Cortex-M3 support?

[Joel Sherrill]

Mike Panetta wrote:
> I have been looking at CVS head and noticed that there is no cortex-m3 support in RTEMS.  Has anyone started work on this?  If yes, is the code available somewhere?  If no, where would one start a port for this ARM core?  It does not seem to quite fit in with the current ARM code in that exception handling is somewhat different...  Would one create a cortex-m3 directory under libcpu/arm,libbsp/arm, etc, or just put the code directly in the respective arm dir for this port?  I don't think adding CPU support for this core would be such a big deal, its just figuring out where to put it... BSP support on the other hand may be another matter...
>
>   
Sebastian Huber has been reworking the ARM exception code so
make sure you are on today's head and talking to him.

In general terms, you want to start with the CPU core and
ignore the peripherals.

+ make sure the multilib variant is in the tools
+ make sure the multilib variant is properly supported
    by cpukit/score/arm and the libnetworking cksum routines.

If you have a non-RTEMS "no OS" arm-elf toolset which can
produce working executables for you, then you are almost
ready for a very minimal BSP.

+ Use the linker script as base with additions for
    workspace related symbols
+ Use the crt0.S from it (change call main -> boot_card)
+ implement a polled console using the libgloss support.
+ Use the "dummy idle task clock driver"

At the moment, I think the avr, m32c, adn m32r BSPs are the closest
examples to this minimal point.

That gives you enough to run tests with no interrupts.

Sebastian will need to step in for exception processing.

> Any help, suggestions on this would be greatly appreciated!
>
> Thanks,
> Mike
>
> _______________________________________________
> rtems-users mailing list
> rtems-users at rtems.org
> http://www.rtems.org/mailman/listinfo/rtems-users
>   


-- 
Joel Sherrill, Ph.D.             Director of Research & Development
joel.sherrill at OARcorp.com        On-Line Applications Research
Ask me about RTEMS: a free RTOS  Huntsville AL 35805
   Support Available             (256) 722-9985