Arrays - mbits-mirafra/verilator GitHub Wiki

Dynamic Array:

                                          
   // module declaration for dynamic array example
module dynamic_array;

// creating dynamic array of type int
  int abc [];

  initial begin
    // give size of dynamic array for eg. take 7
    $display("");
    $display("// setting array size to seven");
    abc = new[7];

    // initialize array elements with 7 values
    abc = '{11,12,13,14,15,16,17};

    // iterate through array and print values
    $display("");
    $display("// dynamic array values");
    foreach(abc[i])begin
      $display("value of abc[%0d]=%0d",i,abc[i]);
    end
    $display("");
  end
endmodule : dynamic_array

Output:

Associative array:

Error code:

// module declaration for associative array
module associative_method();

// Declare an associative array abc of type int and index type string
  int abc[string];
  string variable;
  string val1;

  initial begin
    $display("");
    $display("// associative array given below");
    // initialize each dynamic array with values
    abc = '{ "vadodara" : 10 , "ahmedabad" : 25 , "surendranagar" : 38 , "rajkot" : 55 ,
    "surat":48};

    // printing both array values
    $display("abc = %p",abc);

    // function num(): this function prints the number of items in array
    $display("");
    $display("// abc.num() - gives number of elements inside array");
    $display("// output of abc.num()");
    $display("%0d",abc.num());

    //function size(): this works same as num()
    $display("");
    $display("// abc.size() - returns size of array");
    $display("// output of abc.size()");
    $display("%0d",abc.size());

    // function exists(index): this function checks if the particular key exist in array or not
    $display("");
    $display("// abc.exists(index) - returns whether the particular index exists inside array or not");
    $display("// output of abc.exist(vadodara)");
    if(abc.exists ("vadodara")) begin
      $display("index vadodara exists in array");
    end
    else begin
      $display("index vadodara not exists in array");
    end

    // function first(variable): it will assign value of first index to variable
    $display("");
    $display("// abc.first(index) - returns the first index value in array");
    $display("// output of abc.first(variable)");
    if(abc.first(variable)) begin
      $display("abc[%s]=%0d",variable,abc[variable]);
    end

    // function last(variable): it will assign value of last index to variable
    $display("");
    $display("// abc.last(index) - returns the last index value in array");
    $display("// output of abc.last(variable)");
    if(abc.last(variable)) begin
      $display("abc[%s]=%0d",variable,abc[variable]);
    end

    // function next(index): it will give next index value which is greater than current index the 
    // in array
    $display("");
    $display("// abc.next(index) - gives next index value which is greater than current index"); 
    $display("// and it's corresponding value in array");
    $display("// output after abc.next(val1)");
    if(abc.next(val1)) begin
      $display("abc[%s]=%0d",val1,abc[val1]);
    end
    
    // function delete(index): it will delete index from the array
    $display("");
    $display("// abc.delete(index) - deletes the index and it's corresponding value in array");
    $display("// output after deleting surendranagar index in array");
    abc.delete("surendranagar");
    $display("%p",abc);
    $display("");
  end

endmodule : associative_method

On running the above code we get the errors as methods of associative array returns int type which is 32 bit whereas “if” condition expects 1 bit, verilator does not support truncating and appending additional bits when there is a change in data size.

This error can be cleared by performing static casting to bit within the logical operator “if”. i.e., if(bit'(abc.exists ("vadodara")))

Error:

Without error code:

// module declaration for associative array
module associative_method();

// Declare an associative array abc of type int and index type string
  int abc[string];
  string variable;
  string val1;

  initial begin
    $display("");
    $display("// associative array given below");
    // initialize each dynamic array with values
    abc = '{ "vadodara" : 10 , "ahmedabad" : 25 , "surendranagar" : 38 , "rajkot" : 55 ,
    "surat":48};

    // printing both array values
    $display("abc = %p",abc);

    // function num(): this function prints the number of items in array
    $display("");
    $display("// abc.num() - gives number of elements inside array");
    $display("// output of abc.num()");
    $display("%0d",abc.num());

    //function size(): this works same as num()
    $display("");
    $display("// abc.size() - returns size of array");
    $display("// output of abc.size()");
    $display("%0d",abc.size());

    // function exists(index): this function checks if the particular key exist in array or not
    $display("");
    $display("// abc.exists(index) - returns whether the particular index exists inside array or not");
    $display("// output of abc.exist(vadodara)");
    if(bit'(abc.exists ("vadodara"))) begin
      $display("index vadodara exists in array");
    end
    else begin
      $display("index vadodara not exists in array");
    end

    // function first(variable): it will assign value of first index to variable
    $display("");
    $display("// abc.first(index) - returns the first index value in array");
    $display("// output of abc.first(variable)");
    if(bit'(abc.first(variable))) begin
      $display("abc[%s]=%0d",variable,abc[variable]);
    end

    // function last(variable): it will assign value of last index to variable
    $display("");
    $display("// abc.last(index) - returns the last index value in array");
    $display("// output of abc.last(variable)");
    if(bit'(abc.last(variable))) begin
      $display("abc[%s]=%0d",variable,abc[variable]);
    end

    // function next(index): it will give next index value which is greater than current index the 
    // in array
    $display("");
    $display("// abc.next(index) - gives next index value which is greater than current index"); 
    $display("// and it's corresponding value in array");
    $display("// output after abc.next(val1)");
    if(bit'(abc.next(val1))) begin
      $display("abc[%s]=%0d",val1,abc[val1]);
    end
    
    // function delete(index): it will delete index from the array
    $display("");
    $display("// abc.delete(index) - deletes the index and it's corresponding value in array");
    $display("// output after deleting surendranagar index in array");
    abc.delete("surendranagar");
    $display("%p",abc);
    $display("");
  end

endmodule : associative_method

Output:

Queue:

module queue_data;

string queue1[$];
//int queue2[$];

initial 
begin
  queue1 = {"manipal", "banglaore", "udupi"};

  $display("\nqueue1 = ['manipal', 'banglaore', 'udupi']");

  $display("\n OUTPUT : ");

  //queue1.pop_front();
  $display("\n // pop_front()-pop front the array element at first index position of queue1: \n\t %p",queue1.pop_front());
  $display("\n // After pop front  the 'manipal' is removed from queue1 is : \n\t %p", queue1);
  //queue1.pop_back();
  $display("\n // pop_back()-pop back the array element at last index position of queue1: \n\t %p", queue1.pop_back());
  $display("\n // After pop back the 'udupi' is removed from queue1 is :\n\t %p", queue1);

  queue1.push_front("Yelahanka");
  $display("\n // push front the array element at first index position of queue1:");
  $display(" // push_front()-After push front the elements of the  queue1 is :\n\t %p", queue1);

  queue1.push_back("udupi");
  $display("\n // push back the array element at last index position of queue1:");
  $display(" // push_back()-After push back the elements of the queue1 is :\n\t %p", queue1);
  $display("");
end 
endmodule:queue_data

Output: