It seems like oss.sgi.com is up and running again - the
/pub/linux/mips/doc/ABI/ should have most of what you might need.

I have put the stuff I was able to find there..

I placed what small amount of material I have at
http://www.unidial.com/~neuroinc/index.html

Hm.. this was *interesting*.  I haven't seen this 64-bit MIPS psABI.  Is there
any chance that I can my hands on a postscript of them?  Maybe you could
provide a tar.gz of the HTML documents...

Ulf