error: Found ENDU outside of a UNION construct
    at invalid-union.asm(1)
error: Found NEXTU outside of a UNION construct
    at invalid-union.asm(2)
error: UNIONs must be inside a SECTION
    at invalid-union.asm(3)
error: Unterminated UNION construct
    at invalid-union.asm(7)
Assembly aborted with 4 errors!