http://web.archive.org/web/20141010153046/http://www.japheth.de/JWasm.html
Had forgotten about the Wayback machine...
Here you can download the latest source JWasm212s_140105:
http://www.archive-de-2014.com/open-archive/4100113/2014-06-09/06ee7a35d283f96eb77559fa05235a8c (http://www.archive-de-2014.com/open-archive/4100113/2014-06-09/06ee7a35d283f96eb77559fa05235a8c)
You just need to sign up