[Tinyos-devel] Crc interface buffer size restriction

[Andreas Köpke]

Vlado Handziski wrote:
> On Tue, Jan 13, 2009 at 11:07 PM, Philip Levis <pal at cs.stanford.edu> wrote:
> > On Jan 13, 2009, at 1:41 PM, Philip Levis wrote:
> >
> > One other thought: if you want a 16-bit length CRC interface, chances
> > are you want it to be split-phase, due to the possible time duration
> > of the operation.
>
> There are also alternative table look up versions in the eyesIFX folder
> that can be useful.
>

However, the table lookup is only twice as fast as the current default 
implementation, which itself is an 10 times improvement over the original bit 
shift for loop. You might want to do time measurements before deciding whether 
it should be split phase: the LPL channel check for telosb takes 11ms in an 
atomic block, and the 64bit multiplication of the default random number 
generator takes about 1ms in an atomic block. So I guess we can spare the 1ms 
for 16bit CRC in an non-atomic block easily.

Best, Andreas