[U-Boot-Users] AT91RM9200 -> UBoot and arm/thumb interworking

Thu Jul 15 09:47:18 CEST 2004

In message <200407142030211.SM00572 at ENG2> you wrote:
> 
> I'm getting started with an AT91RM9200 development kit from atmel and am
> having trouble starting a simple application with UBoot. If I compile my
> application into 32bit arm code only, I can successfully load and run some
> simple startup code through the 'loadb' and 'go' commands that UBoot offers.

What do you mean with "startup code"?

> I have two files: startup.s and main.c. "startup.s" does nothing more than
> set up some vector branches, initializes a stack, and jumps to main. All

Ummm... Whay are  you  doing  this?  U-Boot  provides  a  standard  C
environment  to  you, no special startup code is needed. Did you find
the code in the examples/ directory? This shows what you need to  get
a standalone application running under U-Boot.

> I was wondering if there was some initializations made by UBoot that would
> prevent it from loading thumb code. Any help/ideas would be especially
> useful. Thanks. 

Well, if you mess with  the  environment  like  stack  and  exception
vectors  etc.  you should not be surprised when U-Boot is crashing on
you.

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And please, don't post HTML.

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
I have a very small mind and must live with it.    -- Edsger Dijkstra