error: Expected constant expression: `Known` is not constant at assembly time
    at label-diff.asm::print_diff(19) <- label-diff.asm(28)
error: Expected constant expression: `Known` is not constant at assembly time
    at label-diff.asm::print_diff(20) <- label-diff.asm(28)
error: Expected constant expression: `Unknown` is not constant at assembly time
    at label-diff.asm::print_diff(19) <- label-diff.asm(30)
error: Expected constant expression: `Unknown` is not constant at assembly time
    at label-diff.asm::print_diff(20) <- label-diff.asm(30)
error: Expected constant expression: `Known` is not constant at assembly time
    at label-diff.asm::print_diff(19) <- label-diff.asm(32)
error: Expected constant expression: `Unknown` is not constant at assembly time
    at label-diff.asm::print_diff(20) <- label-diff.asm(32)
error: Expected constant expression: `Unknown` is not constant at assembly time
    at label-diff.asm::print_diff(19) <- label-diff.asm(34)
error: Expected constant expression: `Unknown2` is not constant at assembly time
    at label-diff.asm::print_diff(20) <- label-diff.asm(34)
error: Expected constant expression: `Known` is not constant at assembly time
    at label-diff.asm::print_diff(19) <- label-diff.asm(41)
error: Expected constant expression: `Known` is not constant at assembly time
    at label-diff.asm::print_diff(20) <- label-diff.asm(41)
error: Expected constant expression: `Unknown` is not constant at assembly time
    at label-diff.asm::print_diff(19) <- label-diff.asm(43)
error: Expected constant expression: `Unknown` is not constant at assembly time
    at label-diff.asm::print_diff(20) <- label-diff.asm(43)
error: Expected constant expression: PC is not constant at assembly time
    at label-diff.asm::print_diff(19) <- label-diff.asm(54)
error: Expected constant expression: PC is not constant at assembly time
    at label-diff.asm::print_diff(20) <- label-diff.asm(54)
error: Expected constant expression: `Known` is not constant at assembly time
    at label-diff.asm::print_diff(19) <- label-diff.asm(56)
error: Expected constant expression: PC is not constant at assembly time
    at label-diff.asm::print_diff(20) <- label-diff.asm(56)
error: Expected constant expression: `Unknown` is not constant at assembly time
    at label-diff.asm::print_diff(19) <- label-diff.asm(58)
error: Expected constant expression: PC is not constant at assembly time
    at label-diff.asm::print_diff(20) <- label-diff.asm(58)
Assembly aborted with 18 errors!