# re-bba-rb — on-console test suite (GameCube)

A `.dol` you run from Swiss that drives the adapter in Serial Port 1 and
reports pass/fail per test on the TV.

## Build

Needs devkitPro's `gamecube-dev` group (devkitPPC + libogc). The devcontainer
installs it — if `DEVKITPPC` is unset, **rebuild the container**, since the
toolchain is added in `.devcontainer/Dockerfile`.

```bash
make            # -> gc_bba_test.dol
```

Copy the `.dol` to your SD card (SD Gecko / SD2SP2) and launch it from Swiss.

## Controls

| Button | |
|---|---|
| D-pad up/down | move |
| A | open a suite / rerun the selected test |
| X | run the selected suite |
| START | run everything |
| Y | clear all results |
| B | back |

## What it tests

| Suite | Proves |
|---|---|
| Identity | device enumerates: `04 02 02 00`, HIPR, NWAYS |
| Registers | PAR0–5, IMR writable and read back; IR is write-1-clear |
| Reset/control | NCRA RESET self-clears, SR holds |
| EXI integrity | 200 reads with no bit errors; which EXI clock indices work |
| Ethernet | MAC readback, 60-byte ARP transmit (TI), frame receive (RWP/RI) |
| SPRAM/DMA | ring descriptor is well-formed; reads ≥ 0x100 stream until CS |

## Things that will bite you

**The device ID is a ONE-SHOT.** Address 0 returns `04 02 02 00` only until
the first NCRA reset clears `id_phase` in the gateware; after that it reads
back NCRA. That is correct — it matches the GC's own init order — but it means
the Identity test can only pass once per *console power cycle*. Run it before
the Reset suite. On a re-run the app reports SKIP with an explanation rather
than a misleading failure.

**TI is not proof of transmission.** It only means `TXFrameDrain` handed the
frame to the W5100. A frame can set TI and never reach the wire. The TX test
says so; to confirm the wire, capture on a PC or watch the RX test pick up a
reply.

**The RX test needs traffic.** It waits ~2 s for any frame. On an isolated
link with nothing talking it will fail legitimately — give the PC an address on
the same subnet (the ARP the TX test sends is aimed at `10.0.0.50`, so
`sudo ip addr add 10.0.0.50/24 dev <nic>` makes the PC answer it and both tests
pass together).

**Never over-clock a register read.** Asking for N bytes and clocking more
leaves stale prefetched bytes queued and desynchronises the *next* transaction
— a deterministic every-Nth-read corruption that looks like a signal-integrity
fault. `bba_read()` clocks exactly `len`; don't "round up" for convenience.

**TXDATA takes one byte per transaction.** The register file's effective
address auto-increments per data byte, so a 4-byte write to 0x48 would spill
into 0x49–0x4B. `bba_tx_bytes()` does it correctly.