powerpc/helas403 linkcmd question

Smith, Gene gene.smith at siemens.com
Thu Sep 9 22:56:50 UTC 2004

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. :) )


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.
> --------------------------------------------
> IMD Ingenieurbuero fuer Microcomputertechnik
> Thomas Doerfler           Herbststrasse 8
> D-82178 Puchheim          Germany
> email:    Thomas.Doerfler at imd-systems.de
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