In reply to MICRO_91:
The BNF (syntax) does not allow
default as a select expression. You can accomplish what you want by writing:
x1: cross a_cp , b_cp
{
ignore_bins a0b0 = ! binsof( a_cp.a0 ) || ! binsof( b_cp.b0 ) ;
}
However, if you just want a small selection of a cross, it might be easier to define another coverpoint instead of using a cross.
x1: coverpoint a==0 && b ==0 {
bins a0b0 = { 1'b1 } ; // corrected to only catch "truth"
}