Factorial of an number

Theory:--

• The factorial of a number n, denoted as n!, is the product of all positive integers from 1 to n.
  
  

• It is defined only for non-negative integers, with 0! = 1 as a special case.
  
  

• Factorials grow very rapidly, leading to large values even for small inputs.
  
  

• They are widely used in permutations, combinations, probability, and various mathematical computations.
  
  

• Factorial operations are typically implemented using loops or recursion in programming and digital logic.

Verilog Code (Behavioural Description):--

module fact_num(

    input  wire [2:0] n,

    output reg  [15:0] fact

);

integer i;

always @(*) begin

    fact = 1;

    for (i = 1; i <= n; i = i + 1)

        fact = fact * i;

end

endmodule

Test Bench:--

module tb_fact_num;

    reg  [2:0] n;

    wire [15:0] fact;

    fact_num DUT (n, fact);

    initial begin

        n = 0; #10;

        n = 1; #10;

        n = 2; #10;

        n = 3; #10;

        n = 4; #10;

        n = 5; #10;

        n = 6; #10;

  $finish;

    end

endmodule

OUTPUT WAVEFORM:--

pin assignment:

i/p=j15,l16,m13,r15

o/p=h17,k15,j13,n14,r18,u17,v17,u16,v16,t15,u14,t16,v15,v14,v12,v11