Specman e coverage: ignored values appear in the coverage statistics

Question

I need to collect a coverage only when one of the items has a specific value (only when size == BYTE). The code I wrote:

item size           : size_t       = trans.size using no_collect;
item byte_alignment : uint(bits:2) = trans.addr using no_collect;

cross size, byte_alignment using ignore = (size != BYTE);

In the test I run, size != BYTE, but I still have the cross_size__byte_alignment item in the coverage statistics with zero Overall Average Grade.. Why?

How to prevent collecting coverage for size != BYTE?

Thank you for your help

Answer 1

use the "when" option on the item/cross to say when you want to collect coverage. use the "ignore" option to remove buckets from the item/cross.

if you want to collect only when size equals BYTE and you do not want to see the buckets where size is not BYTE, combine both options:

cross size, byte_alignment using ignore = (size != BYTE), when = (size == BYTE);