How to measure distance between two data

thanks kaz , y really helped me

first i tried to make vhdl code for dual port ram because i will compare between two samples ..is it right thing???

but i have a problem when i tray to test the test bench is (all generics must take a default value) here is code i need your help...

library ieee;

use ieee.std_logic_1164.all;

use ieee.std_logic_unsigned.all;

entity bram_tdp is

generic (

DATA : std_logic_vector (0 to 6) ;

ADDR : std_logic_vector (0 to 6));

port (

-- Port A

a_clk : in std_logic;

a_wr : in std_logic;

a_addr : in std_logic_vector(6 downto 0);

a_din : in std_logic_vector(6 downto 0);

a_dout : out std_logic_vector(6 downto 0);

-- Port B

b_clk : in std_logic;

b_wr : in std_logic;

b_addr : in std_logic_vector(6 downto 0);

b_din : in std_logic_vector(6 downto 0);

b_dout : out std_logic_vector(6 downto 0)

);

end bram_tdp;

architecture rtl of bram_tdp is

-- Shared memory

type mem_type is array ( 6 downto 0 ) of std_logic_vector(6 downto 0);

shared variable mem : mem_type;

begin

-- Port A

process(a_clk)

begin

if(a_clk'event and a_clk='1') then

if(a_wr='1') then

mem(conv_integer(a_addr)) := a_din;

end if;

a_dout <= mem(conv_integer(a_addr));

end if;

end process;

-- Port B

process(b_clk)

begin

if(b_clk'event and b_clk='1') then

if(b_wr='1') then

mem(conv_integer(b_addr)) := b_din;

end if;

b_dout <= mem(conv_integer(b_addr));

end if;

end process;

end rtl;