Patrik Rak's Z80 instruction exerciser: exhaustive per-instruction CRCs compared against captures from a real Zilog Z80 in a 48K Spectrum. Vendored release taps (pkg/testharness/testdata/z80test) run on the 48K harness via direct CODE-block injection. All six CPU variants pass; z80ccfscr is manual/visual only. Upstream: https://github.com/raxoft/z80test.
| Test | Status | Notes |
|---|---|---|
| z80doc | pass | All registers, documented flags — 160/160 pass |
| z80docflags | pass | Documented flags only — 160/160 pass |
| z80flags | pass | All flags — 160/160 pass (Q register + block/OUTx flag work, ZX Play #141) |
| z80full | pass | All flags and registers — 160/160 pass |
| z80ccf | pass | Flags after CCF following every instruction — 160/160 pass (the Q register) |
| z80memptr | pass | BIT n,(HL) after every instruction — 160/160 pass (MEMPTR emulation is deeper than its in-source caveat suggests) |
| z80ccfscr | manual | Visualises random CCF behaviour; emulators produce a stable pattern by construction — manual/visual only, not wired into CI |