library IEEE;
use IEEE.STD_LOGIC_1164.all;
entity encoder1 is
port(
a : in STD_LOGIC_VECTOR(3 downto 0);
b : out STD_LOGIC_VECTOR(1 downto 0)
);
end encoder1;
architecture bhv of encoder1 is
begin
process(a)
begin
if (a="1000") then
b <= "00";
elsif (a="0100") then
b <= "01";
elsif (a="0010") then
b <= "10";
elsif (a="0001") then
b <= "11";
else
b <= "ZZ";
end if;
end process;
end bhv;