Re: Question about caching

[Ignatios Souvatzis <is%netbsd.org@localhost>]

On Thu, Aug 27, 2009 at 07:43:16PM +0000, Michael van Elst wrote:
> agrier%poofygoof.com@localhost ("Aaron J. Grier") writes:
> 
> >On Thu, Aug 27, 2009 at 11:03:55AM -0700, Jason Thorpe wrote:
> >> Ping?  Does no one else remember either? :-)
> 
> >wow, MMU _and_ cache!  :)
> 
> >which 68k variants we talking about here?
> 
> Every single 68k that runs NetBSD.
> 
> To answer the question, the chip should generate the bus cycles
> that you ask it for. If you use a mapping that inhibits caching
> then you get 1:1 bus cycles, if you use a mapping that allows
> caching you get cache fill and push cycles. Using two mappings
> to the same physical address but with different cache modes
> rarely makes no sense.

... but would work on 68040 at least, if you insist.

        -is