2^256 == 0, 2^255 == -578...

[davebryson]

In the wiki docs for Serpent, it says that anything over 2^256 will wrap to 1. Using serpent 2.0.2 I'm finding that:

2^256 == 0
2^255 == -5789604461... (note that's negative)

And anything over 2^256 == 0

Is this correct behavior or a bug?

[joeykrug]

That's correct behavior. Serpent uses signed integers by default --- see http://kias.dyndns.org/comath/13.html "if a signed integer has n bits, it can contain a number between -2^(n - 1) and 2^(n - 1) - 1"

uint256 will give you unsigned