Multi-Dimensional Array Signals and Variables Coding Examples - 2024.1 English

Vivado Design Suite User Guide: Synthesis (UG901)

Document ID
UG901
Release Date
2024-05-30
Version
2024.1 English
  1. Make the following declarations:
    subtype WORD8 is STD_LOGIC_VECTOR (7 downto 0);
    type TAB05 is array (4 downto 0) of WORD8;
    type TAB03 is array (2 downto 0) of TAB05;
    signal WORD_A : WORD8;
    signal TAB_A, TAB_B : TAB05;
    signal TAB_C, TAB_D : TAB03;
    constant CNST_A : TAB03 := (
    ("00000000","01000001","01000010","10000011","00001100"),
    ("00100000","00100001","00101010","10100011","00101100"),
    ("01000010","01000010","01000100","01000111","01000100"));
    
  2. You can now specify:
    • A multi-dimensional array signal or variable:
      TAB_A <= TAB_B; TAB_C <= TAB_D; TAB_C <= CNST_A;
    • An index of one array:
      TAB_A (5) <= WORD_A; TAB_C (1) <= TAB_A;
    • Indexes of the maximum number of dimensions:
      TAB_A (5) (0) <= '1'; TAB_C (2) (5) (0) <= '0'
    • A slice of the first array
      TAB_A (4 downto 1) <= TAB_B (3 downto 0);
    • An index of a higher level array and a slice of a lower level array:
      TAB_C (2) (5) (3 downto 0) <= TAB_B (3) (4 downto 1); TAB_D (0) (4) (2 downto 0)
      \\ <= CNST_A (5 downto 3)
  3. Add the following declaration:
    subtype MATRIX15 is array(4 downto 0, 2 downto 0) of STD_LOGIC_VECTOR (7 downto 0);
    signal MATRIX_A : MATRIX15;
  4. You can now specify:
    • A multi-dimensional array signal or variable:

      
      MATRIXA <= CNST_A
    • An index of one row of the array:

      
      MATRIXA (5) <= TAB_A;
    • Indexes of the maximum number of dimensions

      
      MATRIXA (5,0) (0) <= '1';
Note: Indexes can be variable.