Re: bit operations on integers

["David C. Hoos, Sr." <david.c.hoos.sr@ada95.com>]

phadreus@iname.com wrote in message <7gkhr7$5kr$1@nnrp1.dejanews.com>...
>
>
>How do I test, set, and clear individual bits in an integer
>in Ada 83?
>
How about:

package Bit_Ops is

   function Test
     (Item : Integer;
      N    : Natural)
      return Boolean;

   procedure Set
     (Item : in out Integer;
      N    :        Natural);

   procedure Clear
     (Item : in out Integer;
      N    :        Natural);

end Bit_Ops;

package body Bit_Ops is

   type Bit_Array is
      array (Natural range 0 .. Integer'Size - 1)
     of Boolean;
   pragma Pack (Bit_Array);


   -----------
   -- Clear --
   -----------

   procedure Clear
     (Item : in out Integer;
      N    :        Natural)
   is
     Bits : Bit_Array;
     for Bits use at Item'Address;
   begin
      Bits (N) := False;
   end Clear;

   ---------
   -- Set --
   ---------

   procedure Set
     (Item : in out Integer;
      N    :        Natural)
   is
     Bits : Bit_Array;
     for Bits use at Item'Address;
   begin
      Bits (N) := True;
   end Set;

   ----------
   -- Test --
   ----------

   function Test
     (Item : Integer;
      N    : Natural)
      return Boolean
   is
     Bits : Bit_Array;
     for Bits use at Item'Address;
   begin
      return Bits (N);
   end Test;

end Bit_Ops;