%Error: t/t_udp_bad_illegal_output.v:9:8: For sequential UDP, the output must be of 'reg' data type
                                        : ... note: In instance 'top'
    9 | output dout;
      |        ^~~~
        ... See the manual at https://verilator.org/verilator_doc.html?v=latest for more assistance.
%Error: t/t_udp_bad_illegal_output.v:16:22: Illegal value for sequential UDP line output
                                          : ... note: In instance 'top'
   16 |         1 1 ?  :  ?: *;
      |                      ^
%Error: t/t_udp_bad_illegal_output.v:17:11: There can be only one edge tigger signal
                                          : ... note: In instance 'top'
   17 |         f r 0  :  ?: 0;
      |           ^
%Error: t/t_udp_bad_illegal_output.v:18:22: Illegal value for sequential UDP line output
                                          : ... note: In instance 'top'
   18 |         0 0 0  :  ?: *;
      |                      ^
%Error: t/t_udp_bad_illegal_output.v:29:9: There should not be a edge trigger for combinational UDP table line
                                         : ... note: In instance 'top'
   29 |         r ? 1  :   1;
      |         ^
%Error: t/t_udp_bad_illegal_output.v:31:20: Illegal value for combinational UDP line output
                                          : ... note: In instance 'top'
   31 |         1 1 ?  :   *;
      |                    ^
%Error: t/t_udp_bad_illegal_output.v:33:20: Illegal value for combinational UDP line output
                                          : ... note: In instance 'top'
   33 |         0 0 0  :   *;
      |                    ^
%Error: Exiting due to