUTING.md: the matching workflow and the rules on matching, versions, code style, names and pull requests.
Contributing
Read CONTRIBUTING.md before opening a pull request. In short: every function starts as an INCLUDE_ASM line in src/. To decompile one, get a first draft from m2c, make it match with tools/try_match.py, objdiff and, for a near miss, the permuter, then replace the INCLUDE_ASM with it and check that make compare still says OK for every binary of every version.
The PsyQ functions were named from the PsyQ 4.7 signatures.
Links
- decomp.dev: Digimon World 3
- Inspired by these projects: Digimon World decomp, Digimon World 2 decomp, Digimon Digital Card Battle decomp, which links the same PsyQ 4.7 libraries.
- Tools: splat, maspsx, objdiff, m2c, decomp-permuter, old-gcc (the PSX GCC builds), mkpsxiso, psyq_headers.
