They're doing a bunch of bit voodoo. The ^ operator is XOR, '<<' shifts bits left and '&' is a bitwise AND. That's what they are in C++ at least. x = a&x ?

They're doing a bunch of bit voodoo. The ^ operator is XOR, '<<' shifts bits left and '&' is a bitwise AND. That's what they are in C++ at least. x = a&x ? a&b : c+x is a lot like the C++ shorthand if-then-else thingamabob: x = ( 1 < 0 ) ? 10 : -10; which translates to: x = 10 if 1 < 0 else x = -10. Not sure what they mean with their thingamabob though.