left bound (21) fo slice must belong to range & formal port or parameter must have actual or default value

[ksubi]

I have two errors. "left bound (21) of slice must belong to range (18 downto 0) of corresponding object" and "formal port of parameter "x_i" must have actual or default value". 

How can I fix it?

Here is a code

----Booth_multi----

library ieee;

use ieee.std_logic_1164.all;

use ieee.std_logic_arith.all;

use ieee.std_logic_unsigned.all;

entity Booth_multi is

  port ( a : in std_logic_vector(15 downto 0); -- 16비트의 입력 a

      b : in std_logic_vector(15 downto 0); -- 16비트의 입력 b

    p : out std_logic_vector(31 downto 0)); -- 32비트의 출력 p

end Booth_multi;

architecture behavior of Booth_multi is

component booth_unit

  Port ( P : in std_logic_vector(15 downto 0);

      Y : in std_logic_vector(15 downto 0);

      x_i : in std_logic_vector(3 downto 0);

  Z  : out std_logic_vector(2 downto 0);

  P_n : out std_logic_vector(15 downto 0));

end component;

type conections is array (0 to 7) of std_logic_vector (15 downto 0);

Signal wires: conections;

Signal eX: std_logic_vector (18 downto 0);

constant bitsCalc : integer := (3-(16 mod 3)) mod 3; -- bit 계산

begin

 eX <= a(15) & a(15) & a & '0'; --ex는 a(15)a(15)a0이 된다.

 wires(0) <= (others => '0');

 iter: for i in 0 to 7 generate

  mult: booth_unit port map (P => wires(i), Y => b, x_i => eX(3*i+3 downto 3*i), 

     Z => p(3*i+2 downto 3*i), P_n => wires(i+1) ); -- booth_unit 포트를 연결

 end generate;

 p(31 downto 16+bitsCalc) <= wires(6)(16-bitsCalc-1 downto 0);

end behavior;

-----Booth_unit----

library ieee;

use ieee.std_logic_1164.ALL;

use ieee.std_logic_arith.ALL;

use ieee.std_logic_unsigned.ALL;

entity Booth_unit is

  Port ( P : in std_logic_vector(15 downto 0);

      Y : in std_logic_vector(15 downto 0); 

      x_i : in std_logic_vector(3 downto 0);

  Z : out std_logic_vector(2 downto 0);

  P_n : out std_logic_vector(15 downto 0)

     );

end Booth_unit;

architecture behavior of Booth_unit is

signal S, Long_P, Long_Y, Long_Y_2 , Long_Y_3, Long_Y_4: std_logic_vector(18 downto 0);

begin

Long_P <= P(15) & P(15) & P(15) & P;

Long_Y <= Y(15) & Y(15) & Y(15) & Y;

Long_Y_2 <= Y(15) & Y(15) & Y & '0';

Long_Y_3 <= Long_Y + Long_Y_2;

Long_Y_4 <= Y(15) & Y & "00";

the_mux: process(x_i,Long_P, Long_Y, Long_Y_2, Long_Y_3, Long_Y_4)

begin

  case x_i is

   when "0000" => S <= Long_P;

   when "0001" => S <= Long_P + Long_Y;

   when "0010" => S <= Long_P + Long_Y;

   when "0011" => S <= Long_P + Long_Y_2;

   when "0100" => S <= Long_P + Long_Y_2;

   when "0101" => S <= Long_P + Long_Y_3;

   when "0110" => S <= Long_P + Long_Y_3;

   when "0111" => S <= Long_P + Long_Y_4;

   when "1000" => S <= Long_P - Long_Y_4;

   when "1001" => S <= Long_P - Long_Y_3;

   when "1010" => S <= Long_P - Long_Y_3;

   when "1011" => S <= Long_P - Long_Y_2;

   when "1100" => S <= Long_P - Long_Y_2;

   when "1101" => S <= Long_P - Long_Y;

   when "1110" => S <= Long_P - Long_Y;

   when "1111" => S <= Long_P;

 when others => NULL;

  end case;

end process;

P_n <= S(18 downto 3);

Z  <= S(2 downto 0); 

end behavior;

[mfro]

You are exceeding the allowed range for x_i. It is defined as

Signal eX: std_logic_vector (18 downto 0);

, but later on, you attempt to iterate across it like this:

iter: for i in 0 to 7 generate mult : booth_unit port map ( P => wires(i), Y => b, x_i => eX(3*i+3 downto 3*i), Z => p(3*i+2 downto 3*i), P_n => wires(i+1) ); -- booth_unit end generate;

Note: you are iterating i from 0 to 7, but 3 * 6 + 3 is already exceeding the bounds of the vector. No idea what you are trying to do, but the loop should probably go from 0 to 5 only...

The second error is most likely only a consequence of the first.