Reporting on Std_Logic_Vector

In my blog post VHDL Reporting an integer I developed some VHDL to print out a list of number from index of a FOR LOOP. The following VHDL expands this idea and looks at how to print out a number of Std_Logic_Vectors defined in as a constant.


library ieee;
use ieee.std_logic_1164.all;

entity testxx is
end entity;

architecture arch of testxx is

--The function to_string was taken from 
--http://www-ee.uta.edu/Online/Zhu/spring_2007/tutorial/how_to_print_objexts.txt
  function to_string(sv: Std_Logic_Vector) return string is
    use Std.TextIO.all;
    variable bv: bit_vector(sv'range) := to_bitvector(sv);
    variable lp: line;
  begin
    write(lp, bv);
    return lp.all;
  end;
  
  type tvector is array (7 downto 0) 
              of std_logic_vector(3 downto 0);

  constant test_vectors: tvector := ("0000", 
                                     "0011", 
                                     "0101", 
                                     "0111", 
                                     "1001", 
                                     "1010", 
                                     "1100",
                                     "1111");

  begin
  
  process
    begin
       for i in 7 downto 0 loop
        report "loop_i=" & integer'image(i);
        report "length=" 
               & integer'image(test_vectors(i)'length);
        report "vector=" & to_string(test_vectors(i));
        wait for 10 ns;
       end loop;
      wait;
  end process;
    
end architecture;

The output from modelsim is as follows:


# ** Note: loop_i=7
#    Time: 0 ps  Iteration: 0  Instance: /testxx
# ** Note: length=4
#    Time: 0 ps  Iteration: 0  Instance: /testxx
# ** Note: vector=0000
#    Time: 0 ps  Iteration: 0  Instance: /testxx
# ** Note: loop_i=6
#    Time: 10 ns  Iteration: 0  Instance: /testxx
# ** Note: length=4
#    Time: 10 ns  Iteration: 0  Instance: /testxx
# ** Note: vector=0011
#    Time: 10 ns  Iteration: 0  Instance: /testxx
# ** Note: loop_i=5
#    Time: 20 ns  Iteration: 0  Instance: /testxx
# ** Note: length=4
#    Time: 20 ns  Iteration: 0  Instance: /testxx
# ** Note: vector=0101
#    Time: 20 ns  Iteration: 0  Instance: /testxx
# ** Note: loop_i=4
#    Time: 30 ns  Iteration: 0  Instance: /testxx
# ** Note: length=4
#    Time: 30 ns  Iteration: 0  Instance: /testxx
# ** Note: vector=0111
#    Time: 30 ns  Iteration: 0  Instance: /testxx
# ** Note: loop_i=3
#    Time: 40 ns  Iteration: 0  Instance: /testxx
# ** Note: length=4
#    Time: 40 ns  Iteration: 0  Instance: /testxx
# ** Note: vector=1001
#    Time: 40 ns  Iteration: 0  Instance: /testxx
# ** Note: loop_i=2
#    Time: 50 ns  Iteration: 0  Instance: /testxx
# ** Note: length=4
#    Time: 50 ns  Iteration: 0  Instance: /testxx
# ** Note: vector=1010
#    Time: 50 ns  Iteration: 0  Instance: /testxx
# ** Note: loop_i=1
#    Time: 60 ns  Iteration: 0  Instance: /testxx
# ** Note: length=4
#    Time: 60 ns  Iteration: 0  Instance: /testxx
# ** Note: vector=1100
#    Time: 60 ns  Iteration: 0  Instance: /testxx
# ** Note: loop_i=0
#    Time: 70 ns  Iteration: 0  Instance: /testxx
# ** Note: length=4
#    Time: 70 ns  Iteration: 0  Instance: /testxx
# ** Note: vector=1111
#    Time: 70 ns  Iteration: 0  Instance: /testxx