[En-Nut-Discussion] arm port (RFC: Changing ARM mode)

[Thiago A. Corrêa]

On Tue, Jan 13, 2009 at 4:39 PM, Alain M. <alainm at pobox.com> wrote:
>
> Rocendo Bracamontes del toro escreveu:
>>
>>   void NutSleep (uint32_t ms)
>>    {
>>        ENTRY_KERNEL_MODE(); // change mode to supervisor when applicable
>>
>>       ..... code execute at kernel level here ....
>>
>>        EXIT_KERNEL_MODE(); exit supervisor mode, enter user mode when
>> applicable
>>   }
>
> I am no expert in the matter, but in my undertanding this is not very
> good. The problem is that SWI is a CALL, not a command has one parameter
> for the function and parametters have to be fetch from the user stack.
> This calls for an entire different achitecture.
>

I have no knowleadge or experience in this so far, but I can tell that
FreeRTOS follows this approach.
But it seams that they use that only in preemptive threads mode, not
with cooperative threads mode.

Kind Regards,
   Thiago A. Correa