libtorsion VS scc

Most of the crypto is from my more general crypto library libtorsion: https://github.com/bcoin-org/libtorsion

I originally wanted to vendor my libtorsion code and link to it, but it felt clunky since libtorsion pulls in a ton of crypto that bitcoin doesn't need. Also, since I was focusing on just a few algorithms, it gave me the opportunity to optimize a lot of them (in particular, the ECC backend was optimized for secp256k1 whereas in libtorsion it supports all kinds of curves).

Because of all of this, there's probably some leftover comments. That comment isn't true anymore. rand.c is definitely used internally for libmako, just not libtorsion.

edit: fixed link.

The 2-by-1 and 3-by-2 division functions described in the paper result in a very measurable speedup in my code. I think you're confusing those with the reciprocal calculation itself (which can be computed with a lookup table). I agree that part doesn't really lend itself to any significant performance benefit and is probably better calculated with a single hardware division instead.

I feel it necessary to point out that the 3-by-2 division actually has multiple benefits which are easy to miss:

1. The quotient loop can be skipped as I mentioned.

2. The "Add back" step is less likely to be triggered.

3. Since a 2-word remainder is computed with the division, you can skip 2 iterations on the multiply+subtract step.

My reimplementation of GMP documents both the 2-by-1 and 3-by-2 divisions pretty thoroughly[1][2].

[1] https://github.com/bcoin-org/libtorsion/blob/master/src/mpi....

[2] https://github.com/bcoin-org/libtorsion/blob/master/src/mpi....

View on GitHub

Going to say my own https://github.com/boyter/scc/ which I have used to turn down projects of "Oh we just need to do X"

It allows me to evaluate the code-base quickly and see where potential issues are, and find hidden complexity in the code. I have said no a lot due to it. The only reason it exists was because I got caught out from another project, which wasted months of my time.

Otherwise IntelliJ and the JetBrains IDE's in general.

Very cool to see this here, Ben! It was fun beating the ins and outs of your work on this in the TZ discord.

Also, off-topic but as you know, I recently tried out your scc tool and am eagerly awaiting its support for Elixir templates (.eex, .heex)!

https://github.com/boyter/scc

I believe tokei is the best rust option as of now, but despite my burning passion for rust I've switched to using scc instead as I find it faster and more convenient. Not really an option for you if you're trying to bake line counting into the binary, obviously.

I've seen some real world example where Go was as fast or faster than Rust for CPU / io intensive task.

Go is a fast language even with a GC.

https://github.com/boyter/scc/#performance

I don't trust your qualitative "LARGE" for the project. I would recommend you pass your project through something like a software metrics tool https://github.com/boyter/scc to better measure what you're up against in terms of Flutter/Dart AND Rust code base.