Does rtems have a portable, sort-of calibrated time-wastingloop?

Joel Sherrill joel.sherrill at
Wed Mar 26 14:43:18 UTC 2003

"Eugeny S. Mints" wrote:
> Hi,
> On Tue, 25 Mar 2003 gregory.menke at wrote:
> >
> > Perhaps something like Linux's udelay- it doesn't have to be fast, but
> > should cause the program to spin for the supplied interval.  It should
> > not itself reschedule, so rtems_wake_after is out- and should be
> > callable from an isr.
> Yes, seems it is 'rtems_bsp_delay()' macro. Each bsp should
> define it in a custom way (because it is very dependent on
> the clock speed of the target). I'm not sure, wether it is
> callable from an isr but don't see any restriction for this.

Since this routine is BSP dependent, it could end up not being
callable from an ISR but that is not the intent.  It is intended
to be a tight assembly loop or poll a HW counter/timer but should
be callable from an ISR.  The only issue is killing time 
in the ISR.

> Regards,
>                         Eugeny
> --
> Eugeny S. Mints
> OKTET Ltd.
> 1 Ulianovskaya st., Petergof, St.Petersburg, 198904 Russia
> Phone: +7(812)428-4384 Fax: +7(812)327-2246
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