Re: [f-cpu] another DATE report

[Ben Franchuk <bfranchuk@jetnet.ab.ca>]

Christophe wrote:
> 
> > Indeed, to avoid this problem when task switching, the usual workaround is to
> > disable interrupts before acquiring and after releasing the spinlock. But
> such
> > a thing is acceptable if time is very short between locking and unlocking,
> that
> > is, not using a blocking function in-between.
> 
> ... is to disable interrupts JUST before acquiring and to ENABLE interrupts
> JUST after releasing the spinlock.

I have to check a book on real time programing, but this style of task
locking
may not work on multiprocessors. I think the critical section algorithms
for multi-tasking favor normal instructions over atomic ones.  Looking
at software
all you are doing is emulating edge triggered flip/flops in software and
running
asynchronous logic from them. The task switching and real time clock
sync up the tasks. 
Synchronous logic is good for hardware, why not software? 
-- 
Ben Franchuk - Dawn * 12/24 bit cpu *
www.jetnet.ab.ca/users/bfranchuk/index.html
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