Call Procedure inside Function

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

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;