library ieee;
use ieee.std_logic_1164.all;

entity slice02 is
  port (di : std_logic_vector(7 downto 0);
        do : out std_logic_vector (3 downto 0));
end slice02;

architecture behav of slice02 is
  type mem is array (natural range <>) of std_logic_vector (1 downto 0);
  signal m1, m2 : mem (3 downto 0);
begin
  m1 <= (di (7 downto 6), di (5 downto 4), di (3 downto 2), di (1 downto 0));
  m2 <= m1 (0 downto 0) & m1 (1 downto 1) & m1 (2 downto 2) & m1 (3 downto 3);
  do <= m2 (1) & m2 (0);
end behav;