jEnesisDS is a Genesis/Megadrive emulator for the Nintendo DS.

Author release notes:

As promised, here is the updated version with the newer cpu core. I decided to split the HW and SW renderer versions, because it makes my life a bit easier…

The SW renderer version is included as a separate binary in this release and features 2 different scaling types: “Jitter” might look better for action games, “Blend” mostly makes text more readable.

There is also a new option in the HW renderer: Force Update

If enabled, it reduces the chance of tile corruptions, but can also lead to massive slowdowns, if a game updates more tiles than the DS can handle in rapid succession. So “off” is basically faster. You can however switch to “on” temporarily, if the tiles got corrupted to force a one-time update (Viewpoint).

http://www.dcemu.co.uk/vbulletin/showthread.php?t=68175&page=4