Having problem with FOR LOOP which leads to endless loop in system verilog

SystemVerilog
1

I’m having some problems with for-loop statement in system verilog.

module tb_top();
  int num_q[$]  = '{0,1,2,3,4,5,6,7,8,9,10};
  int del_q[$]  = '{1,2};
   
  initial
    begin
      $display("num_q_size=%0d",num_q.size());
      
      for(int ii = num_q.size(); ii >= 'd0; ii--)begin
        $display("Loop count=%0d",ii);
        if(num_q[ii-1] inside del_q)
          num_q.delete(ii-1);
        else 
          continue;
      end  

      $display("value of num_q=%p",num_q);
    end  
endmodule

The above code runs repeatedly without no hope of stopping.

I don’t understand the reason. Can some one please explain

2

In reply to deepak_sadasivam_uvm:


add extra indx ques , loop through it to delete the index.
module tb_top();
int num_q[$] = '{0,1,2,3,4,5,6,7,8,9,10};
int del_q[$] = '{1,2};
int idx[$]; // index queue 
initial
begin
$display("num_q_size=%0d",num_q.size());
 
  foreach(del_q[i]) begin 
    idx = num_q.find_index with (item == del_q[i]);     
    if(idx.size != 0 ) begin
    foreach(idx[i]) begin // loop through index value. 
      num_q.delete(idx[i]); // delete the index
    end 
    end 
  end 
  $display("value of num_q=%p",num_q);
end
endmodule
3

In reply to kddholak:

Hi,

Thanks for answering but my question is more understand the below code:

Working code:

for(int ii = num_q.size(); ii > 'd0; ii--)begin
  $display("Loop count=%0d",ii);
  if(num_q[ii-1] inside del_q)
    num_q.delete(ii-1);
  else
   continue;
end

Code which goes to infinite loop:

for(int ii = num_q.size(); ii >= 'd0; ii--)begin
  $display("Loop count=%0d",ii);
  if(num_q[ii-1] inside del_q)
    num_q.delete(ii-1);
  else
   continue;
end

can you help here what going wrong.

4

In reply to deepak_sadasivam_uvm:


for(int ii = num_q.size(); ii >= 0; ii--)begin - remove 'd it will work
Issue is 'd0 - It is treating as unsigned integer 32'd0
ii will become 32'hffff_ffff after 0 and it is greater than 0
5

In reply to kddholak:

In reply to deepak_sadasivam_uvm:


add extra indx ques , loop through it to delete the index.
module tb_top();
int num_q[$] = '{0,1,2,3,4,5,6,7,8,9,10};
int del_q[$] = '{1,2};
int idx[$]; // index queue 
initial
begin
$display("num_q_size=%0d",num_q.size());
foreach(del_q[i]) begin 
idx = num_q.find_index with (item == del_q[i]);     
if(idx.size != 0 ) begin
foreach(idx[i]) begin // loop through index value. 
num_q.delete(idx[i]); // delete the index
end 
end 
end 
$display("value of num_q=%p",num_q);
end
endmodule

Yes you provided the solution thanks for that, but what’s the issue? I think addressing the issue is more benficial than providing solution.