[U-Boot-Users] Re: Why exceptions are enabled before exception vector code is copied

Wolfgang Denk wd at denx.de
Wed Jul 6 10:04:02 CEST 2005


In message <c8f10050706004556bcca54 at mail.gmail.com> you wrote:
> 
> Can I ask you why exceptions are enabled before exception vector code
> is copied to the low RAM pages ? (I am talking about U-Boot/PPC)

No exceptions are supposed to happen until then.

> On my board, U-Boot crashes before relocation (when debugging) since
> Xilinx Microprocessor Debugger (XMD) makes a spurious "Machine Check
> Exception". For other reasons, such an exception could arrived before
> u-boot starts.

Well, then fix  this  problem.  What  do  you  suggest  hoiw  such  a
situation should be handled while running from flash?

> Finally, it is a bug or a very strange coding behaviour...

It does not happen on other systems.

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
The universe does not have laws - it has habits, and  habits  can  be
broken.




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