This is the mail archive of the ecos-discuss@sources.redhat.com mailing list for the eCos project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: ROM and hardware vectors for ARM.


On Thu, 2002-10-17 at 08:12, Erik Aagaard Knudsen wrote:
> It is our inpression that in order to be able to debug an application on an
> ARM-target, the ROM-redboot must 
> 
> 1. Boot from adr 0x0 and initialize the CPU/Memory
> 2. Remap the system so that the boot ROM is removed from addr. 0x0 and
> replaced by RAM.
> 3. Interrupt vectors is then initialized in this new RAM at addr. 0x0
> 
> What can we do if we do not have the possibility of remapping (swapping
> ROM/RAM addresses)?

Why can't you?  What's your processor (core)?

> 
> The secondary vector table is located in the vectors section ( 0x20 up). Can

This would take some work.  The vectors assume that the secondary table 
can be reached with a PC-relative instruction, which limits how far away
the table can be - probably out of reach if it's in a different section
of memory.

> this table without too much fuss be moved to RAM instead (f.ex. into the
> fixed vectors section)? This would ofcourse mean that we have to initialize
> these RAM locations with the correct pointers, but it would mean that these
> vector pointers could be located anywhere in the memory space, hense
> removing the need for hardware remapping logic.
> 
> Are there other problems, which we have not identified?
> 

Yes, plenty of them.  Grant Edwards did this a long time ago,
he might be able to give some insight.

-- 
------------------------------------------------------------
Gary Thomas                  |
eCosCentric, Ltd.            |  
+1 (970) 229-1963            |  eCos & RedBoot experts
gthomas@ecoscentric.com      |
http://www.ecoscentric.com/  |
------------------------------------------------------------


-- 
Before posting, please read the FAQ: http://sources.redhat.com/fom/ecos
and search the list archive: http://sources.redhat.com/ml/ecos-discuss


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]