Randomization error on dynamic array

SystemVerilog
1 
constraint c_mult_hdr
  {
        if(gen_mult_audio_hdrs)
        {
                foreach(data_len_q[i])
                {
                        data_len_q[i] >0;
                }
                **//num_of_ado_hdrs == 2;**
                data_len_q.size() == num_of_ado_hdrs;
                len-3 == (num_of_ado_hdrs * ado_hdr_size ) + data_len_q.sum() + ado_cksum_size;
                len inside  { [9:12]   };  //6 is minimum =(3ucom hdr) -2 (aud hdr+chksum) = 1 (data waord)
                solve num_of_ado_hdrs before data_len_q.size;
        }
  }

Hi, I have the above constraint if i dont have the line in bold where i set the num… ==2, i get an randomization error saying illegal attempt to resize dynamic array.

** Error: (vsim-7020) Illegal attempt to resize random dynamic array ‘data_len_q’ to 1554575876 elements. (SolveArrayResizeMax=10000)

Any idea what i am doing wrong?

2

In reply to CRVAddict:

I have lots of ideas. But please show the declarations of all variables used in your constraints, and maybe I can give you one of them.

3

In reply to dave_59:

Here it is,

int gen_mult_audio_hdrs;
int ado_hdr_size=1; //1hdr
int ado_cksum_size=1; //1hdr
rand int unsigned num_of_ado_hdrs;
rand int unsigned data_len_q[$];
rand bit[7:0] rec_type;

4

In reply to CRVAddict:

Your can use solve size before randomize element

If you don’t have randomized order, it might randomize element before size.

Second solution is that you can have a pre-random function.

5

In reply to kangrh007:

I do have that already right?

solve num_of_ado_hdrs before data_len_q.size;

6

In reply to CRVAddict:

Yes. But it is inside the if statement. Move it out, or use a new constraint block, then it should work

7

In reply to CRVAddict:

The solve before construct is unnecessary here because there is an implicit ordering when sizing a dynamic array.

The issue here is you need to limit the values to prevent overflow. See http://go.mentor.com/verilog-in-constraints

8

In reply to dave_59:

the max value of len is contained to be 12.

(num_of_ado_hdrs * 1 ) + data_len_q.sum() + 1;

so num_of_ado_hdrs + data_lenq.sum == 7 so that i thought that would act as a constraint.

how can data_len_q has more than 10k element and meet the value of 7 when the int’s are unsigned

9

In reply to CRVAddict:

Making a variable unsigned does not prevent overflow.

(32'hFFFFFFFD + 32'f0000000A) == 32'd7