How can I use hex value into enum?

SystemVerilog
,
1

Hi,

I’m trying to implement a hex valurs into enum as below.


module enum_datatype;
 
  //declaration
  //enum reg[7:0] { red=0x1, green, blue=4, yellow, white=10, black } Colors;
  typedef enum reg[7:0] { red=8'h2, green, blue=4, yellow, white=10, black } Colors;
  
  //display members of Colors
  initial begin
    Colors = Colors.first;
    for(int i=0;i<$size(Colors);i++) begin
      $display("Colors :: Value of  %0s \t is = %0d and Size is %d",Colors.name,Colors, $size(Colors));
      Colors = Colors.next;      
    end
  end
  
endmodule

but I’ve got a hierarchical reference error.
How can I use hex value into enum?

This is C code, how do I get a equivalent systemverilog code?


#include <stdio.h> 
enum index { A = 0xa3, B = 0x07, C = 0x18 }; 
int main() 
{ 	
index i[] = { A, B, C }; 
 	
for (int j = 0; j < 3; j++) 		
printf("%X ", i[j]); }
2

In reply to UVM_LOVE:

module enum_datatype;
 
  //declaration
  //enum reg[7:0] { red=0x1, green, blue=4, yellow, white=10, black } Colors;
  typedef enum reg[7:0] { red=8'h2, green, blue=8'h4, yellow, white=8'h10, black } Colors;
  Colors Color;
  
  //display members of Colors
  initial begin
    Color = Color.first;
    for(int i=0;i<$size(Colors);i++) begin
      $display("Colors :: Value of  %0s \t is = %0d and Size is %d",Color.name,Color, $size(Color));
      Color = Color.next;      
    end
  end
  
endmodule

Colors is a datatype, declared a variable name Color. This works now!

3

In reply to yourcheers:

Also, instead of “$size”, you should use “Color.num()”, to iterate over the number of elements

4

In reply to yourcheers:

$size(colors) gives you the number of array elements, 8, which is the same as $bits(Colors) in this case. Colors.num gives the number of enumerations.

You could also use a do-while loop

module enum_datatype;
  typedef enum bit[7:0] { red=8'h2, green, blue=8'h4, yellow, white=8'h10, black } Colors;
   Colors Color;
   
   //display members of Colors
   initial begin
      Color = Color.first;
      do begin
	 $display("Colors :: Value of  %0s \t is = %0d and Size is %d",Color.name,Color, $bits(Color));
	 Color = Color.next;      
      end while(Color != Color.first);
  end
endmodule
5

In reply to dave_59:

In reply to yourcheers:
$size(colors) gives you the number of array elements, 8, which is the same as $bits(Colors) in this case. Colors.num gives the number of enumerations.
You could also use a do-while loop

module enum_datatype;
typedef enum bit[7:0] { red=8'h2, green, blue=8'h4, yellow, white=8'h10, black } Colors;
Colors Color;
//display members of Colors
initial begin
Color = Color.first;
do begin
$display("Colors :: Value of  %0s \t is = %0d and Size is %d",Color.name,Color, $bits(Color));
Color = Color.next;      
end while(Color != Color.first);
end
endmodule

Sir,

Is there a way to use same enumeration value?
because I’d like to add to enum as
typedef enum reg[7:0] { a=10, b=10, c=10} like this one.

I encounters an error message as each enumeration constance must have a unique value.
What am I supposed to do?

6

In reply to UVM_LOVE:

I think you have hit the XY Problem.

Please explain what you are looking to accomplish without involving an enum.

7

In reply to dave_59:

In reply to UVM_LOVE:
I think you have hit the XY Problem.
Please explain what you are looking to accomplish without involving an enum.

Sir, I’m trying to find what I want it while resolving.

Actually, I didn’t realize that enum need to be as a unique value
in C language, we can use the same enum value used in C code as the below.

include <stdio.h>
enum index { A = 0xa3, B = 0x18, C = 0x18 };
int main() {
index i = { A, B, C };
for (int j = 0; j < 3; j++)
printf("%X ", i[j]);
}
but can’t in systemverilog. so I’m trying to find a way.

8

In reply to UVM_LOVE:

From LRM:
Section 6.19 Enumerations
Both the enumeration names and their integer values shall be unique. It shall be an error to set two values to the same name or to set the same value to two names, regardless of whether the values are set explicitly or by automatic incrementing.

9

In reply to UVM_LOVE:

You could do

module top;
parameter A = 'ha3, B = 'h18, C = 'h18;
int i[] = { A, B, C };  
initial foreach(i[j]) $display("%h ", i[j]); 
endmodule

or you could do

module top;
int i[string] = '{ "A":'ha3, "B":'h18, "C":'h18 };  
initial foreach(i[j]) $display("%h ", i[j]); 
endmodule