Originally Cygne was developed by Dox as a Bandai Wonderswan (Colour)
emulator for Windows systems. From version 2.1 Dox decided to
release the Windows sources to the public in GPL form which allows
others to use the source and hack it :)

Cygne/SDL is a Cygne port using the Simple Directmedia Layer (SDL)
library.  Cygne/SDL is released as OpenSource under the GPL license.
It uses code from the orignal Cygne (allthough a bit modified),
code from the MAME NEC CPU core as well as portions from several
SDLemu emulation projects. Anybody may hack the current sourcecode
if they like or can make additional changes into it.

Homepage:
https://icculus.org/Cygne-SDL/
