feat(integer): improve scalar_add #1131
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IceTDrinker
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What changed: The new code was moved into a pub(crate) function to be able to test it (and be sure that is it tested and not skipped because due to num_block/num_threads a different algorithm could be selected) |
By using the fact that one input is scalar we can speed up computation of scalar_add by packing the blocks. As the main loop as a log2 complexity, it means we just do one less iteration, but its enough to bring a 15% to 20% improvements. In other words a 64bits scalar add is as fast as a 32bit add Same idea is applicable to scalar_sub and overflowing variants
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By using the fact that one input is scalar
we can speed up computation of scalar_add by packing the blocks.
As the main loop as a log2 complexity, it means we just do one less
iteration, but its enough to bring a 15% to 20% improvements.
In other words a 64bits scalar add is as fast as a 32bit add
Same idea is applicable to scalar_sub and overflowing variants