Subject: Re: HW question & sbic sync patch
To: None <>
From: Niklas Hallqvist <>
List: amiga-dev
Date: 08/20/1994 22:06:52
>>>>> "Michael" == Michael L Hitch <> writes:

Michael> 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

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

I've already done this.  My GoldenGate II now gets mapped by the
NetBSD autoconfig much like the Zorro 3 cards or I/O-space
Zorro 2 dittos.

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

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

I have no reference on any m68k MMU.  Could you help me out, describing
what needs to be done for 68551, 68030 & 68040, respectively.