DSx86 is a PC emulator for Nintendo DS. It’s purpose is to allow you to run old DOS games on your Nintendo DS game console.

Changes:

New IRQ handling using self-modifying code, which makes the whole emulator about 8% faster than before. More info in my previous blog post.
Keyboard handling changed to support extended key codes. This will allow the mapping of some new keys like the right control key to an NDS button. Again more info in my previous blog post.
Screen update mode “Direct” was removed. It was only used in the MCGA mode, and it only speeded up certain games (Wing Commander series, mostly) by a small amount. Having that mode around meant I had to write double code for all MCGA/VGA graphics memory and BIOS operations, so now I finally got fed up with doing that.
AdLib emulation changed from effective 13-bit waveforms to 15-bit waveforms (and full 16-bit with rhythm instruments), which means that AdLib audio now has quadruple volume.
AdLib rhythm instruments (Bass Drum, Snare, HiHat, TomTom, Cymbal) implemented.
Covox/Disney Sound Source/Parallel port DAC audio device emulation added. Thanks sverx for the idea!
Sound Blaster Direct DAC audio output mode supported (SB DSP command 10).
Sound Blaster auto-init 8bit DMA audio output mode supported (SB DSP commands 1C, 48 and DA).
Fixed the BLASTER environment variable to state the SB type as T3 (SB 2.0) instead of T4 (SB Pro 2.0), as only mono audio is supported. Some games (Hocus Pocus, for example) attempted to use stereo FM sound when the type was T4, resulting in no AdLib audio.
Graphics problems in Gods are fixed.
Some new EGA opcodes added.

http://dsx86.patrickaalto.com/