From owner-freebsd-hackers  Sun Nov 26 00:56:57 1995
Return-Path: owner-hackers
Received: (from root@localhost)
          by freefall.freebsd.org (8.6.12/8.6.6) id AAA22736
          for hackers-outgoing; Sun, 26 Nov 1995 00:56:57 -0800
Received: from cls.net (freeside.cls.de [192.129.50.1])
          by freefall.freebsd.org (8.6.12/8.6.6) with SMTP id AAA22722
          for <hackers@freebsd.org>; Sun, 26 Nov 1995 00:56:50 -0800
Received: by mail.cls.net (Smail3.1.29.1)
	  from allegro.lemis.de (192.109.197.134) with smtp
	  id <m0tJctM-0011jYC@cls.net>; Sun, 26 Nov 95 08:56 GMT
From: grog@lemis.de (Greg Lehey)
Organisation: LEMIS, Schellnhausen 2, 36325 Feldatal, Germany
Phone: +49-6637-919123
Fax:   +49-6637-919122
Reply-To: grog@lemis.de (Greg Lehey)
Received: (grog@localhost) by allegro.lemis.de (8.6.9/8.6.9) 
	id JAA13099; Sun, 26 Nov 1995 09:52:41 +0100
Message-Id: <199511260852.JAA13099@allegro.lemis.de>
Subject: Re: any eprom guru out there ?
To: graichen@julia.physik.fu-berlin.de (Thomas Graichen)
Date: Sun, 26 Nov 1995 09:52:41 +0100 (MET)
Cc: hackers@freebsd.org (FreeBSD Hackers)
In-Reply-To: <199511251452.PAA04145@julia.physik.fu-berlin.de> from "Thomas Graichen" at Nov 25, 95 03:52:53 pm
X-Mailer: ELM [version 2.4 PL23]
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 8bit
Content-Length: 1189      
Sender: owner-hackers@freebsd.org
Precedence: bulk

Thomas Graichen writes:
> 
> has anybody some deeper experience with boot-eproms and the netboot
> FreeBSD-code ? - my problem is that i want to make a boot prom for a
> smc-elite 16 plus card - the docs say: the chip is 27512 and the rom
> window size is 16k - but the 27512 is a 64k chip - now my question -
> is it possible to burn the standard FreeBSD boot-rom code (which is
> 16k by default and will fail with ROMSIZE set to 64k - due to a .word
> ROMSITE in start2.S) into the 64k eprom or can i use 16k eproms
> (27128) in the smc-elite 16 plus card ?

I'm not too sure I understand the question.  Obviously, you can fit
the bootstrap into your PROM, and it will run from a larger PROM, just
like adding another 64 MB of main memory to your machine won't stop it
from running FreeBSD.  I've had a look at the code, and it only refers
to ROMSIZE once, in order to move the contents to RAM--apparently it
executes it as a .COM file.  I don't see why this should fail just
because there's another 48 kB of empty space behind it.  Or have you
tried and failed?  Beware of setting ROMSIZE to 65536 in the Makefile,
however.  This is 16 bit code, and your .words are 16 bits too.

Greg