systemverilog 枚举类型

1.定义枚举类型

  enum          {RED, YELLOW, GREEN}         light_1;         // int type; RED = 0, YELLOW = 1, GREEN = 2
  enum bit[1:0] {RED, YELLOW, GREEN}         light_2;         // bit type; RED = 0, YELLOW = 1, GREEN = 2

2.定义枚举变量

module tb;
  // "e_true_false" is a new data-type with two valid values: TRUE and FALSE
  typedef enum {TRUE, FALSE} e_true_false;       
 
  initial begin
    // Declare a variable of type "e_true_false" that can store TRUE or FALSE
    e_true_false  answer;                       
 
    // Assign TRUE/FALSE to the enumerated variable
    answer = TRUE;
 
    // Display string value of the variable
    $display ("answer = %s", answer.name);
  end
endmodule

3.枚举变量的方法：

// GREEN = 0, YELLOW = 1, RED = 2, BLUE = 3
typedef enum {GREEN, YELLOW, RED, BLUE} colors;
 
module tb;
  initial begin
      colors color;
 
      // Assign current value of color to YELLOW
      color = YELLOW;
 
      $display ("color.first() = %0d", color.first());  // First value is GREEN = 0
      $display ("color.last()  = %0d", color.last());  // Last value is BLUE = 3
      $display ("color.next()  = %0d", color.next());   // Next value is RED = 2
      $display ("color.prev()  = %0d", color.prev());   // Previous value is GREEN = 0
      $display ("color.num()   = %0d", color.num());   // Total number of enum = 4
      $display ("color.name()  = %s" , color.name());   // Name of the current enum
    end
endmodule