Original-code oracle

The test oracle runs preserved XPK software under headless FS-UAE. It uses Workbench 3.1, XPK master 4.16, Xvfb, and Mesa software rendering. No emulator window is displayed on the host desktop.

For each safe case, the oracle:

1. creates deterministic input;
2. packs and unpacks it with the original Amiga software;
3. decodes the packed container with xfh;
4. compares both outputs byte-for-byte;
5. records modes, exclusions, sizes, and SHA-256 hashes as JSON.

The matrix covers every numeric mode for core codecs and reported mode boundaries for other codecs. Compact representative containers are committed as hexadecimal fixtures in tests/fixtures/oracle; Amiga binaries, ROMs, private files, and full workspaces are not distributed.

Known original-tool failures are explicit exclusions:

• empty input can produce a header rejected by the same XPK master;
• some packer and vector combinations hang;
• ELZX and SLZX hang when their external LZX command is invoked at mode 100;
• SMPL selects raw chunks for all tested inputs;
• CYB1, CYB2, DHUF, and DMCB cannot produce useful compressed fixtures.

The ELZX and SLZX oracle uses the original LZX 1.21R dependency. LHLB uses its original lh.library dependency. Dependency hashes are recorded, but the binaries are not redistributed.

Run the tooling described in tools/fsuae/README.md to create an isolated workspace or verify generated containers.