Divide by X

Source – SV Verification Directory

Problem Statement

Create a constraint to generate an N-bit random number that is divisible by a given natural number X. The value of X is parameterized, allowing it to be easily changed for different test scenarios.

Problem Breakdown

The key idea is to ensure that the random number generated satisfies the condition below:

\begin{equation} \label{eq.1} NUM \quad \% \quad X == 0 \end{equation}

The modulus operator (%) plays a key role in checking divisibility. To ensure a number is divisible by X, the remainder when dividing the number (NUM) by X must be zero.

Implementation

class cstrs_challenge #(int X = 5, N = 4);

   // class properties
   rand bit [N:0] y;

   constraint c {
      y % X == 0;
   }

   // display function
   function void disp();
      $display("Rand Num = %d", y);
   endfunction // disp

endclass // cstrs_challenge