TNES
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The TNES file format was discovered in Nintendo 3DS Virtual Console games. It fulfills much the same role as iNES format, but it 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 | CHR RAM (0 for none, 1 for 8192 bytes) |
| 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 | |
| 100 | FDS | ROM image consists of 8192 byte BIOS followed by .qd sides, which are 65536-byte FDS sides with CRCs included but no 16-byte header. Size bytes 5-9 are zero, but 10-11 are used. |
References
- Based on TNES format by einstein95, via TCRF forum post
- FDS .qd format
