Call Procedure inside Function

Altera_Forum · ‎05-08-2010

Hi, i have a question: How can i call a Procedure inside of a Function?

The Quartus show me: VHDL error at Decod.vhd(150): cannot access 'maissig' from inside pure function 'soma'.

my code:


library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
entity Decod is
    port
    (
        CLK        : in  std_logic;                          -- SINAL DE CLOCK
        Dados    : in  std_logic_vector (7 downto 0);
        Ch_A    : in  std_logic;
        Ch_B    : in  std_logic;
        Ch_C    : in  std_logic;
        
        out3    : out integer;
        out4    : out integer;
        Disp1    : out std_logic_vector(7 downto 0);
        Disp2    : out std_logic_vector(7 downto 0);
        Disp3    : out std_logic_vector(7 downto 0));
end Decod;
architecture Funcao of Decod is
    type   Chave is (Zero, Um, Dois, Tres, Quatro, Cinco, Seis, Sete);
    signal Estado   : Chave := Zero;
    signal word        : std_logic_vector (11 downto 0) := "000000000000";
    signal D1       : integer range 0 to 15;
    signal D2       : integer range 0 to 15;
    signal D3       : integer range 0 to 15;
    signal MaisSig  : std_logic_vector (7 downto 0) := "00000000";    
    signal MenosSig : std_logic_vector (7 downto 0) := "00000000";
    signal H_Alto   : integer;
    signal H_Baixo  : integer;
    signal a        : std_logic_vector(3 downto 0);
    signal b        : std_logic_vector(3 downto 0);
    PROCEDURE Nibble (       Vetor    : in std_logic_vector (7 downto 0);
                      signal P_alta  : out std_logic_vector (7 downto 0);
                      signal P_baixa : out std_logic_vector (7 downto 0)) is
    BEGIN
        P_alta  (3 downto 0) <= Vetor(7 downto 4);
        P_baixa (3 downto 0) <= Vetor(3 downto 0);
    END Nibble;
    FUNCTION Soma ( Vetor     : std_logic_vector (7 downto 0);
                    a : integer; b : integer) RETURN INTEGER IS
        
        variable Som : integer range 0 to 30 := 0;
        variable V_a : std_logic_vector (7 downto 0);
        variable V_b : std_logic_vector (7 downto 0);
        
    BEGIN
        Nibble (Vetor(7 downto 0), MaisSig(7 downto 0), MenosSig(7 downto 0));
        V_a := MaisSig;
        V_b := MaisSig;
        a := Decimal(V_a(7 downto 0));
        b := Decimal(V_b(7 downto 0));
        Som := a + b;
        RETURN Som;
    END Soma;         
end funcao;

Please, where the error?

Altera_Forum · ‎05-08-2010

pure functions can only access internal variables.

To access varaibles outside the function, you either need to pass them into the function (VIA the inputs) or declare the function as impure:

impure function soma(..) return integer is....

I wouldnt do this though as you're trying to read signals. I would pass them in as function inputs.