From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1DJZVl-0000KD-LU
	for qemu-devel@nongnu.org; Thu, 07 Apr 2005 12:05:46 -0400
Received: from [199.232.76.173] (helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1DJZVj-00008a-GA
	for qemu-devel@nongnu.org; Thu, 07 Apr 2005 12:05:39 -0400
Received: from [194.251.242.242] (helo=fep17.inet.fi)
	by monty-python.gnu.org with esmtp (Exim 4.34) id 1DJZtG-000378-M7
	for qemu-devel@nongnu.org; Thu, 07 Apr 2005 12:29:59 -0400
Message-ID: <42555FDB.4070501@co.inet.fi>
Date: Thu, 07 Apr 2005 19:29:15 +0300
From: Tero Kaarlela <turo.kaarlela@co.inet.fi>
MIME-Version: 1.0
Subject: Re: [Qemu-devel] Is Little endian supported by Qemu -prep
References: <4254DB0D.6060509@co.inet.fi> <1112870679.28622.96.camel@rapid>
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit
Reply-To: qemu-devel@nongnu.org
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: "J. Mayer" <l_indien@magic.fr>
Cc: qemu-devel@nongnu.org

J. Mayer wrote:

>On Thu, 2005-04-07 at 10:02 +0300, Tero Kaarlela wrote:
>  
>
>>Still working on OS/2 PPC edition bootloading. I got patch to ppc_prep.c 
>>from J Mayer to make it support non-continuous I/O map mode. It seemed 
>>to work ok. But catched bug in the further code after line mfspr 
>>r3,1008. I modified ppc_prep.c  Processor version from 0x00080000 (g3) 
>>to 0x00040000 (604) and problem was fixed. Now it crashes after code:
>>
>>  subfic r0,r0,-32690
>>  mtlr r0
>>  blr
>>  (LR = ffef7f1e)
>>  r0 was 0x00100130 to begin with
>>
>>  This error happens shortly after changinfg MSR state from 0x00000030 
>>to 0x00000031 (change mode from Big-endian to Little endian) So might 
>> Little-endian be reason why LR goes nuts?:)
>>    
>>
>
>Yes, that's the reason. As far as I know, Qemu has no support for
>dynamic endian modes.
>I did not think any OS did use LE mode...
>
Hmmm.. It seems that WinNT for PPC does run in Little-endian too...

>
>Imho, the simple way to handle this is to add a bit in the translation
>bloc state (flags in cpu-exec.c) and exend the memory access tables
>(using mem_idx in target-ppc/translate.c) for little-endian case.
>This is not so hard to do, but as all memory access routines have to be
>duplicated, it may take some time to do the patch. The great thing doing
>this way is that little endian mode will be as efficient as BE mode..
>I'll take a look during the week end and give you a patch so you may go
>on testing OS/2.
>
Thanks in advance once again :)