Re: vhpt_miss handler question?

Mario Smarduch
2003-09-26T15:41:13Z

Keith Owens wrote:

> On Fri, 26 Sep 2003 09:43:55 -0500,
> Mario Smarduch <cms063@email.mot.com> wrote:
> >Some work I'm doing has taken me to the vhpt_miss
> >handler. I've been looking at the following snippet just
> >wondering what happens in the case where the present
> >bit is 0 and p10,p11 predicates are not set anotherwords
> >they retain their application values. Would this not
> >cause an errant insertion if either p10 or p11 were
> >true in the application prior to the VHPT handler?
>
> >(p7) tbit.nz.unc p10,p11=r19,32 // is it an instruction
>
> tbit.xx.unc sets both predicates to 0 if the controlling predicate is
> false. See the 'else' clause on page 3:229 of Document Number:
> 245319-004 (ia64 Volume 3: Instruction Set Reference).

I understand the unc sets bot predicates to 0. The question
was regarding p7úlse, but it appears in that case a TLB
entry with present bit set to 0 may be inserted which appears
to be harmless (other then taking up a TC entry).

Sorry for the noise :)

- mario.