Badda has released a Commodore 64 emulator to the Nintendo 3DS:

This is a port of the VICE C64 emulator to 3DS.
VICE - the Versatile Commodore Emulator - http://vice-emu.sourceforge.net/

@spinal_cord made a C64 emulator (Breadbox) based on Frodo but it does not work anymore with recent firmwares and he is not updating it anymore, so I gave it a shot to port the Vice C64 emulator v3.3 to the 3DS. Vice does support SDL1 but porting was not quite as easy as "just compile": A new sounddriver for the 3DS needed to be written, devkitpro libraries do not support all functionality required by full fledged Vice (so I had to strip them in quite some places) and lots of other things that needed tweaking or adaption.
The result is: Vice3DS

v1.3

enhancement: button to show/hide the keyboard, more soft buttons below keyboard
enhancement: pixel perfect screen representation (required change in libSDL, thanks to @Vague Rant)
enhancement: paint color keys on keyboard with palette colors
enhancement: added help menu
enhancement: remember current directory for file dialogs across restarts
enhancement: standard soft button icons are copied to SD-card at startup, they can now be modified/amended by the user
enhancement: added some more helper menu entries in menu "Misc"
enhancement: added some soft button icons
bugfix: no more freeze when exiting via home or power button
bugfix: roms added for all C64 machine types
bugfix: re-center display after machine type change
optimization: stripped some unnecessary code (vkbd, hvsc)

v1.2.1

fix random lock-ups (was actually a bug in libSDL)
fix for "not possible to select external palette files"
other minor bugfixes and optimizations

v1.2

fix for "crackling sound when using keyboard"
fix for "not possible to change back to stock rom from another rom"
fix for "menu entry 'Restore default settings' messes up screen"
added menu entry/icon 'Misc/Power off bottom screen backlight'
added two icons for sprite collision menu entries
added menu entry to restore all default settings (incl. hotkeys etc)
quicksave/-load now always saves to/loads from /3ds/vice3ds
added "RUN" to LOAD"*",8,1 menu entry
Added F2/F4/F6/F8 keys to keyboard for easy access
Added pause icon / ability to pause via soft button
Nice new banner / startup logo

v1.1

Customizeable soft buttons on bottom screen.
Changed standard assignment of autofire buttons: Joy1=R, Joy2=ZR
True drive emulation now turned off by default
Emu-speed adjustable with 3d slider (0=100%, max=Warp)
Added menu 'Misc' with some helpers: RUN/STOP + RESTORE; LOAD"*",8,1
Bugfix for loading external ROMs and other sysfiles

https://github.com/badda71/vice3ds

https://www.nintendomax.com/viewtopic.php?f=132&t=17043