Hi,

   I am currently trying to get a recursive subroutine working for myself and it's driving me mad. It's pretty simple, all it does is trace a signal through a hierarchial tree. So pick a top level signal and see where it goes 

clk_cts
  |
  |--cts_inst1
         |--CTB02Q
  |--cts_inst2
         |--CTB02Q

[download]
etc.

Now the problem is that when I call the subroutine recursivly it only follows one tree but doesn't return to follow the other trees (ie cts_inst2). When I remove the recursive call I can see the other branches so I know that they are there. Here is the code 

sub trace_sig_down_hier {

  my $vdb=shift;
  my $module=shift;
  my $signal=shift;
  my $instance=shift;
  my $level=shift;

  print "DEBUG: $module:$module:$signal:$instance:$level\n";
  my($imod,$iname,$port,$l,@connections);


  SIG:foreach my $sig (sort &rvp::get_modules_signals($vdb,$module)) {
    next SIG if ($sig ne $signal);
    
    for (($imod,$iname,$port,$l) = 
         &rvp::get_first_signal_port_con($vdb,$module,$sig );
         $imod;
         ($imod,$iname,$port,$l) = 
         &rvp::get_next_signal_port_con($vdb)) {
      print "DC:$imod,$iname,$port,\n";
      if(&rvp::module_exists($vdb,$module)) {
        my $full_path =  $instance . "/" . $iname;
        $level++;
        my @sub_conns = &trace_sig_down_hier($vdb,$imod,$port,$full_pa
+th,$level);
        push @connections,@sub_conns;
      }
      my $sig_path;
      if ($instance) {
        $sig_path = $instance . "/" . $port;
      }else{
        $sig_path = $module . "/" . $port;
      }
      push @connections, $sig_path;
      #print "SUB : $sig_path\n";
    }
  }

  return @connections;
}

[download]
Without the recursive call (to see top level tree) this is the output: 
11:57_dcollins_HOME_[267]>./tk_verilog.pl
HL: no_gated_clk_cts_1:no_gated_clk_cts_1:
5 : clk_cts
DEBUG: no_gated_clk_cts_1:no_gated_clk_cts_1:clk_cts:no_gated_clk_cts_
+1:0
DC:cts_env_1,cts_inst,y,
DC:cts_env_1,cts2_inst,y,
DC:cts_env_3,cts3_inst,y,

[download]
And with the recursive call : 
HL: no_gated_clk_cts_1:no_gated_clk_cts_1:
5 : clk_cts
DEBUG: no_gated_clk_cts_1:no_gated_clk_cts_1:clk_cts:no_gated_clk_cts_
+1:0
DC:cts_env_1,cts_inst,y,
DEBUG: cts_env_1:cts_env_1:y:no_gated_clk_cts_1/cts_inst:1
DC:CTB02Q,cts_inst,Y,
DEBUG: CTB02Q:CTB02Q:Y:no_gated_clk_cts_1/cts_inst/cts_inst:2

[download]
Any ideas as to why the recursive call doesnt work as expected. Am I doing something drastically wrong?

Thanks

Diarmuid

update (broquaint): changed <pre> to <code> tags and added formatting

In reply to recursion hell. by diarmuid

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