I was about to say the same thing as Sven.
I had a contract where my client was using the ubiquitous AT91SAM9260 from Atmel, based on ARM926, an ARMv5 architecture, running Linux. I had to circumvent the MMU from user-mode to get real-time control of the system clocks and GPIO ports.
For anyone interested, you can see from the specification of ARMv5, both in a diagram and a statement, that MMU support is available at least since ARMv5:
"The ARM926EJ-S processor features an MMU, allowing for the use of fully featured OS such as Linux, Windows CE, and Symbian."
http://www.arm.com/products/processors/classic/arm9/arm926.php
You can also infer from using Visual Studio 2008 and earlier that Windows CE (Windows Mobile), which requires MMU support, needs no more than an ARMv4 architecture. You can see this by creating a sample Windows CE application using Visual Studio 2008, then looking at the instruction set that the compiler can target, which includes ARMv4/ARMv4i, both providing MMU support.
On a related matter, using the tool at the link below, it is theoretically possible to develop user-mode applications using only Visual Studio 2005/2008/2012 for ReactOS running on Raspberry Pi almost entirely without owning a Raspberry Pi, and, oddly, without having ReactOS installed in anywhere:
http://msdn.microsoft.com/en-us/library/bb630224.aspx
The idea would be to use only those Win32 API functions that are identical between "Little Windows" (Windows CE) and "Big Windows" (95, 98, 2000, etc.), which is surprisingly, quite a bit, including File I/O, Multi-Threading, Synchronization [no waitable timers but mutexes, semaphores, events, etc], GUI, and TCP/IP sockets. Here is the MSDN page for CreateSolidBrush, for example:
http://msdn.microsoft.com/en-us/library/aa931351.aspx?ppud=4
And sendto:
http://msdn.microsoft.com/en-us/library/ms911744.aspx
And here are the MSDN pages for CreateProcess and CreateThread, respectively:
http://msdn.microsoft.com/en-us/library/ms885182.aspx
http://msdn.microsoft.com/en-us/library/ms885186.aspx
Then, once the application is developed, it would simply be recompiled (re-linked technically) against ReactOS libs (kernel32.lib, user32.lib, etc.) instead of the Windows CE API (coredll.lib, etc.):
http://msdn.microsoft.com/en-us/library/aa448387.aspx
This re-compilation (re-linking) could be done very late in the development stage of the mobile application, after the GUI has been perfected, etc...all under the ARM emulator that comes with Visual Studio 2008. Of course, if you are doing robotics, or something like that, and need access to GPIO, etc...:(
To summarize, if anyone is interested in developing Windows-like application for Raspberry Pi, there is no need to wait until ReactOS is fully-ported to Raspberry Pi. Both types of development, OS and applications, can happen in parallel, right now, using Visual Studio. But someone really should streamlines this process, document it, and publish it so that we are all not re-inventing wheels. ;)
Cheers,
-John
-----Original Message-----
From: ros-dev-bounces@reactos.org [mailto:ros-dev-bounces@reactos.org] On Behalf Of Sven Barth
Sent: Friday, January 18, 2013 11:51 AM
To: ros-dev@reactos.org
Subject: Re: [ros-dev] ReactOS On ARM/Raspberry Pi
Am 18.01.2013 15:34, schrieb Jérôme Gardou:
> Before you put too much hope on it, ReactOS needs a Memory Managing
> Unit (basically, virtual memory support), which is present only on
> ARMv7. Raspberry Pi has an ARM11 CPU, which only implements ARMv6.
> (yeah, don't be confused with all those numberings...)
Ehm... the Raspberry Pi does have a MMU. This can already be seen because it runs full scale Linux which requires a MMU as well (unlike µLinux). MMU support for ARM was introduced at least with ARM9 (see http://en.wikipedia.org/wiki/ARM9E ).
Regards,
Sven
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