error: Base value must be equal to $FF00 for $FF00+C
    at ff00+c-bad.asm(8)
error: Expected constant expression: 'xyz' is not constant at assembly time
    at ff00+c-bad.asm(9)
error: Base value must be equal to $FF00 for $FF00+C
    at ff00+c-bad.asm(9)
Assembly aborted with 3 errors!