User guide

24-226
SystemVerilog Testbench Constructs
Similarly, cross bin, bin2 receives data whenever either bin
hicp1vals, of coverpoint cp1, receives data, or bin hicp2vals, of
cover point cp2, receives data. Cross bin, bin3 receives data if any
bin of cover point cp1, whose value range overlaps with the range
[0:1], receives data, and, for the same sample event occurrence, any
bin of cover point cp2, whose value range overlaps with the range
[0:3], also receives data. In this example, cross bin bin3 receives
data when bin lowcp1vals, of cover point cp1, receives data, and
bin lowcp2vals, of cover point cp2, also receives data.
If none of the user-defined cross bins match, then VCS automatically
creates an auto cross bin to store the hit count for each unique
combination of the cover point bins.
Cumulative and Instance-based Coverage
Coverage statistics can be gathered both cumulatively and on a per-instance
basis.
Cumulative Coverage
Cumulative implies that coverage statistics (that is, bin hit counts and
coverage numbers) are computed for the covergroup definition. In this case
all instances of the covergroup contribute to a single set of statistics
maintained for the covergroup definition. By default, VCS computes
cumulative coverage information.
An example of when this kind of coverage is useful is when covering a
packet class. Cumulative coverage will provide information for all the
packet instances of the class.