====== Package body ======
===== package_body =====
<code vhdl>
package body package _simple_name is
     package_body_declarative_part
end [ package body ]
        [ package _simple_name ] ;
</code>

===== Further definitions =====
==== simple_name ====
  * [[.:bnf#identifier]]

==== package_body_declarative_part ====
''{ [[.:bnf#package_body_declarative_item]] }''

===== Examples =====
The objects from the library //pck_0// are integrated. In the package body the constant //cint// , which has to be declared in the package header, is declared as integer and initialized with the result value from function call f(6) ([[.:Constant declarations|deferred constant]]).
<code vhdl>
 USE work.pck_0.all;
PACKAGE BODY pck IS
   CONSTANT cint : integer := f(6);
END pck ;
</code>

----

Definition of the package body //pck_1// in which the two functions //G// and //F// are declared.

In the function //G// the value of the equation //A XOR B// is returned as a result (as Bit).

In the function //F// a variable //V// is declared as Bit which then receives the value from //S1 NAND S2// . The function //F// delivers the bit-value from the function call //G(V, S2)// as a result value.
<code vhdl>
PACKAGE BODY pck_1 IS

   FUNCTION G ( A, B : Bit )
      RETURN Bit IS
   BEGIN
      RETURN NOT ( A XOR B );
   END ;

   FUNCTION F ( S1, S2 : Bit )
      RETURN Bit IS
   VARIABLE V : Bit;
   BEGIN
      V := S1 NAND S2;
      RETURN G(V, S2);
   END ;

END pck_1 ;
</code>

----

Definition of the package body //tristate// in which the two functions //BitVal// and //TriVal// are declared.

In the function //BitVal// a constant //Bits// is declared and initialized with the value "0100". As a result, the value of the bit in the position //Tri'Pos// ( //Value// ) of //Bits// is returned.

In the function //TriVal// a variable //V// of the type //Tri// is declared and initialized with the value //Z// .

In **LOOP** either the value of //Source(i)// is transferred to //V// or //E// is returned as a result value, depending on the individual value of //Source(i)// and //V// . In the first case //V// is returned as a result value afterwards.

<code vhdl>
PACKAGE BODY tristate IS

   FUNCTION BitVal ( Value : Tri )
      RETURN Bit IS
   CONSTANT Bits : Bit_Vector := "0100";
   BEGIN
      RETURN Bits(Tri'Pos(Value))
   END ;

   FUNCTION TriVal ( Value : Bit )
         RETURN Tri IS
   VARIABLE V : Tri := 'Z';
   BEGIN
      FOR i IN Sources'Range LOOP
         IF Sources(i) /= 'Z' THEN
            IF V = 'Z' THEN
               V := Sources(i);
            ELSE
               RETURN 'E';
            END IF ;
         END IF ;
      END LOOP ;
   RETURN V ;
   END ;

END tristate ; 
</code>