SunPlus released sources for the C compiler. It doesn't include the assembler and is based on GCC 2.95 so quite hard to compile: https://github.com/vsmile-dev/unsp-gcc

µ'nSP IDE is the official IDE for the CPU used. It can still be downloaded from GeneralPlus website - local copy

XASM is the original assembler provided by the µ'nSP IDE

naken_asm has support for µ'nSP and provides a standard include file for SPG200 registers.

Work in progress patch to add µ'nSP support in vasm. There are problems in vasm handling the pure 16-bit CPU, I have asked the vasm developers for help solving that.

This early homebrew experiment took an interesting approach of not using an assembler at all.

• MAME has good support for the V.Smile.
• Unununium is a standalone emulator, but is known to have some bugs.
• https://github.com/Schnert0/VFrown - A more up to date and maintained standalone emulator

* https://github.com/gameblabla/png2vsmile - PNG converter to VSmile background bitmap format