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From: "Beard, Frank Randolph CIV" <frank.beard@navy.mil>
Newsgroups: comp.lang.ada
Subject: RE: Bitwise XOR?
Date: Fri, 3 Oct 2003 06:28:15 -0400
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Thread-Topic: Bitwise XOR?
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Xref: archiver1.google.com comp.lang.ada:144
Date: 2003-10-03T06:28:15-04:00

You don't even need the Unchecked_Conversion.

The following should work:

  function "xor"(Left,Right : in Integer) return Integer is
    pragma inline("xor");
    type Int_As_Mod is mod 2 ** Integer'size;
  begin
    return Integer( Int_As_Mod(Left) XOR Int_As_Mod(Right) );
  end "xor";

Theoretically, Unchecked_Conversion should be faster I guess.
Is that why you chose it, or did you do some timing tests
that showed a noticeable difference?

Frank

-----Original Message-----
From: Steve

Ada 95 permits using XOR on modular types.
If you want to XOR between integers, convert the integer to a modular =
type,
do the XOR,
then convert the result back.  The following (tested) routine does =
exactly
this.

  function "xor"(Left,Right : in Integer) return Integer is
    pragma inline("xor");
    type Int_As_Mod is mod 2 ** Integer'size;
    function To_Mod is new Ada.Unchecked_Conversion( Integer, Int_As_Mod =
);
    function To_Int is new Ada.Unchecked_Conversion( Int_As_Mod, Integer =
);
  begin
    return To_Int( To_Mod(Left) XOR To_Mod(Right) );
  end "xor";

Steve
(The Duck)