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Randomize

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Overview

In Verilog, randomization refers to the process of generating random or pseudo-random values for variables or signals during simulation. Randomization is used to create various test scenarios, stimulate different input conditions, and uncover corner cases in a design's behavior. It's a crucial technique in functional verification to ensure that a design functions correctly across a wide range of possible inputs.

$random
$urandom
$random_range( min, max )

Theory Questions
Coding Questions 
    module top;

    reg [31:0] RAND;

    initial
    begin
        RAND = $urandom;
        RAND[0] = 1;
        
        $display("RAND : %0d", RAND);
    end

endmodule

    function getNum;
    return $urandom%100;    
endfunction

module top;

    reg [31:0] RAND;

    initial
    begin
        RAND = getNum();
        
        $display("RAND : %0d", RAND);
    end

endmodule

    function getMaxMinRange( integer max, integer min );
    return ($urandom%(max-min))+min+1;    
endfunction

module top;

    reg [31:0] RAND;

    initial
    begin
        RAND = getMaxMinRange(30,5);
        
        $display("RAND : %0d", RAND);
    end

endmodule

    function getRand;
    return ($urandom/3)*3;
endfunction

module top;

    reg [31:0] RAND;

    initial
    begin
        RAND = getRand();
        
        $display("RAND : %0d", RAND);
    end

endmodule

    module unique_digit_random;

  function integer dec_rand_num();
    integer number;
    integer i, digit, count;
    reg [3:0] used [0:9];      // To track if a digit is used

    i = 0;
    digit = 0;

    number = 0;
    count = 0;

    // Reset the used digits array
    for (i = 0; i < 10; i = i + 1)
      used[i] = 0;

    // Generate a random number with unique digits
    while (count < 6) begin // 6 digits
      digit = $urandom % 10; // Random digit between 0 and 9
      if (!used[digit]) begin
        used[digit] = 1;                // Mark digit as used
        number = number * 10 + digit;  // Append digit to the number
        count = count + 1;
      end
    end

    return number;
  endfunction

  initial begin
    repeat(10) begin
      $display("Number : %0d", dec_rand_num());
    end
  end
endmodule
    Locked Solution 
    function integer getWeight();
    return {$urandom,(($urandom%100)<20)?1'b0:1'b1};
endfunction

module top;

    integer RAND;
    integer i;

    initial
    begin
        for( i = 0; i < 20; i=i+1 )
        begin
            RAND = getWeight();
            $display("RAND : %0d", RAND);
        end
    end

endmodule

    function reg [31:0] getUs();
    return {$urandom>>1};
endfunction

module top;

    integer RAND;

    initial
    begin
        RAND = getUs();
        $display("RAND : %0d", RAND);
    end

endmodule
    Locked Solution 
    function reg [63:0] get64();
    return {$urandom,$urandom};
endfunction

module top;

    reg [63:0] RAND;

    initial
    begin
        RAND = getUs();
        $display("RAND : %0d", RAND);
    end

endmodule