FACTORIAL 

A factorial (denoted by n!n exclamation mark 𝑛! ) is the product of all positive integers up to a given positive integer nn 𝑛, meaning

n!=n×(n−1)×(n−2)×…×1n exclamation mark equals n cross open paren n minus 1 close paren cross open paren n minus 2 close paren cross … cross 1

𝑛!=𝑛×(𝑛−1)×(𝑛−2)×…×1

, used to count permutations and combinations in math, probability, and computer science, with

0!0 exclamation mark

0!Defined as 1

VERILOG CODE 

module factorial_seq (

    input clk,

    input rst,

    input start,

    input [3:0] n,

    output reg [31:0] fact,

    output reg done

);

integer i;

always @(posedge clk or posedge rst) begin

    if (rst) begin

        fact <= 1;

        i <= 1;

        done <= 0;

    end

    else if (start) begin

        if (i <= n) begin

            fact <= fact * i;

            i <= i + 1;

            done <= 0;

        end

        else begin

            done <= 1;   // factorial completed

        end

    end

end

endmodule

RTL SCHEMATIC:

POWER:

TIMING: