psxrecomp/docs/CONFORMANCE_TESTROM_STATUS.md

External test-ROM conformance status

Date: 2026-08-21

This lane turns small public PS1 hardware tests into deterministic PSXRecomp regression fixtures. It boots the exact pinned PS-X EXE from a locally built disc, captures guest TTY bytes through a bounded debug endpoint, and compares the assertion log with the upstream hardware-derived result.

Current result

Fixture	Assertions	PSXRecomp result	Meaning
gte-test-all	1,150	1,150 passed, 0 failed	All valid GTE opcodes and tested register semantics match the pinned oracle.
cpu-cop	17	Blocked after 2 passes	The strict AOT compiler replaces functions containing intentional invalid COP instructions with psx_unknown_dispatch stubs.

The GTE fixture initially passed zero of its 50 register tests. The oracle then identified and verified title-neutral corrections for register sign extension, RES1, FLAG writes, 44-bit MAC overflow, projection overflow flags, MVMVA edge cases, lighting/color staging, and depth-cue pipeline ordering. The completed fixture passes from a clean prepare -> recompile -> build -> headless run.

The CPU result is not a harness failure. Its first two tests execute and pass; the next intentionally invalid COP instruction reaches generated function 0x80010144, which is a fatal unknown-dispatch stub. A faithful interpreter or exception-generating fallback for compiler-rejected instructions is required before this fixture can test the remaining CPU behavior.

Provenance and boundaries

• Fixture source: JaCzekanski/ps1-tests, MIT, release build-158, commit 5f73d61b27a8d51269b54dde1c456d2d2f7dc865.
• Exact binary/log/archive hashes are in tools/conformance_testrom/fixtures.json and each private run's prepare-receipt.json.
• Fixture binaries and locally owned PlayStation license-sector data are not committed.
• The upstream expected logs are the automated oracle. A matched physical-PS1 recapture remains the promotion gate for a hardware-qualified receipt.

Next factory steps

1. Add a nonfatal compiler fallback for deliberately invalid instructions and finish the 17-test CPU/COP fixture.
2. Have Eagle recapture the hashed synthetic GTE disc on hardware.
3. Add focused CPU, cache, DMA, timer, CD, GPU, SPU, and SIO fixtures one at a time; each must retain exact input hashes and a machine-readable result.
4. Run this lane before whole-game validation so architectural regressions are found below the game layer.

Reproduction instructions are in tools/conformance_testrom/README.md.