Martin Husemann said;

> > I recommend you to read a nice book;
> >     Curt Schimmel,
> >     UNIX System for Modern Architecture,
> >     ISBN 0-201-63338-8.
> 
> I can strongly second this recomendation - it is a very good book.
> 
> (Though it does not solve the MIPS version puzzle in my mind)

It's simple.
- The cause is zeroing KSEG0 of PA.  This can not avoid to
 _make_ virtual alias condition in VA indexed cache.
- The code we have seems to try compensate it by wbinv().  The simple
rule is it's best not to make virtual alias.

Toru Nishimura/ALKYL Technology