Subject: Re: HW question & sbic sync patch
To: Niklas Hallqvist <>
From: Michael L. Hitch <>
List: amiga-dev
Date: 08/19/1994 08:47:48
On Aug 19,  5:25am, Niklas Hallqvist wrote:
> First of all, I have a question on how to best handle an amiga
> hardware problem:  On the A2000 the Z2 space will get cached by
> the CPU from what I've heard.  Now if one have volatile registers

  Not quite - the only Z2 space that is cached is Z2 memory.  Any
non-memory devices that autoconfigure into the Z2 memory area are
not going to be in the Memlist structures.  And since they are not
in the Z2 I/O expansion area, they will never be mapped at all by
the kernel.  It will require modification to amiga_init.c and the
configuration routines to be able to handle this.

> How about cachectl?  Is it an expensive operation to toggle

  Cachectl only deals with pushing the data cache and invalidating
the caches.  Enabling/disabling the cache done by manipulating the
CACR to control whether caching is enabled or not, or by manipulating
the cache control bit(s) in the MMU pages for a finer control (at a
page leve).


Michael L. Hitch			INTERNET:
Computer Consultant
Office of Systems and Computing Services
Montana State University	Bozeman, MT	USA