Functional Coverage Wildcard Bins Creation

SystemVerilog
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1

Hi All

I have a 26 bit signal which is formed by concentrating 3 signals like shown below , i want tranition coverage for the 26 bit number where
cc transitions to same number , nn and mm can transition to any number .

bit [11:0] cc;
bit [5:0] nn;
bit [7:0] mm;

rrr_cp : coverpoint {cc,nn,mm} {
   wildcard bins gg[] = (26'b101100110101xxxxxxxxxxxxxx => 26'b101100110101xxxxxxxxxxxxxx);
}

When i create bins like above using wildcard bins, i get the following error
“On Expansion results in more than 1 million bins per coverpoint”

Please help me how to create these bins.
Since i need transitions for all combinations , i will not be able to write them manually

2

In reply to donald:

But there are 228 combinations with what you specified. That’s not practical to collect coverage with dynamic simulation. You need to explain more what requirements you are trying to cover.

3

In reply to dave_59:

In reply to donald:
But there are 228 combinations with what you specified. That’s not practical to collect coverage with dynamic simulation. You need to explain more what requirements you are trying to cover.

I do not want 2^28 transitions . I want MSB 12 bits to be same.
I wanted the following
bit [11:0] cc;
bit [5:0] nn;
bit [7:0] mm;

when cc does not transition , then i want all transtions of other 14 bits of nn and mm
example:
when (cc = 12’d100 => cc = 12’d100)
{nn,mm} should transition 2^14

4

In reply to donald:

Do you want to cover ALL transitions of 14 bits, or ANY transition of 14 bits?

5

In reply to dave_59:

In reply to donald:
Do you want to cover ALL transitions of 14 bits, or ANY transition of 14 bits?

We want to cover all transitions

6

In reply to donald:

Well, there are 228 possible transitions of 14 bits (minus the 214 transitions to the same state). Thats 268419072 possible transitions. You cannot expect to cover all transitions with a bin for each.