new processor port tips?

[Joel Sherrill]

Allan Hessenflow wrote:
> I'm working on porting RTEMS to an ARC. 
Nice to see a port underway.  What compiler and other tool versions are 
you using?

I encourage you to submit it.

>  I think I understand what needs to
> be done for the processor specific stuff in cpukit (although I know almost
> nothing about autoconf so all of the configure stuff I'm trying to just
> copy from other ports).  Is there any particular BSP I should be looking at
> as an example?  I've been looking at arm primarily because it has arm_bare_bsp
> which has stubs for the required drivers, hopefully making it easier to get
> started by letting me concentrating on just the init code.  But its linkcmds
> seem awfully complex, and it still ends up with some hard coded numbers for
> things like stack setup and where to copy initialized data to.
>
>   
Do you have a simulator for the ARC?  If so, then the first version of 
linkcmds is
the one used to link and run on the simulator.  Ditto for the start.S 
file -- it is the
crt0.s.

Using a simulator, you should then figure out how to do simple console 
output.

You 1st goal is to run hello world because it requires you to initialize 
RTEMS
and switch to the 1st thread.  Next is ticker since it adds interrupts 
to the mix.

The mips/jmr3904 and powerpc/psim BSPs can be run on simulators included
with the rtems gdb binary.  Neither has particularly difficult devices 
so should be
reasonably good references.  You can also load the tools for those, 
build them
yourself, and run them yourself.  This lets you walk through 
initialization on a
working port/BSP.  Then you know what is supposed to happen.

Use as much as you can from the simulators "libgloss" support if you are
able to test using a gnu toolchain like arc-coff or arc-elf. 

> Oh, and I'm using v4.6.6.
>
>   
Start with the CVS head. :)

--joel

> allan
>
>