[ECOS] put unmask in ISR rather than DSR causing interrupt lost

[Randy <randyqiuxy@hotmail.com>]

Hi Stano & all,
>On 07.04.2013 14:06, Randy wrote:
>
>> After one ISR is over, the DSRs in FIFO queue starts to run one by
>> one like A=>B=>C=>... If one interrupt comes when B is running, then
>> what will happen?
>> If B is stoped and the new ISR is going to run,
>> then, how and when does the B come back(we may cann't use
>> "reschedule" to describe it)?
In fact, the problem I faced make me think about the interrupt model details like above.
The problem described as this mail title shows,
eCos require that we should unmask interrupt in DSR, but why would we lost any interrupt when I unmask in ISR rather than DSR?
Thanks for your advance..
>
>The processor detects the interrupt, saves the current program
>counter on the stack, looks up the table defining wich handler
>is to be run for tha particular interupt source and runs the
>handler.
>
>When this handler returns, then whatever the handler interrupted
>will continue where it was interrupted, in this case B.
>
>The exact sequence of steps is hardware- and configuration-dependent,
>the interrupt and exception handling is where the architectures
>differ significantly.
>
>> Or, could you tell me which code snippet in eCos3.0 shows the handler?
>
>This is architecture specific partly assembler code. Look for
>vectors.S and other files in your HAL, but you will only
>understand it if you have quite detailed knowledge about your
>processor. I never needed to go that deep.
>
>Regards
>-- 
>                                         Stano
>
>