function out = MyIIR(a,b,x,YStartState,sel_double)

len = length(x);

switch sel_double 
    case 0
        x = int64(x);
        a = int64(a);
        b = int64(b);
        y(1) = int64(YStartState);
    case 1
        x = double(x);
        a = double(a);
        b = double(b);
        y(1) = double(YStartState);
end

switch sel_double 

    case 0

        for i = 1:len-1       
            y_tmp(i+1) = a*x(i+1) - b*y(i)';
            y(i+1) = bitsra(y_tmp(i+1),20) + bitget(y_tmp(i+1),64);       
        end
        out = bitsra(y,16);

    case 1

        for i = 1:len-1
            y_tmp(i+1) = floor(a*x(i+1) - b*y(i)');
            y(i+1) = floor(y_tmp(i+1)/2^20) + bitget(int64(y_tmp(i+1)),64);    
        end
        out = floor(y/2^16);
end