From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Sun, 10 Feb 2013 13:56:28 +0100 (CET) Received: from localhost.localdomain ([127.0.0.1]:36149 "EHLO linux-mips.org" rhost-flags-OK-OK-OK-FAIL) by eddie.linux-mips.org with ESMTP id S6824793Ab3BJM41UemYA (ORCPT ); Sun, 10 Feb 2013 13:56:27 +0100 Received: from scotty.linux-mips.net (localhost.localdomain [127.0.0.1]) by scotty.linux-mips.net (8.14.5/8.14.4) with ESMTP id r1ACuQ1P014520; Sun, 10 Feb 2013 13:56:26 +0100 Received: (from ralf@localhost) by scotty.linux-mips.net (8.14.5/8.14.5/Submit) id r1ACuPeo014480; Sun, 10 Feb 2013 13:56:25 +0100 Date: Sun, 10 Feb 2013 13:56:25 +0100 From: Ralf Baechle To: folkert Cc: linux-mips@linux-mips.org Subject: Re: prom start Message-ID: <20130210125625.GA32552@linux-mips.org> References: <20130206160508.GR2118@belle.intranet.vanheusden.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130206160508.GR2118@belle.intranet.vanheusden.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-archive-position: 35732 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ralf@linux-mips.org Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips Return-Path: On Wed, Feb 06, 2013 at 05:05:10PM +0100, folkert wrote: > Is this mailing list also meant for generic mips questions? (if not: any > suggestions for one that is?) > > If so: I'mm experimenting a bit with mips, specifically on SGI hardware > (Indigo). Now it seems all mips systems have the prom at 0xbfc00000. But > how does it start? The first 0x3c0 bytes seem to be nonsense. Somewhere > on the web I found that 0xbfc00884 is the starting point but after > single stepping 5 instructions, the program counter jumps to 0x00000000 > so I don't think that's the right one either. Also, reading the first 4 > bytes from bfc00000 and using that as a pointer seems to be invalid too: > 0bf000f0. > Anyone with insights regarding the booting of the prom on sgi systems? All MIPS processors start execution at 0xbfc00000 after a hardware reset or NMI. 0xbfc00884 is not an address that has any specific meaning in the processor architecture itself. I think it's being used in the GXemul documentation just for sake of an example. If your disassembler defaults to like MIPS I / R3000 it won't disassemble all instructions for the MIPS III R4000 processor. I'd expect some cache initialization code right at 0xbfc00000 and that could would be affected. Ralf