Subject: Re: NetBSD 1.4.1 - Clock stops when doing I/O
To: Allen Briggs <firstname.lastname@example.org>
From: Michael R. Zucca <email@example.com>
Date: 01/07/2000 00:23:13
At 10:56 PM -0500 1/5/00, Allen Briggs wrote:
>Well... It's supposed to work. I haven't actually tried Linux
>itself, but I was getting totally wedged on my Q950 with the code
>that I ended up with, and I couldn't tell how it was functionally
>_any_ different from the Linux code. My next step, I think, was
>to make a fresh MacOS installation and boot linux from that--make
>sure that things are functional there, and then try again to get
>it working... I went ahead and dumped my latest code into the
>-current tree so that someone else wouldn't have to start from
>ground zero on it.
Looking closer at some Linux sites I've noticed that the IOP stuff is still
pretty much WIP. I think the floppy code is complete speculation. However,
ADB is supposed to work on the IIfx so it can't be too far off.
It's possible that the state machine programmed into the 950's IOPs differs
from the state machine in the IIfx. :-(
>That would be cool. It would probably require some more knowledge
>about the operating environment within the IOP, though I'm not sure
Odds are the IOPs are programmed just to poll the devices, dump the data
shared memory buffer and fire off an interrupt. Have you ever made an
assembly dump of the shared memory region? I noticed download/upload code
functions in the linux code. Such a dump will not only tell you where the
devices live in the IOP's address space but also how the message passing
See http://atarihq.com/danb/6502page.htm for some cool 6502 info.
>BTW, what's the current status of the color/graphics code? I haven't
>noticed/heard anything about it in a while.
It's been stalled. I recently acquired a 900 on loan from a friend so that
I have a real-live machine to do DAFB experiments on. I've been trying to
figure out what the clock frequency is for the Endeavor and to figure out
how to program DP8531 clock. I have the DP's data sheet and the circuit
Apple is using seems to be straight out of the manual but the explanations
of the registers is a bit...uh....difficult to understand :-)
Right now when I get spare moments I tinker a bit. If I get time I'm going
to see if I can bring myself to write some simple monitor detect/CLUT
manipulating graphics drivers. Now that Scott has ported wscons and I have
linux working on my PowerMac again I'm feeling more excited about
programming for NetBSD.
Michael Zucca - firstname.lastname@example.org - http://www.mdc.net/~mrz5149/
"I will choose a path that's clear. I will choose Freewill. "