http://web.archive.org/web/20010116175000/http://www.altera.com/html/mega/m-lx-5280.html
http://web.archive.org/web/20010116175000/http://www.altera.com/html/mega/m-lx-4180.html

So, it would seem the 5280 is able to run 4180 code without change.  In 
this case, there is probably enough information in the linux-mips diffs 
I posted earlier to be able to get NetBSD working properly on the Lexra 
core.

Is there any assembly code in the common MIPS code in NetBSD that uses 
the 4 patented instructions?  It'd be nice to ensure GCC never emits 
them for all the other compiled code.