designing a suckless bignum library

Let's design a suckless bignum library. (I'm not part of suckless though, just curious about replacing GMP).

I researched a bit into algorithms and the rundown is this:
* long multiplication: O(n^2)
* karatsuba O(n^1.5)
* Toom-Cook, fourier transform based methods - even faster but only used for numbers 10k digits+ long. Much more complex.

So we should probably use karatsuba for all multiplications. Squaring can be done a bit faster than multiplying two different numbers sometimes.

Now I suggest programming it in assembly, that gives you access to the carry bit (C doesn't get you that). Of course we will use libc and the normal C calling conventions so that it's a regular C library.

What to do about memory management? e.g. if you want to add two numbers do we need to allocate a new 'number' as long as the largest to write the result into or do it destructively "x <- x + y"? Maybe the library should support both - then a calculator program would figure out the best primitives to use for a given computation.

It might be nice to also support things like (big modulus) modular arithmetic and polynomials. stuff like exponentiation and modular inverses have interesting algorithms.

What other integer operations would we want? I don't really want to do anything with arb. prec. real numbers - arithmetic with rationals could be done though.

>>142

fast enough in real-world usage

that's nebulous as fuck though, things that work fast enough on my gaming PC will be slow on my 7-year old laptop which wassn't even that good when I bought it. and that's a real concern because both browsers and webapps got so bloated, said laptop will be slow at basic web browsing unless I disable all the JS bullshit.

also

runs fast enough in real-world usage, can be maintained, and has a well designed feature set

isn't the whole thing synonymous with not being bloated, avoiding feature creep etc. while maintaining functionality? aka the thing I've been talking about all along.

basically, bloat isn't about SLOC. it's about feature creep, overengineering and plain old adding useless bullshit to impress the general audience.