Final Fantasy Tactics decompilation

About this fork

This is GhostWriter42's fork of adamrt/fft_decomp. The decompilation itself is upstream's work and is unchanged here. This default branch (fork) is upstream's master (as of 2026-10-03, commit 2b09e33) plus this notice and nothing else. The fork's master is kept as a pure mirror of upstream.

What this fork adds, as separate branches that are each based on upstream's master (so each could be proposed upstream on its own). All three keep the build byte-exact: make validate (here fft.ps1 validate) reports all 5,296 functions matching, and fmt-check and check-config pass on top of 2b09e33.

Branch	Commits	What it changes
remove-unneeded-pins-and-barriers	6	Removes 172 compiler-workaround constructs that no longer affect the output: 9 register pins, 2 empty asm barriers, 11 volatile reload casts, 9 volatile pointer views and 141 workarounds in the reconstructed PS1 SDK (132 + 9, in two commits). Found by removing each one and checking the function still matches.
windows-line-endings	2	Adds a .gitattributes that keeps the checkout on LF and a README note on the Windows CRLF pitfall (a CRLF checkout makes check-config fail with "not in canonical form").
document-native-port-ub	2	QUIRKS.md only: undefined behaviour and retail-ABI accidents that a native (non-PS1) build has to neutralise, including a null test after a dereference that modern compilers delete. Items upstream has since documented were dropped.

No pull request has been opened yet. The upstream maintainer has independently fixed several of the same retail-register problems this fork's native-port work ran into; where they did, the fork's version was dropped.

What this is used for: a native build of the game that is checked, frame by frame, against the original machine code (RAM, SDK calls and VRAM), with a GPU renderer, sound and a two-player prototype. All of that lives in a separate repository, GhostWriter42/fft-native-lab (it never edits the decomp; it builds the decomp's C with a few reviewed text patches applied to a generated copy). Its README states, in detail, how it differs from this repository.

The build instructions below are upstream's and work unchanged. Game files are not included, here or in the lab repository; you need your own copy of the game.

Status: 100% decompiled and byte-exact ✅

A matching decompilation of the North American PlayStation release of Final Fantasy Tactics (SCUS-94221 redump). Every game function is C that compiles to the original bytes, and the rebuilt disc is a byte-for-byte match.

Game files and proprietary Sony tools are not included.

Next Steps

The game is 100% completely decompiled, but there are plenty of semantic changes and cleanup to be done. Variable and function names, correcting types, improving enum usage/naming, etc.

Each time a change is made make validate will ensure the changes still match byte-for-byte.

Getting started

Requirements

• Docker
• SCUS-94221 BIN at ./scus-94221.bin (optional)

Then run:

# Prepare environment
make bootstrap

# Then use one of the following (make help for more):
make validate  # verify all code against checksums (without BIN)
make build     # build every module and a byte-matching disc (needs the BIN)

make build writes build/disc/output-scus-94221.bin and .cue.

Thanks

This project is an ode to the FFHacktics community. This project would not be possible without it. ❤️