Sequential Statements

Sequential statements run in top to bottom order
Sequential execution most often found in behavioral descriptions

Statements inside PROCESS execute sequentially

ARCHITECTURE sequential OF test_mux IS
BEGIN
    select_proc : PROCESS (x, y, selector)
    BEGIN
    IF (selector = '0') THEN
        z <= x;
    ELSIF (selector = '1') THEN
        z <= y;
    ELSE
        z <= "XXXX";
    END IF;
    END PROCESS select_proc;
END sequential;