- Uncomment the following library declaration if using
-- arithmetic functions with Signed or Unsigned values
--use IEEE.NUMERIC_STD.ALL;

-- Uncomment the following library declaration if instantiating
-- any Xilinx primitives in this code.
--library UNISIM;
--use UNISIM.VComponents.all;

entity Somador8bits is
    port(
        operandoA, operandoB: in std_logic_vector(7 downto 0);
        operacao: in std_logic;
        ValorAlto, ValorBaixo: out std_logic_vector(6 downto 0);
        flag_Z, flag_N, flag_C, flag_V: out std_logic
        );
end Somador8bits;

architecture Soma8 of Somador8bits is
    signal Bi,n: std_logic_vector(7 downto 0);
    signal s1, s2: std_logic_vector(3 downto 0);
    signal c: std_logic;
begin
    A0: entity work.Somador1bit port map(cin=>c, a=>operandoA(0), b=>Bi(0), cout=>n(0), s=>s1(0));
    A1: entity work.Somador1bit port map(cin=>n(0), a=>operandoA(1), b=>Bi(1), cout=>n(1), s=>s1(1));
    A2: entity work.Somador1bit port map(cin=>n(1), a=>operandoA(2), b=>Bi(2), cout=>n(2), s=>s1(2));
    A3: entity work.Somador1bit port map(cin=>n(2), a=>operandoA(3), b=>Bi(3), cout=>n(3), s=>s1(3));
    A4: entity work.Somador1bit port map(cin=>n(3), a=>operandoA(4), b=>Bi(4), cout=>n(4), s=>s2(0));
    A5: entity work.Somador1bit port map(cin=>n(4), a=>operandoA(5), b=>Bi(5), cout=>n(5), s=>s2(1));
    A6: entity work.Somador1bit port map(cin=>n(5), a=>operandoA(6), b=>Bi(6), cout=>n(6), s=>s2(2));
    A7: entity work.Somador1bit port map(cin=>n(6), a=>operandoA(7), b=>Bi(7), cout=>n(7), s=>s2(3));

    with operacao select
        Bi<= not operandoB when '1',
              operandoB when '0';

    with s1 select
         ValorBaixo<= "1111110" when "0000",
                          "0110000" when "0001",
                          "1101101" when "0010",
                          "1111001" when "0011",
                          "1100011" when "0100",
                          "1110011" when "0101",
                          "1011111" when "0110",
                          "1110010" when "0111",
                          "1111111" when "1000",
                          "1100111" when "1001",
                          "1110111" when "1010",
                          "0011111" when "1011",
                          "1001110" when "1100",
                          "0111101" when "1101",
                          "1001111" when "1110",
                          "1000111" when "1111";

    with s2 select
        ValorAlto<= "1111110" when "0000",
                        "0110000" when "0001",
                        "1101101" when "0010",
                        "1111001" when "0011",
                        "1100011" when "0100",
                        "1110011" when "0101",
                        "1011111" when "0110",
                        "1110010" when "0111",
                        "1111111" when "1000",
                        "1100111" when "1001",
                        "1110111" when "1010",
                        "0011111" when "1011",
                        "1001110" when "1100",
                        "0111101" when "1101",
                        "1001111" when "1110",
                        "1000111" when "1111";

    flag_Z<= '1' when s1 & s2=x"0" else '0';
    flag_N<= '1' when s1 & s2<x"0" else '0';
    flag_C<= n(7);
    flag_V<= '1' when ((operacao='1') and ((operandoA>x"0" and Bi>x"0" and S1 & S2<x"0") or (operandoA<x"0" and Bi<x"0" and S1 & S2>x"0"))) or
    ((operacao='0') and ((operandoA>x"0" and Bi>x"0" and S1 & S2<x"0") or (operandoA<x"0" and Bi<x"0" and S1 & S2>x"0")))
    else '0';
end Soma8;