Hydr8gon has updated the port of the Nintendo DS Emulator to the Nintendo Switch:

melonDS was just bumped to version 0.7 a few hours ago, so here's another release from me as well! This release comes with an options menu containing four whole options (crazy, I know). I've also reworked some things to prevent flickering when navigating the menus.

The options added include:
Boot game directly - Disabling this will allow you to boot into the DS firmware instead of automatically running a game.
Threaded 3D renderer - Speeds up 3D rendering; you probably don't want to turn this off.
Vsync - While not technically being Vsync, the functionality is similar enough. Disabling this will let the screen render without waiting for a frame to finish. It'll give you a performance increase at the cost of screen tearing and minor artifacts.
Audio output - Self-explanatory. Disable to sacrifice audio for a small performance boost.

The first two options are actual melonDS options, while the last two are custom ones I added for the purpose of increasing performance. You still probably won't get full speed, and the trade-offs may or may not be worth it, but at least it's something.

This release fixes sound output. It was a really strange bug, but basically, there was nothing wrong with my code; I suspect either Atmosphère or Horizon itself to be at fault here. To fix it I've moved the audio process to a different core and it magically works again. This release also completely removes the audio toggle from the settings. I've determined that it has absolutely no impact on performance, so what's the point? If you still want to mute the emulator, the Switch has volume buttons. There's also one last little fix in this build that makes sure the B button can't back you completely out of the SD card. Hopefully I didn't miss anything this time!

download https://github.com/Hydr8gon/melonDS

via https://www.nintendomax.com/viewtopic.php?f=168&t=16848