Message-Id: <199509301201.FAA01914@corbin.Root.COM>
To: Bruce Evans <bde@zeta.org.au>
Cc: julian@ref.tfs.com, hackers@freebsd.org
Subject: Re: correctness of isa.c 
In-Reply-To: Your message of "Sat, 30 Sep 95 21:48:49 +1000."
             <199509301148.VAA00595@godzilla.zeta.org.au> 
From: David Greenman <davidg@Root.COM>
Reply-To: davidg@Root.COM
Date: Sat, 30 Sep 1995 05:01:03 -0700
Sender: owner-hackers@freebsd.org
Precedence: bulk

>Shouldn't pmap_mapdev() be declared in a machine-independent header and
>used in future drivers in other systems?  It has no i386 dependencies
>except for the type of a physical address.  How did old versions of BSD
>handle mapping physical addresses for device drivers?  Why doesn't VM
>distinguish between the types of physical and virtual addresses?

   It has no i386 dependencies as far as the interface of the function, but the
function itself has almost no independencies. :-)

>  How did old versions of BSD handle mapping physical addresses for device
>drivers?  Why doesn't VM

   I don't know how old versions of BSD worked in this regard. They probably
did something really VAX specific and disgusting (like plugging the page
tables in the device driver).

>  Why doesn't VM distinguish between the types of physical and virtual
>addresses?

   I don't understand this question. Different types? Do you mean kernel/user
or managed/unmanaged, or what?

-DG