11.2.3.4.2 8-bit Up Counter with Load and Asynchronous Reset

library IEEE;
use IEEE.std_logic_1164.all;
use IEEE.std_logic_unsigned.all;
use IEEE.std_logic_arith.all;
entity counter is
port (clk, reset, load: in std_logic;
data: in std_logic_vector (7 downto 0);
count: out std_logic_vector (7 downto 0));
end counter;
architecture behave of counter is
signal count_i : std_logic_vector (7 downto 0);
begin
process (clk, reset)
begin
if (reset = '0') then
count_i <= (others => '0');
elsif (clk'event and clk = '1') then
if load = '1' then
count_i <= data;
else
count_i <= count_i + '1';
end if;
end if;
end process;
count <= count_i;
end behave;

module count_load (out, data, load, clk, reset);
parameter Width = 8;
input load, clk, reset;
input [Width-1:0] data;
output [Width-1:0] out;
reg [Width-1:0] out;
always @(posedge clk or negedge reset)
if(!reset)
out = 8'b0;
else if(load)
out = data;
else
out = out + 1;
endmodule