mipsco kernel sources?

[Mark Abene <phiber%radicalmedia.com@localhost>]

This may be a silly question, but I can't seem to find the kernel SOURCES
for arch/mipsco in any of the NetBSD versions of syssrc.tgz I've checked.
I'd like to explore the possibility of porting NetBSD to use the RISC/OS
firmware on the Magnum 4000PC and SC.  Since we have a choice between ARC
and RISC/OS firmware on the Magnum 4000 series (and I personally feel that
the RISC/OS firmware is far superior), I wanted to look into it.

Thanks,
-Mark