CROSS Coverage

Coverage
, , ,
1 
int var;
int var_a,var_b,var_c;



coverpoint a : var_a
{
bins a_1 = {0};
bins a_2 = {1};
}

coverpoint b : var_b
{
bins b_1 = {0};
bins b_2 = {1};
}

coverpoint c : var_c
{
bins c_1 = {0};
bins c_2 = {1};
}
cross_all_cfg : cross a, cross b, cross c
{
ignore_bins invalid = binsof (a) iff (var =0);
}

Result : if i am doing it like this it shows only invalid bin in covergroup and not showing other bits of b and c in gui.
MY_EXPECTATION : i was expecting it will cross all bins a, b ,c only if (var=0) it will ignore bin of a

2

In reply to Himanshu m soni:

Lots of syntax errors in your code, but perhaps this is what you are looking for:

  int wvar;
  int var_a,var_b,var_c;
   
  covergroup cg;
    a : coverpoint var_a
    {
      bins a_1 = {0};
      bins a_2 = {1};
    }
    b : coverpoint var_b
    {
      bins b_1 = {0};
      bins b_2 = {1};
    }
    c : coverpoint var_c
    {
      bins c_1 = {0};
      bins c_2 = {1};
    }
     all_cfg: cross a, b, c
    {
      ignore_bins invalid = binsof (a) with (wvar==0);
     }
  endgroup

The iff keyword only disables sampling of existing bins, it does not eliminate them.

3

In reply to dave_59:

Thanks Dave,
I am grtting this error while using following piece of code
all_cfg: cross a, b, c
{
ignore_bins invalid = binsof (a) with (wvar==0);
}
The ‘with’ clause specified on the cross bin does not have any impact and is
invalid; it should contain at least one occurence of the constituent
coverpoint names.
Please remove or correct the clause and compile

Could you please help me in that ?

4

In reply to Himanshu m soni:

There is no such restriction in the LRM. I did have to make one small change to get it to compile on 3 out of 4 simulators on EDAPlayground. That was to make the variable used in the with clause an argument to the covergroup.

 int wvar;
  int var_a,var_b,var_c;
 
  covergroup cg(int v;
    a : coverpoint var_a
    {
      bins a_1 = {0};
      bins a_2 = {1};
    }
    b : coverpoint var_b
    {
      bins b_1 = {0};
      bins b_2 = {1};
    }
    c : coverpoint var_c
    {
      bins c_1 = {0};
      bins c_2 = {1};
    }
     all_cfg: cross a, b, c
    {
      ignore_bins invalid = binsof (a) with (v==0);
     }
  endgroup