On 30-Sep-2001 Bart Kus wrote:
>       Right now, I use for() as a timing loop.  I calibrate it on program
start 
>  and can then get very precise timing.  There are, of course, the
>  intermittent 
>  interruptions of the multitasker.  So this solution is not ideal by any 
>  means.  In fact, the for() loop approach is really meant for the DOS port of
>  this software.  I'm wondering if there is any way I can access a more
>  precise 
>  interrupt-driven (or blocking) timing source.  I know I can do a select() 
>  with supposedly microsecond accuracy, but I doubt that it is in fact that 
>  accurate in practice (doesn't the kernel only use a 100Hz clock or 
>  something?).  Is there any way to get at the system timers on the 
>  motherboard?  Those can provide precise timing, no?

I suspect the only way you could achieve this in FreeBSD at the moment is to
write a kernel driver.

That way you can disable interrupts while you frob your board.. (And get quick
access when you need it).

---
Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum

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