the address of Self in constructor in freepascal?

Question

Below is the output of test code.

Why are the addresss of instance(@a) and the address of Self(@Self) in constructor different?

I think both should be the same. The addresss of class instance and the address of this in constructor are same in c++.

Is it possible to get the address equal to the addresss of instance(@a) in constructor?

Lazarus 2.2.0 64bit for windows.

@Self=00000000013FFDC8
@a=00000000013FFE38
a.i=3
a_ptr^.i=3
ga_ptr^.i=5872  << invalid value

    unit unitmain;
     
    {$mode ObjFPC}{$H+}
     
    interface
     
    uses
        Classes, SysUtils;
     
    type
        ClassA = class
        public
            constructor Create(i : Integer);
            var
                i : Integer;
        end;
        PClassA = ^ClassA;
     
    var
        ga_ptr : PClassA;
     
    procedure TestSelfAddr();
     
    implementation
     
    constructor ClassA.Create(i : Integer);
    begin
        Self.i := i;
        ga_ptr := @Self;
        Writeln(Format('@Self=%P', [@Self]));
    end;
     
    procedure TestSelfAddr();
    var
        a : ClassA = nil;
        a_ptr : PClassA = nil;
    begin
        a := ClassA.Create(3);
        a_ptr := @a;
     
        Writeln(Format('@a=%P', [@a]));
        Writeln(Format('a.i=%d', [a.i]));
        Writeln(Format('a_ptr^.i=%d', [a_ptr^.i]));
        Writeln(Format('ga_ptr^.i=%d', [ga_ptr^.i]));   // << invalid value
    end;
     
    end.