On Thu, Apr 02, 1998 at 01:41:02PM -0800, William J. Earl wrote:
> > Another way to finally eleminate the virtual coherency problem from
> > KSEG0's landscape would be to actually use 8 pages as an array of
> > empty_zero_pages, so we would be able to map one wherever we want
> > such that we never run into virtual coherency trouble.
> For an always-zero page, this is the best solution. At a small
> cost in memory, you get far less overhead.
Indeed, 16ns on a 250Mhz machine for every exception that goes via the
general exception vector _plus_ the actual vce / vci handling, that sucks.
I just wonder why those exceptions have been implemented at all?
They may help somewhat in debugging operating systems, but in our situation
they're nervragging by their mere existance.