There is disagreement about whether the nature of the computation is important. Some believe that any Turing machine generating the same outputs from the same inputs as a brain has the same mind. Others argue that internal functioning - the way the calculations are performed - is important so the machine's program would have to work in the same way as the brain in order to instantiate mind.
For a thought-provoking defence of computational functionalism see David Chalmers' article on "minimal computationalism" (http://consc.net/papers/computation.html.)