Constraint for random dynamic value

UVM
,
1

Hi,

I want to make dynamic random value in constraint as below.
Please help me.


rand int busy_bit[];
rand int count;

// When I count busy_bit[] = 1, the number of sum should be equal to count.
// The expression could be
// foreach (busy_bit[i])
//   sum += busy_bit[i]
// My goal is "sum == count"

constraint busy_bit_count{
......// How to express above condition in the constraint.....
}
2

In reply to uvmbee:

You’ve considered a dynamic array. You should assign a range of sizes to the dynamic array or the required size. Then, you can use:


constraint c1 {busy_bit.sum == count} //to set the sum of elements in the array = count
constraint c2 {busy_bit.size inside {[25:50]};} //user needs the size of the array to be in the range 25-50 and the sum of elements in it should be equal to the value of count.

Hope it helped :)

3 


class busy_bit;
  
  rand int busy_bit[];
  rand int count;
  
  constraint ab {
  busy_bit.size == 5;
  foreach (busy_bit[i]) busy_bit[i] inside {[5:10]};
    busy_bit.sum() with (int'(item)) == count;  
  }
  
 
endclass
 
module test;
  busy_bit m1;
  initial begin
    m1=new();
    repeat (3) begin
    assert(m1.randomize());
    $display ("%p",m1.busy_bit);
    $display ("%d",m1.count);
    end end
endmodule