help in sintax for various inputs to single internal signal vector binary and decimal

--- Quote Start ---

dout <= to_integer(signed(interna_data));

it needs library numeric_std

--- Quote End ---

ok,, in my code when compile, generate multiple output pins, not a single pin "deci" why?

library ieee;

use ieee.std_logic_1164.all;

use ieee.numeric_std.all;

entity joystick is

port

(

d1,d2,d3,d4,d5,d6,d7,d8 : in std_logic;

deci : out integer range 0 to 255) ;

end joystick;

architecture lectura of joystick is

signal val_bin : std_logic_vector(7 downto 0);

begin

val_bin <= d8 & d7 & d6 & d5 & d4 & d3 & d2 & d1;

deci <= to_integer(signed(val_bin));

end lectura;

i can save this output in one only value for send these after data to a serial COM for using in a program in PC? my code generate various output pins.