powerpc/helas403 linkcmd question

Joel Sherrill <joel@OARcorp.com> joel.sherrill at OARcorp.com
Fri Sep 10 17:29:06 UTC 2004

Smith, Gene wrote:
> Hi Thomas,
> Thanks for the quick answer!
> Since I have your ear, maybe you can answer another question regarding 
> the ppc4xx startup code. In both helas and gen405 in file dlentry.S 
> right before calling boot_card they set the stack pointer with an offset 
> of -56-4 while the helas flashentry uses just -56. What is the 
> significance of the -4 in the dlentry's?  The comments don't explain the 
> -4 (or lack of -4 in flashentry for helas).  Also, I assume the 56 is a 
> stack framesize? (I am just now learning about this ppc thing. :) )

Just to be a little begging... it really would be nice to get the
4xx PowerPCs converted over to the new interrupt model.

That would only leave a few 60x BSPs left on the old exception
model to deal with and then the old model could die.


> -gene
> Thomas Doerfler wrote, On 9/9/2004 11:00 AM:
>> Hello Gene,
>> hmmm, I should know that because I adapted the ppc403 support to my 
>> helas403 board, but actually... I have no idea.
>> I guess, I used the first 64kByte for a debug monitor and therefore 
>> relocated the vectors a bit up in the memory map. The PPC4xx family 
>> has the ability to relocate the vectors on any 64k boundary.
>> I don't see any reason to leave it there, so feel free to remove the 
>> ".fill" section. Just make sure you move the ".vectors" section by 64k.
>> wkr,
>> Thomas.
>>> I was wondering if anyone knows why the helas403 bsp linkcmds skips 
>>> over the beginning 64k of ram before locating the vectors section at 
>>> 0x00010100?  It says it is "IMPORTANT" but not why. Is this just 
>>> something specific about the helas403 board? I plan to just locate my 
>>> 405gpr vectors section at 0x00000100 like the gen405 seems to do.
>>> Thanks,
>>> -gene
>> --------------------------------------------
>> IMD Ingenieurbuero fuer Microcomputertechnik
>> Thomas Doerfler           Herbststrasse 8
>> D-82178 Puchheim          Germany
>> email:    Thomas.Doerfler at imd-systems.de
>> PGP public key available at: http://www.imd-
>> systems.de/pgp_keys.htm

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