--An example for a module using package..
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
--use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
use IEEE.numeric_std.all;

--note this line.The package is compiled to this directory by default.
--so don't forget to include this directory.
library work;
--this line also is must.This includes the particular package into your program.
use work.test_pkg.all;

entity tutora is
port (clk : in std_logic;
		o : out unsigned(7 downto 0);
		a, b : in unsigned(7 downto 0));
end tutora;

architecture Behavioral of tutora is

signal c : unsigned(7 downto 0) :=(others => '0');
begin
process(clk)
begin
	if(clk'event and clk='1') then
	c<=divide( a , b ); 
	o<=c;
end if;
end process;
end Behavioral;



--Package declaration for the above program
library IEEE;
use IEEE.std_logic_1164.all;
--use IEEE.std_logic_arith.all;
use IEEE.numeric_std.all;

package test_pkg is
 --function declaration.
function divide(a : UNSIGNED; b: UNSIGNED) return UNSIGNED;
end test_pkg;   --end of package.

package body test_pkg is  --start of package body
--definition of function
function divide(a : UNSIGNED; b: UNSIGNED) return UNSIGNED is
variable a1 : unsigned(a'length-1 downto 0):=a;
variable b1 : unsigned(b'length-1 downto 0):=b;
variable p1 : unsigned(b'length downto 0):=(others => '0');
variable i : integer:=0;

begin -- Just name the fields in order...
for i in 0 to b'length-1 loop
p1(b'length-1 downto 1) := p1(b'length-2 downto 0);
p1(0) := a1(a'length-1);
a1(a'length-1 downto 1) := a1(a'length-2 downto 0);
p1 := p1-b1;
if(p1(b'length-1) ='1')then
	a1(0) := '0';
	p1 := p1+b1;
else
	a1(0) := '1';
end if;
end loop;
return a1;

end divide;	
--end function
end test_pkg;  --end of the package body