By default, Vera only matches a tran bin definition that uses an x if the coverage point has an x in that bit position (the semantics are similar to the === operator). You can use the wildcard tran bin definitions to make Vera consider an x in the bin definition as a wildcard.

  1 class coverage_wildcard_tran {
  2   bit [3:0] value;
  3   event     now;
  4 
  5   coverage_group something {
  6      sample_event = sync(ALL,now);
  7      sample value {
  8       wildcard trans ABC_0 (4'b00xx -> 4'bxx00);
  9      }
 10   }
 11 
 12   task update_coverage (bit [3:0] value) {
 13      this.value = value;
 14      trigger(now);
 15   }
 16 }
 17 
 18 
 19 
 20 program test {
 21   coverage_wildcard_tran cov = new();
 22   bit [3:0] v; 
 23   repeat (10) {
 24     v = urandom__range(14,0);
 25     printf("Value is %d\n",v);
 26     cov.update_coverage(v);
 27     delay(1);
 28   }
 29 }    

 Value is 13
 Value is 14
 Value is  4
 Value is  4
 Value is  2
 Value is  8
 Value is  6
 Value is  7
 Value is  6
 Value is  2

 Group : test::coverage_wildcard_tran::something
 
 ====================================================
 Group : test::coverage_wildcard_tran::something
 ====================================================
 Score   Weight  Goal    
 100.00  1       100     
 
 
 
 
 ====================================================
 
 Samples for Group : test::coverage_wildcard_tran::something
 
 
 
 Variable Expected Covered Percent Goal Weight 
                                               
 Total    1        1       100.00              
                                               
 value    1        1       100.00  100  1      
                                               
 
 
 ====================================================
 
 Summary for variable value
 
 
                   Expected Covered Percent 
                                            
 User Defined Bins 1        1       100.00  
                                            
 
 
 User Defined Bins for value
 
 
 Bins
 
 name  count at least  
                      
 ABC_0 1     1        
                      
 
 

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