activation function-taylor series in verilog

Hi.....i'm new to this verilog coding....so how i wonder if anyone can help me with this....
i'm trying to translate this arithmatic into verilo code:

verilog=x -( x³/3) + (x⁵/15)

here what i've done but it did'nt work!!

module top (a,product);

input [15:0] a;


output[15:0]product;
reg [15:0]power;
reg a_width;
reg [15:0]x,y,b,c;
reg [15:0]product;

initial begin

a_width = 1;
power=a;
end

always@(power) begin
if(a_width <= 3)
begin

power=power*power;
a_width=a_width+1;
x=power;

end

else if (a_width >3 && a_width<=5)
begin
power=power*power;
a_width=a_width+1;
y=power;
end

b=x;
c=y;
product=(a-x)+y;
end
endmodule



TQ

Your code has too many bugs. What is always@(power)?

try to use structural verilog... make code for multiplier first then connect all like this,,, :


module multiplier_fn(inp1,inp2,product);

input [31:0] inp1,inp2;
output [31:0] product;

assign product = inp1 * inp2;

endmodule



module activation_fn_2 (inp1,inp2,inp3,cin_low,cout1,out);


input [31:0] inp1;
input [31:0] inp2; //inp3=1/3
input [31:0] inp3; //inp3=1/15
input cin_low;

output [9:0] out;
output cout1,cout2;

wire [31:0] x1,x2,x3,x4;
wire [31:0] y1,y2,y3;

multiplier_fn G1 (.inp1(inp1),.inp2(inp1),.product(x1));
multiplier_fn G2 (.inp1(x1),.inp2(inp1),.product(x2));
multiplier_fn G3 (.inp1(x2),.inp2(inp2),.product(y1));
multiplier_fn G4 (.inp1(x2),.inp2(x1),.product(x4));
multiplier_fn G5 (.inp1(x4),.inp2(inp3),.product(y2));

full_subs_10bit G6 (.A(inp1),.B(y1),.cin1(cin_low),.c_out(cout1),.sum(y3)); // full substractor
rca_top G7 (.A(y3),.B(y2),.cin1(cin_low),.c_out(cout2),.sum(out)); //ripple carry adder

//im not sure how to feed inp2=1/3 and inp3=1/15,, maybe by use fixed point number for the testbench, please tell me then.
//please correct me if i do mistakes,,, thanks <faiz.omaq@gmail.com>