RE: IBM PPC 405 series little endian?

RE: IBM PPC 405 series little endian?

[Marti, Felix]

I don't know why you want to run the 405 in LE... but one feature that comes
in handy for me is mapping pages as LE, even though the CPU is running in
BE... this might be what you're looking for.

felix

-----Original Message-----
From: Troy Benjegerdes [mailto:hozer@drgw.net]
Sent: Monday, June 11, 2001 11:40 AM
To: Zehetbauer Thomas
Cc: 'linux-kernel@vger.kernel.org'
Subject: Re: IBM PPC 405 series little endian?


On Mon, Jun 11, 2001 at 01:34:21PM +0200, Zehetbauer Thomas wrote:
> Has someone experimented with running linux in little-endian mode on IBM
> PowerPC 405 (Walnut) yet?

Well, first, I have to ask, why??

First, if you need to deal with little endian data, on a PPC stwbrx &
lwbrx are your friends.

With the possible exception of the matrox guy, I haven't heard of ANYONE 
running in LE mode on ppc. The second problem is going to be to recompile 
ALL the applications you want and hope they work.

Finally, if you're doing anything that connects to the internet, remember 
that network byte order is big-endian. You might find it interesting that 
even Intel is now re-discovering the usefullness of big-endian in some of 
their strongarm/Xscale processors.

--
Troy Benjegerdes | master of mispeeling | 'da hozer' |  hozer@drgw.net
-----"If this message isn't misspelled, I didn't write it" -- Me -----
"Why do musicians compose symphonies and poets write poems? They do it
because life wouldn't have any meaning for them if they didn't. That's 
why I draw cartoons. It's my life." -- Charles Shulz
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IBM PPC 405 series little endian?

[Zehetbauer Thomas]

Has someone experimented with running linux in little-endian mode on IBM
PowerPC 405 (Walnut) yet?

TIA
Tom

Re: IBM PPC 405 series little endian?

[Albert D. Cahalan]

Zehetbauer Thomas writes:

> Has someone experimented with running linux in little-endian mode on IBM
> PowerPC 405 (Walnut) yet?

I doubt it. You are at least the 3rd person to want little-endian.
Somebody at Matrox posted a patch for little-endian on the 74xx.
You need a bit more than that though; you need to change the way
page table bits get set and modify head_4xx.S IIRC.

Re: IBM PPC 405 series little endian?

[Troy Benjegerdes]

On Mon, Jun 11, 2001 at 01:34:21PM +0200, Zehetbauer Thomas wrote:
> Has someone experimented with running linux in little-endian mode on IBM
> PowerPC 405 (Walnut) yet?

Well, first, I have to ask, why??

First, if you need to deal with little endian data, on a PPC stwbrx &
lwbrx are your friends.

With the possible exception of the matrox guy, I haven't heard of ANYONE 
running in LE mode on ppc. The second problem is going to be to recompile 
ALL the applications you want and hope they work.

Finally, if you're doing anything that connects to the internet, remember 
that network byte order is big-endian. You might find it interesting that 
even Intel is now re-discovering the usefullness of big-endian in some of 
their strongarm/Xscale processors.

--
Troy Benjegerdes | master of mispeeling | 'da hozer' |  hozer@drgw.net
-----"If this message isn't misspelled, I didn't write it" -- Me -----
"Why do musicians compose symphonies and poets write poems? They do it
because life wouldn't have any meaning for them if they didn't. That's 
why I draw cartoons. It's my life." -- Charles Shulz

Re: IBM PPC 405 series little endian?

[Mark Salisbury]

On Mon, 11 Jun 2001, Troy Benjegerdes wrote:
> On Mon, Jun 11, 2001 at 01:34:21PM +0200, Zehetbauer Thomas wrote:
> > Has someone experimented with running linux in little-endian mode on IBM
> > PowerPC 405 (Walnut) yet?
> 
> With the possible exception of the matrox guy, I haven't heard of ANYONE 
> running in LE mode on ppc. The second problem is going to be to recompile 
> ALL the applications you want and hope they work.

actually, we run ppc 603, 750 and 74xx series ppc's little endian in a PCI
based shared memory multicomputer.

we also run them big-endian in the VME based version.
-- 
/*------------------------------------------------**
**   Mark Salisbury | Mercury Computer Systems    **
**   mbs@mc.com     | System OS - Kernel Team     **
**------------------------------------------------**

Re: IBM PPC 405 series little endian?

[Troy Benjegerdes]

On Mon, Jun 11, 2001 at 03:08:26PM -0400, Mark Salisbury wrote:
> On Mon, 11 Jun 2001, Troy Benjegerdes wrote:
> > On Mon, Jun 11, 2001 at 01:34:21PM +0200, Zehetbauer Thomas wrote:
> > > Has someone experimented with running linux in little-endian mode on IBM
> > > PowerPC 405 (Walnut) yet?
> > 
> > With the possible exception of the matrox guy, I haven't heard of ANYONE 
> > running in LE mode on ppc. The second problem is going to be to recompile 
> > ALL the applications you want and hope they work.
> 
> actually, we run ppc 603, 750 and 74xx series ppc's little endian in a PCI
> based shared memory multicomputer.

What I should have said was 'anyone running Linux in LE mode on ppc'.

But that's also very interesting that you're running mcos in LE mode. I'm 
really curious as to why.. because PCI is little endian maybe?

Thanks.

-- 
Troy Benjegerdes | master of mispeeling | 'da hozer' |  hozer@drgw.net
-----"If this message isn't misspelled, I didn't write it" -- Me -----
"Why do musicians compose symphonies and poets write poems? They do it
because life wouldn't have any meaning for them if they didn't. That's 
why I draw cartoons. It's my life." -- Charles Shulz