[Oberon] Re. Active Oberon on ARM CPUs
bernhard at aces.snu.ac.kr
Thu Apr 19 06:00:03 MEST 2007
> Sven Stauber wrote To: <oberon at lists.inf.ethz.ch>:
>> In about two weeks, I'm going to work again on a project which uses the
>> ARM version of AOS. At that time, I will provide an image that runs on
>> XScale PXA25x/PXA26x CPUs (maybe also others, I'm not sure) and the
>> corresponding sources for those who are interested. I'm going to
>> announce the availability of these files on this list.
> Yes very interested, but this would be a much bigger task than porting
> ETH-oberon or AOS to a standard PC.
AOS/Bluebottle on ARM has existed for almost 6 years now as I have originally
ported the (x86) AOS to a DNARD computer with a StrongARM processor. If you're
interested, here's a link to my thesis and the sources:
The release also includes the ARM backend for Paco.
The DNARD has a OpenFirmware that Aos relies on to detect devices, switch video
modes, etc, so that release will not work 1:1 on a standard ARM board.
I've ported the initial ARM Aos for the DNARD to a simple ARM-based board with
flash memory, video output and Bluetooth. You can download the modified bootup
code/kernel for this version here
The code generated by the Paco's ARM backed will run on any ARM architecture >=v4.
> Since I've resisted examining the [family of] ARM CPU[s] architecture,
> I don't even know how/where a boot/reset code would run.
It's stored in flash memory that is mapped into the memory address space at
0x00000000. ARM CPUs start executing from there when powered up.
> Apart from any AOS considerations, where would one get
> documentation for the boot/load method. Which I'd want
> to test, in a minimum way first.
I suggest you have a look at the bootup code in wear.AosSysSrc.zip, specifically
wearARM.Relocator.Mod and ARM.AosBoot.Mod. Those are the two modules that bring
the board into a specific state. The kernel above is +/- the same for all boards
(except device drivers, of course)
Since I have left, ETH has been working on new ARM-based projects, so you might
want to wait for Sven's release. However, since documenting stuff is not one of
the strong sides of us, you might wanna have a look at my diploma thesis to get
an idea what's going on.
If you have any questions, I'll be happy to answer them.
Hope that helps,
More information about the Oberon