| 1 | FCE Ultra General User's FAQ |
| 2 | preliminary version |
| 3 | ------------------ |
| 4 | |
| 5 | |
| 6 | Q: Why doesn't the NSF <insert name here> work(correctly) on FCE Ultra? |
| 7 | A: Some NSF rips are bad. Some read from addresses that are not specified |
| 8 | in the NSF specifications, expecting certain values to be returned. |
| 9 | Others execute undocumented instructions that have no affect on |
| 10 | less-accurate software NSF players, but will cause problems on NSF players |
| 11 | that emulate these instructions. Also, the playback rate specified |
| 12 | in the NSF header is currently ignored, though I haven't encountered |
| 13 | any problems in doing this. |
| 14 | |
| 15 | |
| 16 | Q: Why doesn't the game <insert name here> work(correctly) on FCE Ultra? |
| 17 | A: Many factors can make a game not work on FCE Ultra: |
| 18 | |
| 19 | - If the ROM image is in the iNES format(typically files that have |
| 20 | the extension "nes"), its header may be incorrect. This |
| 21 | incorrectness may also be because of garbage in the |
| 22 | header. Certain utilities used to put text in the reserved |
| 23 | bytes of the iNES header, then those reserved bytes were |
| 24 | later assigned functions. FCE Ultra recognizes and |
| 25 | automatically removes(from the ROM image in RAM, not on the |
| 26 | storage medium) SOME header junk. |
| 27 | |
| 28 | If the game has graphical errors while scrolling, chances are |
| 29 | the mirroring is set incorrectly in the header. |
| 30 | |
| 31 | You can try to edit the header with a utility(in the NES |
| 32 | utilities section at http://zophar.net ) or a hex editor. |
| 33 | |
| 34 | - The on-cart hardware the game uses may not be emulated |
| 35 | correctly. |
| 36 | |
| 37 | - Limitations of the ROM image format may prevent a game from |
| 38 | being emulated correctly without special code to recognize that |
| 39 | game. This occurs quite often with many Koei MMC5(iNES mapper 5) |
| 40 | and MMC1(iNES mapper 1) games in the iNES format. FCE Ultra identifies |
| 41 | and emulates some of these games based on the ROM CRC32 value. |
| 42 | |
| 43 | - The ROM image may be encrypted. The author of SMYNES seems to |
| 44 | have done this intentionally to block other emulators from |
| 45 | playing "SMYNES only" games. |