Function 'exp' not supported for fixed-point conversion. Function 'fft' not supported for fixed-point conversion.

I am trying to convert my Simulink model to fixed point, however I stuck at one block as limitation of Simulink.

Can you please provide the workaround for this..

Error is

Function 'exp' not supported for fixed-point conversion.

Basically fixed point conversion not happening for exp,log.fft,ifft functions.

Eg: for below function also attaching the same functional block.

function x_uv_dft =DFT(x_uv)

%n_ifft = info.FFTsize ;

x_uv_dft = complex(zeros(839,1),zeros(839,1));

%X = zeros(839,1); % pre-allocate result

for k = 1:839

x_uv_dft(k) = 0;

for n = 1:839

x_uv_dft(k) = x_uv_dft(k)+(x_uv(n)*exp((-1j)*2*pi*(n-1)*(k-1)/839));

end

end

end