Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!nfsun!eklektik!danbabcock
From: danbabcock@eklektik.UUCP (/dev/ph1)
Newsgroups: comp.sys.amiga.tech
Subject: KickIt Explained (hi K.C.Lee)
Message-ID: <4661@eklektik.UUCP>
Date: 17 Jul 90 20:28:26 GMT
Reply-To: danbabcock@eklektik.UUCP (/dev/ph1)
Organization: Computers, Gerbils, and Games in the Basement, Pgh, PA
Lines: 52

Brian Moffet wrote:

>Could someone explain to me why the expansion memory to be used
>for Amiga OS 2.0 has to be the first item on the bus (on a 1000)?

[lots of good stuff deleted for brevity]

>So, why does the memory that KS 2.0 going to be loaded into
>have to be the first thing on the bus?  Is there a sort of
>bootstrap going on where a very small section of KS 2.0
>(enough to know how to deal with only 1 device is loaded)
>is used, and then as soon as it knows about the memory, it loads
>the rest into core and lets the major program take over the
>auto-config?

Yes, you're exactly right. What KickIt actually does is to hook a small
routine (one like you suggested) into ColdCapture, then do a complete
reset. The ColdCapture code is responsible for configuring the RAM card
("guaranteed" to the first device), then jumping to Kickstart 2.0. This
is actually a rather clever scheme, because it lets you fully use and test
the new Kickstart, including the autoconfig code, without requiring any
temporary hacks (well, one temporary hack - the new Kickstart has to
somehow learn about the RAM card in which it resides; I don't know how they
do that...).

>If the bootstrap scenario is the case, what would be the
>problem with making the bootstrap code understand more than 1
>device on the bus?

The problem is that the new Kickstart won't know about those other devices.
Since they are already configured, they don't respond - so the OS thinks
there isn't anything there (though it does somehow know about the first RAM
card; see the above). If you just want to play with the new Kickstart, you
can simply replace the reset/ColdCapture sequence with a JMP $200002 
(also modify the code that scans for devices so that it doesn't
reject the RAM card if it's not the first one). If you need to use other devices
(like a hard drive controller), then you have to somehow force-feed the right
stuff in one of the expansion.library lists after 2.0 is up and running. You
lose the ability to autoboot in any case. 

All these dilemas are a result of the Kickstart code residing on an
autoconfig card. If you could somehow load Kickstart 2.0 into a NON-autoconfig
card (or better a hacked autoconfig card?), all these issues would disappear.
(well, some of them?....:-))

To K.C. Lee : How's your 512K 1000 daughterboard hack coming? I'd be
happy to modify your boot ROMs for you...

-- Dan Babcock
Voice: (412)-373-1753
Internet: danbabcock@eklektik.pgh.pa.us
People/Link: DANBABCOCK