`timescale 1ns / 1ps
//////////////////////////////////////////////////////////////////////////////////
// Company:
// Engineer:
//
// Create Date:    21:23:40 11/05/2018
// Design Name:
// Module Name:    counter
// Project Name:
// Target Devices:
// Tool versions:
// Description:
//
// Dependencies:
//
// Revision:
// Revision 0.01 - File Created
// Additional Comments:
//
//////////////////////////////////////////////////////////////////////////////////
module counter #(parameter max=10'd30) (
    input rst,
    input clk,
    input load,
    input [5:0] initVal,
    output [5:0] cout
    );

localparam nff = clogb2(max);
reg [nff-1:0] cnt;
reg [nff-1:0] initValCopy;

function integer clogb2(input [5:0] value);
begin
    value = value - 1;
    for (clogb2 = 0; value > 0; clogb2 = clogb2 + 1)
        value = value >> 1;
end
endfunction

always @(posedge clk, posedge rst)
    if (rst)
        cnt <= {nff{1'b0}};
    else if (cnt == {nff{1'b0}})
        cnt <= initValCopy;
    else
        cnt <= cnt - 1;

always @(posedge clk, posedge rst)
    if (rst)
        initValCopy = {nff{1'b0}};
    else if (load)
        initValCopy = initVal;

assign cout = cnt;

endmodule