Re: How do I disable elaboration code on this

[Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP>]

On 2011-04-11, Simon Wright <simon@pushface.org> wrote:
> Lucretia <Lucretia9000@yahoo.co.uk> writes:
>
>> The problem has nothing to do with the linker, I'm using binutils and
>> gnat that I'e built myself. The problem is that GNAT is generating
>> elaboration code where it is not allowed, i.e. code that 1)
>> initialises  the array to 0 and 2) code that the copies function
>> addresses into the array.
>>
>> If this cannot work then I'm surprised and I'll be forced to use
>> separate constants as noted by Rolf. It just seems like overkill
>> having to specify each element separately when an array is the right
>> structure ffor the job.
>>
>> And in other languages like C it doesn't do the same thing. You can
>> specify a static constant array and it'll initialise it with the right
>> data.
>
> And can you also specify the load address?
>

On Cortex M3 devices using C, this array is placed in it's own section
and is placed at address 0 by the linker script.

The issue here is that when the Cortex M3 comes out of reset it reads,
and loads, the stack pointer from the first longword in that array
and then jumps to the address specified by the second longword.

To Luke: are you targetting only the Cortex M3 or traditional ARM7
devices as well ?

If you are targetting the latter as well, you may wish to think about
just using a wrapper as you would need to have assembly wrappers anyway
for the ARM7 device. (For anyone here unfamiliar with ARM7 devices, when
traditional ARM7 devices come out of reset, you cannot even run C code
until you have setup a SP in the startup code).

Simon.

-- 
Simon Clubley, clubley@remove_me.eisner.decus.org-Earth.UFP
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