Hi Paolo,
On Tue, Jun 20, 2000 at 03:41:08PM +0200, Paolo Mantegazza wrote:
> Pavel Andris wrote:
>
> > You may consider a problem, FP is not allowed in interrupt service routine
> > (ISR).
>
> Who said that?
>
> > The remedy is, write only a short ISR, that wakes up a RT-thread
> > (pthread_wakeup_np()) and returns. Having finished the job, the RT-thread
> > suspends itself (pthread_suspend_np).
>
> That's your idea for paying more than needed, the task switch cost.
>
> USE THE HARD FPU IN ISRs, there is no need to have a scheduler around if
> you are using a task just as a buddy of an interrupt handler.
>
I admit my opinion is not based on the study of sources but on a mail
contributed by Victor enclosed here:
--------------------------------------------------
Date: Mon, 19 Jun 2000 13:24:53 -0600
From: [EMAIL PROTECTED]
...
On Mon, Jun 19, 2000 at 11:29:57AM -0500, Shel Hoffman wrote:
> Under what circumstance is it acceptable to use floating point (FPU) in:
>
> . a interrupt service routine?
nope.
>
...
-------------------------------------------------
So, Victor, Paolo could you please make things clear for us? By the
way, in my application would ISR last several milliseconds (robot's
sample period computations, heavy use of FPU) that's why I tend to
"pay more than needed".
Regards,
pa
--
..........................................................................
Pavel Andris | tel: +421 7 5941 2167
Institute of Control Theory and Robotics | fax: +421 7 5477 6045
Slovak Academy of Sciences |
Dubravska cesta 9 | e-mail: [EMAIL PROTECTED]
SK - 842 37 Bratislava |
Slovakia |
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