> Algorithmics Ltd of UK, one of the coolest MIPS guys on the planet,
> provides useful documents online.

For people who are serious in building MIPS processor hardwares, it's also
invaluable to obtain other docs from the company.  One of them;

  http://www.algor.co.uk/ftp/pub/hardware/p5064/p5064-user.pdf

The 84 page long PDF is a user manual for their own product, however,
it contains enormous insights beyond chip manufacturers' UM or PM.
Say, on page 30, "How ROM bytes become CPU data" depicts pitfalls on
ROM/flash programming.  Page 27 is interesting too because it provides
a definite explanation on what'd happen for "out of range memory
access."

Tohru Nishimura
Information Technology Centre
Nara Institute of Science and Technology