Cortex-M3 support?

[Mike Panetta]

----- Original Message ----
> From: Joel Sherrill <joel.sherrill at oarcorp.com>
> To: Mike Panetta <mprtems at bellsouth.net>; "rtems-users at rtems.org" <rtems-users at rtems.org>
> Sent: Friday, July 24, 2009 10:41:21 AM
> Subject: Re: Cortex-M3 support?
> 
> Sebastian Huber has been reworking the ARM exception code so
> make sure you are on today's head and talking to him.

I don't have his email address, should it be in the list archives?
He has not posted recently in reply to this message, so I am
not quite sure how to contact 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.

Its in the tools, but the score code seems to be dependent on 
non thumb ASM so it will not compile for the Cortex-M3.

Specifically the context switching code is explicitly in ARM mode.

> 
> 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"

As soon as I can figure the best way to get the score code to
compile that will be my next step, using the rtems supplied tools. :)

> 
> 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.

Waiting to hear from him. 

> 

Thanks again,
Mike

> 
> -- 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