Array of cover points in a covergroup

Question

covergroup spctl_hf_intg_cg @(posedge clk);
coverpoint `SPCTL_HF_INTG_INST.u_intg.g_regs[0].u_raw_edgedt.sig {
bins b[] = {1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 67108864, 134217728, 268435456, 536870912, 1073741824};
}
.............< many other cover points>
endgroup

I want to write array of cover points using for loop..

Please suggest a way to write in simple terms

Answer 1

kvenkatv

Forum Access

8 posts

March 08, 2016 at 12:14 pm

coverpoint `SPCTL_HF_INTG_INST.u_intg.g_regs[0].u_raw_edgedt.sig {
bins b[] = {1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 67108864, 134217728, 268435456, 536870912, 1073741824};
}
coverpoint `SPCTL_HF_INTG_INST.u_intg.g_regs[1].u_raw_edgedt.sig {
bins b[] = {1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 67108864, 134217728, 268435456, 536870912, 1073741824};
}
coverpoint `SPCTL_HF_INTG_INST.u_intg.g_regs[2].u_raw_edgedt.sig {
bins b[] = {1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 67108864, 134217728, 268435456, 536870912, 1073741824};
}
...... many more ...
writing manually all coverpoints doesn't seem easy, want to write in simple and concise terms

Answer 2

dave_59

Forum Moderator

11469 posts

March 08, 2016 at 3:21 pm

In reply to kvenkatv: See this link for an easier way to generate the bin/bit encodings.

You cannot create an array of coverpoints each with a different sample array element. What you can do is create an array of covergroup instances each referencing a different array element. If g_regs is a generate block array, you will have to construct each covergroup instance in that generate block, or a seperate generate-for-loop block.

— Dave Rich, Verification Architect, Siemens EDA

Answer 3

kvenkatv

Forum Access

8 posts

March 08, 2016 at 4:52 pm

Please post an example code

Answer 4

dave_59

Forum Moderator

11469 posts

March 08, 2016 at 5:37 pm

In reply to kvenkatv:
This should get you started

package global_types;
   typedef bit [31:0] uint;
   typedef uint uint_da[];
endpackage
module bot;
   import global_types::*;
   uint sig;
endmodule
module top;
   import global_types::*;
   bit clk;
 
   uint_da encodings = onehots();
   function uint_da onehots;
      onehots = new[32];
      foreach (onehots[i]) onehots[i] = 32'b1 << i;
   endfunction : onehots
   covergroup cg(ref uint arg)  @(posedge clk);
      option.per_instance = 1;
      coverpoint arg {
	 bins b[] = encodings;
      }
   endgroup : cg
 
  genvar i;
   for (i = 0; i<32;i++) begin : g_regs
      bot u();
   end
   for (i = 0; i<32;i++) begin
      cg cg_inst;
      initial cg_inst = new(g_regs[i].u.sig);
end
endmodule : top

— Dave Rich, Verification Architect, Siemens EDA

Answer 5

Sosale

Full Access

1 post

April 12, 2016 at 11:53 pm

In reply to dave_59:

Can anyone explain the need/application of this type of coverpoint array?

Answer 6

sunils

Full Access

106 posts

April 13, 2016 at 3:54 am

In reply to dave_59:

Hello Dave,

Can you please guide me to know is it possible to write like

covergroup cg(ref bit [3:0]hello.bye); 
 
   coverpoint hello.bye{
    bins a ...;
    bins b ...;
    ...
    ...
}

I mean to say can we use hierarchical reference in covergroup definition where array of covergroup is implemented. Please guide.

Regards
Sunils

Regards,
Sunil

Answer 7

dave_59

Forum Moderator

11469 posts

April 13, 2016 at 6:57 am

In reply to sunils:
You can never use a "." when declaring the name of an identifier. In this case, you are declaring the name of an argument to a covergroup constructor.

— Dave Rich, Verification Architect, Siemens EDA

Answer 8

dave_59

Forum Moderator

11469 posts

April 13, 2016 at 6:58 am

In reply to Sosale:

In this case, an array of covergroups is needed to cover signals in an array of instances.

— Dave Rich, Verification Architect, Siemens EDA

Answer 9

sunils

Full Access

106 posts

April 14, 2016 at 4:09 am

In reply to dave_59:o

Hello Dave,

Thanks for the reply. I need to cover the variables which are defined in packet class. Now how to cover these packet class variable in coverage model class without using the dot operator(Hierarchical reference). Alongwith, these are all unpacked array variabels defined in packet class. Please guide.

Regards
Sunil.

Regards,
Sunil

Answer 10

dave_59

Forum Moderator

11469 posts

April 14, 2016 at 6:50 am

In reply to sunils:

You just need to pass each element of the array into the covergroup

covergroup cg(ref bit [3:0] bye); 
  coverpoint bye;
...
endgroup

foreach (hello.bye[i]) cg_inst[i] = new (hello.bye[i]);

— Dave Rich, Verification Architect, Siemens EDA

Answer 11

prang

Full Access

14 posts

July 10, 2018 at 4:15 pm

In reply to dave_59:

Quote:

In reply to kvenkatv:
This should get you started

package global_types;
   typedef bit [31:0] uint;
   typedef uint uint_da[];
endpackage
module bot;
   import global_types::*;
   uint sig;
endmodule
module top;
   import global_types::*;
   bit clk;
 
   uint_da encodings = onehots();
   function uint_da onehots;
      onehots = new[32];
      foreach (onehots[i]) onehots[i] = 32'b1 << i;
   endfunction : onehots
   covergroup cg(ref uint arg)  @(posedge clk);
      option.per_instance = 1;
      coverpoint arg {
	 bins b[] = encodings;
      }
   endgroup : cg
 
  genvar i;
   for (i = 0; i<32;i++) begin : g_regs
      bot u();
   end
   for (i = 0; i<32;i++) begin
      cg cg_inst;
      initial cg_inst = new(g_regs[i].u.sig);
end
endmodule : top

Just wanted to clarify should it be cg_inst[32] instead of cg_inst?

...
  cg cg_inst[32];
  genvar i;
   for (i = 0; i<32;i++) begin : g_regs
      bot u();
   end
   for (i = 0; i<32;i++) begin
      initial cg_inst[i] = new(g_regs[i].u.sig);

Answer 12

sundarji

Forum Access

4 posts

July 14, 2021 at 2:05 am

In reply to dave_59:

Could you able to help me with genvar? With usage and purpose??

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