2's complement of Zero

[PatR]

My question is deals with the output of the ALU when all the control bits ( zx, nx, zy, ny, f, no ) are set to 1. I think the output should be 0 since it's two's complement is 0. I guess I'm missing something.

[PatR]

I think I found the answer in the previous post. The function specifies bit-wise negation. Not the 2's complement of the input.