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.

Release notes:

This version has a lot of minor fixes and improvements. There are about 50 new graphics (and normal) opcodes supported, including the 386-specific long conditional jumps. The problematic debugger breakpoint interrupt INT 03 has been adjusted so that it is silently ignored if a DOS program does not handle it and if the DSx86 inbuilt debugger is not active. I also fixed the IRQ handling, and added a debugger E command, as mentioned in the previous blog post. If you are feeling very adventurous, you can (at least in theory) use the new E command to replace an unsupported opcode with a NOP opcode (hex code 0x90) and then possibly continue a game has crashed with an unsupported opcode. This however needs a lot of knowledge about the x86 assembly language, and is not “supported”…

http://dsx86.patrickaalto.com/