SugarDS is an Amstrad CPC emulator for Nintendo DS and DSi by Nige Rideout. This version 1.5a features :

• DSi now has a full 1024K of extra CPC emulated RAM that does not interfere with the Disk/ROM memory area. DS-Lite still only has 512K of expanded CPC RAM
• Improved Z80 CPU timing - good enough now that I no longer need the old 'CPU Adjust' configuration option which has been removed
• Improved Dandanator support for poor-man 'ROMBOX' functionality. Most game compilation packs now work
• Improved disk swap so the 'ready' signal is delayed a bit which seems to improve Infocom games when swapping in/out the save disk
• Support for a single 16K Extended Upper ROM - name as Sugar06.ROM and place in /roms/bios or in the same directory as the emulator
• Added DIAGONALS as a d-pad option in configuration. General configuration cleanup
• Switched to ParaDOS 1.2 (was using v1.1)
• 1.5a hotfix to fix crash on DS-Lite when loading a new game

And if you are curious and you go check his Github profile, you will see that he has written several other emulators for Nintendo DS and DSi.