TNES
The TNES file format was discovered in Nintendo 3DS Virtual Console games. It fulfills much the same role as the iNES format, but it can also encapsulate QD images for FDS games and avoids allegations of having misappropriated a format from the emulation scene.
| Offset | Contents |
|---|---|
| 0-3 | “TNES” ($54 $4E $45 $53) |
| 4 | Mapper (TNES codes, not iNES codes) |
| 5 | PRG ROM size in 8192 byte units |
| 6 | CHR ROM size in 8192 byte units |
| 7 | WRAM (0 for none, 1 for 8192 bytes) |
| 8 | Mirroring (0 mapper-controlled; 1 horizontal; 2 vertical) |
| 9 | Battery (0 none; 1 battery present) |
| 10-11 | Used only for FDS images; purpose unknown, possibly side count |
| 12-15 | Zero |
Mapper numbers differ, and Nintendo’s own ASIC mappers have a contiguous block:
| TNES mapper | iNES mapper | Meaning | Notes |
|---|---|---|---|
| 0 | 0 | NROM | |
| 1 | 1 | SxROM (MMC1) | |
| 2 | 9 | PNROM (MMC2) | |
| 3 | 4 | TxROM (MMC3) | And presumably HKROM (MMC6) |
| 4 | 10 | FxROM (MMC4) | |
| 5 | 5 | ExROM (MMC5) | |
| 6 | 2 | UxROM | |
| 7 | 3 | CNROM | |
| 9 | 7 | AxROM | |
| 31 | 86 | Jaleco JF-13 | |
| 100 | FDS | ROM image consists of a modified 8192 byte BIOS[1] followed by QD sides. Size bytes 5-9 are zero, but 10-11 are used. |
- Based on TNES format by einstein95, via TCRF forum post
- FDS .qd format