Architecture declarations describe the operation of the component
Many architectures may exist for one entity, but only one may be active at a time
An architecture is similar to a schematic of the component
ARCHITECTURE behavior1 OF
half_adder IS BEGIN
PROCESS (enable, x, y)
BEGIN
IF (enable = '1') THEN
result <= x XOR y;
carry <= x AND y;
ELSE
carry <= '0'
result <= '0';
END PROCESS;
END behavior1;