Re: [ECOS] scheduler and clock question

[Jonathan Larmour <jlarmour at redhat dot com>]

Arnaud Mouiche wrote:
> 
> first, tell me if I'm right :
> 
> - the object 'Cyg_RealTimeClock' defined in the 'clock.cxx' files has an
> ISR. this ISR is called regulary (10 ms corresponding to the
> CYGNUM_KERNEL_COUNTERS_RTC_PERIOD value, generally equal to
> CYGNUM_HAL_RTC_PERIOD.)
> - to create this periodicaly call, it use 'hal_clock_initialize' and
> 'hal_clock_reset' specifics functions.
> - the ISR attachement is performed by the 'Cyg_RealTimeClock' constructor
> - every CYGNUM_KERNEL_SCHED_TIMESLICE_TICKS times an ISR rise for the timer
> (generally equal to 5), a call is made to the choosen scheduler object.
> this scheduler performs context switch and so..

Yes, all right. Although note it's the DSR (invoked after the ISR) that
does the work.
 
> Here my question :
> 
> There is no header defined for  'Cyg_RealTimeClock'  object. And there is
> no link with this object in any other files. In that case, who initializes
> this object (and so, who calls the contructor) ?

It's a static object, so once the file is linked in for any reason (which
it will be if the scheduler is used), then the constructor will be called
at system startup time.

Jifl
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