LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
ENTITY p_check IS
PORT ( a : IN STD_LOGIC_VECTOR (7 DOWNTO 0);
y : OUT STD_LOGIC );
END p_check;
ARCHITECTURE opt OF p_check IS
SIGNAL tmp :STD_LOGIC ;
BEGIN
PROCESS(a)
BEGIN
tmp <='0';
FOR n IN 0 TO 7 LOOP
tmp <= tmp XOR a(n);
END LOOP ;
y <= tmp;
END PROCESS;
END opt;