Interesting. Are you also going to do 24 core SMP?

When you say "only CPU and memory", how about networking? How is data
moving between the "units"?

-xtang

-----Original Message-----
From: Duraid Madina [mailto:community-noreply@qnx.com] 
Sent: October 20, 2008 8:16 PM
To: ostech-core_os
Subject: Re: Porting QNX to new architecture: any
manuals/tips/must-reads?

> > Hi everyone,
> > 
> >   I'm investigating porting QNX to an in-house processor
architecture. 
> 
> Wow, how many years do you plan to invest in this project?  ;-)

I'd hope to have _something_ going within 6 to 12 months. But that
shouldn't be as crazy as it sounds, because:

> Do you have a working GNU Toolchain for it?

Yes, mostly. Since we have no OS running, obviously programs are limited
in what they can do currently. But we do have C/C++ compilers going,
brk(), printf(), just enough to debug stuff without an OS. But it's
starting to hurt.

> Are there some more details about your in-house CPU?

Unfortunately, there's nothing relevant to the OS side of things that
has been published. If you're curious though, the CPU is probably going
to end up being called MDGRAPE-4, it is the successor to MDGRAPE-3 you
can read about here:

http://en.wikipedia.org/wiki/MDGRAPE-3

> Does it contain a MMU?

Yes, it does. It is nothing too fancy, but it has hardware support for
dealing with TLB misses, and it also supports a number of different page
sizes. (As I hope QNX does? I'd better go have a look..)
Also, since the processor is not fixed in final silicon just yet, there
is still some time to tweak the MMU.

> The count of years will depend on some of this details.

Well, a lot of the toolchain is done. It can't be _too_ much of a
nightmare??

That reminds me of one last point: our hardware platform is pretty
"simple", in that we don't have lots of strange devices that need
drivers to be written. It's going to be memory and CPUs on the boards
and not a whole lot else.


_______________________________________________
OSTech
http://community.qnx.com/sf/go/post15288

We can run on 64bit chips, but we currently only support a 32bit model.  For example, we run on 64bit MIPS processors, 
we save/restore the full 64bit
regs, but the compiler believes that it runs in a 32bit world.

True 64bit has yet to be done... although it would be doable.

Duraid Madina wrote:
>  
>> The "services/system/doc/PORTING" document is about it as far as stuff
>> being written down.
> 
> Thanks! I completely missed this gem!
> 
>> As others have noted, you need a 32 bit CPU with a full featured MMU or
>> you're going to be in a world of hurt.
> 
> Uh oh: by 32 bit CPU, you mean "32 bits plus", right? Because our target is 64-bit. :( Or is 64-bits an absolute 
nightmare for QNX?
> 
> 
> _______________________________________________
> OSTech
> http://community.qnx.com/sf/go/post15293
> 

-- 
cburgess@qnx.com

On Mon, Oct 20, 2008 at 08:40:00PM -0400, Duraid Madina wrote:
> Uh oh: by 32 bit CPU, you mean "32 bits plus", right? Because our target 
is 64-bit. :( Or is 64-bits an absolute nightmare for QNX?

We've only done 32-bit so far. The code is supposed to handle 64 bits,
but until you've done it the first time, you know there are going to be
places that need tweaking. Doing a 64 bit version is something that we
plan to do eventually - it's always the next thing up until something 
more important comes along :-).

	Brian

-- 
Brian Stecher (bstecher@qnx.com)        QNX Software Systems
phone: +1 (613) 591-0931 (voice)        175 Terence Matthews Cr.
       +1 (613) 591-3579 (fax)          Kanata, Ontario, Canada K2M 1W8