calculate power of float number

I try to calculate y=2.5^x. y([0,2048)) is output which is 11 bits 
positive int and x([0,8)) is 6 bit which will fixed-point with 3 digits 
decimal and 3 digits fractional.


I write this module;

module prime(
    input [5:0] x,
    output [10:0] y
    );
    assign y = ((5'b11001)/(4'b1010))**( x / (10'b1111101000));
endmodule

RTL scheme : https://hizliresim.com/1ploYN

But it did not work. Also, I upload RTL scheme, x is not attached.
What is the reason for this? Could not verilog make a calculation with 
float numbers with this method?