Cross Auto Bin Max

Hello friend,
In this blog we are going to discuss about the cross auto bin max.

ex.
bit [3:0] a;
bit [3:0] b;

A_C : coverpoint a_c
{
   bin1 = bins[7:0];
   bin2 = bins[7:15];
 }

B_C : coverpoint b_c
{
   bin1 = bins[7:0];
   bin2 = bins[7:15];
 }

i)  A_B_CROSS : cross a_c , b_c;
ii) A_B_CROSS : cross a , b;

In first case we are doing cross coverage of to coverpoints where in second case two variables.
In first case four cross bins will be generated as each cover point is having two two bins where in second case (2^4 * 2^4) = 256 bins will be generated.

This happens because for simple coverage auto_bin_max value is 64 where cross_auto_bin_max is infinite for cross coverage.

So say if you have declared two vars as int and then you are directly performing their cross coverage then (2^32 * 2^32) bins will be generated because cross_auto_bin_max value is infinite. If you are just performing simple coverage for one of the var which is declared as int and if you are not passing any explicit bins then only 64 bins will be generated because auto_bin_max value is 64.

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