Re: How do I disable elaboration code on this

[Ludovic Brenta <ludovic@ludovic-brenta.org>]

Simon Wright <simon@pushface.org> writes on comp.lang.ada:
> Jeffrey Carter <spam.jrcarter.not@spam.not.acm.org> writes:
>
>> On 04/09/2011 06:58 AM, Lucretia wrote:
>>> The following code will not compile no matter what I do. Basically, I
>>> want to write the startup code for Cortex-M3 in Ada with no assembly.
>>> So, the ISR code needs to be elaboration free as it's the first bit of
>>> code that would run on reset.
>>
>>>     Vector : constant Vectors :=
>>>       (Dummy'Access,
>>>        Dummy'Access,
>>>        Dummy'Access,
>>>        Dummy'Access);
>>>     pragma Convention (C, Vector);
>>>     for Vector'Address use Addr;
>>
>> I think what you need here is
>>
>> Vector : constant Vectors;
>> pragma Import (Ada, Vector);
>> for Vector'Address use Addr;
>>
>> since you don't want Vector to be initialized.
>>
>> Vector will not be initialized because you have pragma Import for it.
>>
>> Note that you don't need procedure Dummy.
>
> But the real code will have actual ISR procedures. OP is merely sparing
> us the unnecessary detail of the real ISRs.

But the vector being in Flash ROM, the Ada code needs not and indeed may
not initialize it, so I think Jeffrey's reply is correct.  The pragma
Import and the address clause will make the actual vectors (in ROM)
visible to the Ada program.

-- 
Ludovic Brenta.