Good Afternoon, Here is a patch that eeks out a tiny performance boost for the fano decoder in lib/wsprd/fano.c. It does two things:
1. It removes an ENCODE call when initializing the root node since encstate is set to zero so you know lsym will end up being zero. 2. Since the ENCODE macro is operating on 32 bits (POLY1 and POLY2 are 32 bits and the XOR based parity calcs are 32 bits) encstate in the node struct and _tmp in the ENCODE routine are changed to 32 bit integers (unsigned int), instead of unsigned long integers. This makes for slightly faster bitwise operations. With these changes I'm getting the same amount of decodes a 0.6% decrease in the time spent in the Fano decoder: === Original === 69 decodes 0.00 0.00 0.04 0.06 0.90 29.38 0.00 31.47 Code segment Seconds Frac ----------------------------------- readwavfile 0.00 0.00 Coarse DT f0 f1 0.00 0.00 sync_and_demod(0) 0.04 0.00 sync_and_demod(1) 0.06 0.00 sync_and_demod(2) 0.90 0.03 Stack/Fano decoder 29.38 0.93 OSD decoder 0.00 0.00 ----------------------------------- Total 31.47 1.00 === New === 69 decodes 0.00 0.00 0.04 0.06 0.90 29.17 0.00 31.31 Code segment Seconds Frac ----------------------------------- readwavfile 0.00 0.00 Coarse DT f0 f1 0.00 0.00 sync_and_demod(0) 0.04 0.00 sync_and_demod(1) 0.06 0.00 sync_and_demod(2) 0.90 0.03 Stack/Fano decoder 29.17 0.93 OSD decoder 0.00 0.00 ----------------------------------- Total 31.31 1.00 Given that it has to do with what instructions are used for different word sizes you might see more dramatic results on different architectures. I've also attached the scripts I used to test it out. On a related note, does anyone still have this dataset? http://physics.princeton.edu/pulsar/K1JT/wspr_data.tgz It would be nice to have some non-simulated data. 73, Ryan N2BP
test.sh
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generate.sh
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fano.patch
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