Convert a binary representation to IEEE floats

ieee.erl

%% K - number of bits to represent `exp`,
%% N - number of bits to represent `frac`.
%% | s | exp(k bits) | frac(n bits) |

make_float_converter(K, N) ->
    Bias = math:pow(2, K-1) - 1,
    Max_denom = math:pow(2, N),
    Max_exp = round(math:pow(2, K) - 1),
    
    fun(<<S:1, Exp:K, Frac:N>>) ->
            case Exp of
                0 -> E = 1 - Bias,              % denormalized
                     M = Frac / Max_denom,

                     math:pow(-1, S) * M * math:pow(2, E);
                Max_exp -> case Frac of         % special cases
                          0 -> case S of
                                   0 -> pos_infinity;
                                   1 -> neg_infinity
                               end;
                          _ -> nan
                      end;
                _ -> E = Exp - Bias,            % normalized
                     M = 1 + (Frac / Max_denom),
                     math:pow(-1, S) * M * math:pow(2, E)
            end
    end.

%% Usage:
%% ======
%% F = ieee:make_float_converter(2,2).
%% F(<<2#01011>>).