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Fastrange: A fast alternative to the modulo reduction (github.com)
21 points by henrikm85 3473 days ago
2 comments
dmitrygr 3473 days ago
This is how we've been doing division by a constant in the embedded world since...forever

this is so well known in fact that arm gcc defaults to this when a proper constant exists if you do division or modulus operator...

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lvs 3473 days ago
I was going to say, this is an ancient and well-known optimization. I have no idea how old it is, but I would venture it's been a regular practice for at least two decades.
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rkwasny 3473 days ago
Shouldn't a good compiler apply this type of optimisations?
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AstralStorm 3472 days ago
It generally does. (GCC, Clang and ICC) But it cannot simplify the operation on some architectures or when the factor is variable.

The "fastrange" is a very different operation on prime factors than modulo.

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