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STR912x port

Posted by Nobody/Anonymous on February 13, 2007
Hi
I think that I have found two problems with this port:
1.
See the following code in RESTORE_CONTEXT macro:
LDMFDLR, {R0-R14}^
NOP
LDRLR, [LR, #+60]
It seems that the first line corrupts the LR value used by the third one as R14==LR.
It should be:
LDMFDLR, {R0-R13}^
2. The WDG_IRQHandler calls vTaskSwitchContext for preemption. But this call only finds the next TCB without switching the context. Thus no preemption occures.

If I'm correct, what is the solution for the second problem?

Regards
Gleb


RE: STR912x port

Posted by Nobody/Anonymous on February 13, 2007
>It seems that the first line corrupts the LR value used by the third one as R14==LR.

No - the system mode lr at this point is being used as a pseudo stack pointer. If you make the change as you suggest then the lr will not be saved. It is the user mode lr that is being saved.

>The WDG_IRQHandler calls vTaskSwitchContext for preemption. But this call only finds the next TCB without switching the >context. Thus no preemption occurs.

No - read the section "Interrupt service routines" on the port documentation page http://www.freertos.org/portstr912iar.html. The STR9 port uses an alternative method.

Are you having a problem running the demo? If so what is the symptom?


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