bitwise operators on negative numbers

[Yaffle]

seems, https://github.com/justmoon/node-bignum throws an error if any a or b is a negative integer for a ^ b, a & b, a | b

The behaviour of this operators for negative integers in other libraries and in JavaScript is as if twos complement arithmetic were used. ( http://www-cs-students.stanford.edu/~tjw/jsbn/ )

I think, you might throw an error while this behaviour is not implemented

[indutny]

I'm -1 for implementing it, cc @dcousens

[dcousens]

@indutny it has always felt that negative numbers have been an afterthought (IMHO) in bn.js, thats not to say they aren't supported, but simply due to the use cases for this library being primarily crypto in a reduced context, they aren't tested/used as heavily (within reason!)
Perhaps we need to decide whether they should be first class citizens or not before we start making the APIs more cross-compatible with standard behaviour?

[indutny]

@dcousens I didn't really thought much about them indeed, and the mentioned reasons are correct. I wonder if it might be a good idea to fix it within next major bump.

btw, I think I am convinced that it should be done.

[dcousens]

@indutny if we are going to continue to support negative numbers (I think we should), then yes, it should be done absolutely.