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How to write to console a custom array type

I am fairly new to VHDL and I am running some snippets from a code I was given to see what it is doing. There is a custom array type I want to see in the console, but I get and error when I try to write it.

entity hello_world is 
end entity hello_world;

library STD;                          
library IEEE;                        
use IEEE.std_logic_1164.all;           
use STD.textio.all;                  
use IEEE.std_logic_textio.all;         
use IEEE.numeric_std.all;                                    

architecture test of hello_world is 

    type row_type is array(0 to 2)  of std_logic_vector(3 downto 0);
    type new_type is array(0 to 1)  of row_type;
    signal  max_new : new_type := (others => (others => (others => '0')));

    begin
    my_print :  process is                  
        variable my_line : line;    
        begin
            write(my_line, string'("Value of max_new"));      
            write(my_line, max_new);    
            writeline(output, my_line);            
            wait;
    end process my_print;
end architecture test;

The error I get while running the simulation is:
Error: type error near 'max_new': expected type 'std_ulogic'. Error: formal 'l' of mode inout must have an associated actual. Error: formal 'value' has no actual or default value. Error: indexed name prefix type 'void' is not an array type enter image description here

If I understood correctly, row type is an array of size 3, in each position I have a vector made of 4 bits. new_type is an array of size 2, in each position I have a row_type, which is an array of size 3 with a 4 bits vector in each position. Is this correct? Since it is initialized to 0, I expect to see only that.

I am using Vivado 2018.3 for the simulation.

Any help would be highly appreciated!

Solution

  • The function write of std.textio can take the following arguments as value (https://www.hdlworks.com/hdl_corner/vhdl_ref/VHDLContents/TEXTIOPackage.htm) :

    • bit
    • bit_vector
    • boolean
    • character
    • integer
    • real
    • string
    • time

    IEEE.std_logic_textio add std_logic and his derivated to this list but Array is not handled by write.

    You can print your array like that :

    my_print :  process is                  
  variable my_line : line;    
begin
  write(my_line, string'("Value of max_new"));
  for I in 0 to 1 loop
    for J in 0 to 2 loop 
      write(my_line, max_new(I)(J));
    end loop;
  end loop;    
  writeline(output, my_line);            
  wait;
end process my_print;