procedure FreeAndNil(const [ref] Obj: TObject);
var
  vTmp: TObject;
begin
  if Obj <> nil then
  begin
    vTmp := Obj;
    TObject(Addr(Obj)^) := nil;
    vTmp.Destroy;
  end;
end;

Project1.dpr.12: begin
0041BD90 55               push ebp
0041BD91 8BEC             mov ebp,esp
Project1.dpr.13: if Obj <> nil then
0041BD93 833800           cmp dword ptr [eax],$00
0041BD96 740F             jz $0041bda7
Project1.dpr.15: vTmp := Obj;
0041BD98 8B10             mov edx,[eax]
Project1.dpr.16: TObject(Addr(Obj)^) := nil;
0041BD9A 33C9             xor ecx,ecx
0041BD9C 8908             mov [eax],ecx
Project1.dpr.17: vTmp.Destroy;
0041BD9E 8BC2             mov eax,edx
0041BDA0 B201             mov dl,$01
0041BDA2 8B08             mov ecx,[eax]
0041BDA4 FF51FC           call dword ptr [ecx-$04]
Project1.dpr.19: end;
0041BDA7 5D               pop ebp
0041BDA8 C3               ret 
0041BDA9 8D4000           lea eax,[eax+$00]

procedure FreeAndNil(var Obj);
begin
  TObject(AtomicExchange(Pointer(Obj), nil)).Free;
end;

Project1.dpr.10: begin
0041BD90 55               push ebp
0041BD91 8BEC             mov ebp,esp
Project1.dpr.11: TObject(AtomicExchange(Pointer(Obj), nil)).Free;
0041BD93 33D2             xor edx,edx
0041BD95 F08710           lock xchg [eax],edx
0041BD98 8BC2             mov eax,edx
0041BD9A E88198FEFF       call TObject.Free
Project1.dpr.12: end;
0041BD9F 5D               pop ebp
0041BDA0 C3               ret 
0041BDA1 8D4000           lea eax,[eax+$00]

procedure FreeAndNil(var Obj);
{$IF not Defined(AUTOREFCOUNT)}
var
  Temp: TObject;
begin
  Temp := TObject(Obj);
  Pointer(Obj) := nil;
  Temp.Free;
end;
{$ELSE}
begin
  TObject(Obj) := nil;
end;
{$ENDIF}

Project1.dpr.17: begin
0041BD90 55               push ebp
0041BD91 8BEC             mov ebp,esp
Project1.dpr.18: Temp := TObject(Obj);
0041BD93 8B10             mov edx,[eax]
Project1.dpr.19: Pointer(Obj) := nil;
0041BD95 33C9             xor ecx,ecx
0041BD97 8908             mov [eax],ecx
Project1.dpr.20: Temp.Free;
0041BD99 8BC2             mov eax,edx
0041BD9B E88098FEFF       call TObject.Free
Project1.dpr.21: end;
0041BDA0 5D               pop ebp
0041BDA1 C3               ret 
0041BDA2 8BC0             mov eax,eax

Project1.dpr.26: t := TObject.Create;
0041E5A4 B201             mov dl,$01
0041E5A6 A150144000       mov eax,[$00401450]
0041E5AB E84070FEFF       call TObject.Create
0041E5B0 A3DC684200       mov [$004268dc],eax
Project1.dpr.27: FreeAndNil(t);
0041E5B5 B8DC684200       mov eax,$004268dc
0041E5BA E8D1D7FFFF       call FreeAndNil
0041E5BF 33C0             xor eax,eax

Project1.dpr.19: t := TObject.Create;
0041E5A4 B201             mov dl,$01
0041E5A6 A150144000       mov eax,[$00401450]
0041E5AB E84070FEFF       call TObject.Create
0041E5B0 A3DC684200       mov [$004268dc],eax
Project1.dpr.20: FreeAndNil(t);
0041E5B5 B8DC684200       mov eax,$004268dc
0041E5BA E8D1D7FFFF       call FreeAndNil
0041E5BF 33C0             xor eax,eax

Project1.dpr.31: t := TObject.Create;
0041E5A4 B201             mov dl,$01
0041E5A6 A150144000       mov eax,[$00401450]
0041E5AB E84070FEFF       call TObject.Create
0041E5B0 A3DC684200       mov [$004268dc],eax
Project1.dpr.32: FreeAndNil(t);
0041E5B5 B8DC684200       mov eax,$004268dc
0041E5BA E8D1D7FFFF       call FreeAndNil
0041E5BF 33C0             xor eax,eax

Project1.dpr.26: t := TObject.Create;
0041E5A4 B201             mov dl,$01
0041E5A6 A150144000       mov eax,[$00401450]
0041E5AB E84070FEFF       call TObject.Create
0041E5B0 A3DC684200       mov [$004268dc],eax
Project1.dpr.27: FreeAndNil(t);
0041E5B5 833DDC68420000   cmp dword ptr [$004268dc],$00
0041E5BC 7414             jz $0041e5d2
0041E5BE A1DC684200       mov eax,[$004268dc]
0041E5C3 33D2             xor edx,edx
0041E5C5 8915DC684200     mov [$004268dc],edx
0041E5CB B201             mov dl,$01
0041E5CD 8B08             mov ecx,[eax]
0041E5CF FF51FC           call dword ptr [ecx-$04]
0041E5D2 33C0             xor eax,eax[code]

Project1.dpr.19: t := TObject.Create;
0041E5A4 B201             mov dl,$01
0041E5A6 A150144000       mov eax,[$00401450]
0041E5AB E84070FEFF       call TObject.Create
0041E5B0 A3DC684200       mov [$004268dc],eax
Project1.dpr.20: FreeAndNil(t);
0041E5B5 33C0             xor eax,eax
0041E5B7 F08705DC684200   lock xchg [$004268dc],eax
0041E5BE E85D70FEFF       call TObject.Free
0041E5C3 33C0             xor eax,eax

Project1.dpr.30: t := TObject.Create;
0041E5A4 B201             mov dl,$01
0041E5A6 A150144000       mov eax,[$00401450]
0041E5AB E84070FEFF       call TObject.Create
0041E5B0 A3DC684200       mov [$004268dc],eax
Project1.dpr.31: FreeAndNil(t);
0041E5B5 A1DC684200       mov eax,[$004268dc]
0041E5BA 33D2             xor edx,edx
0041E5BC 8915DC684200     mov [$004268dc],edx
0041E5C2 E85970FEFF       call TObject.Free
0041E5C7 33C0             xor eax,eax

Project1.dpr.31: t.Free;
0041E5F4 8BC3             mov eax,ebx
0041E5F6 E82570FEFF       call TObject.Free
0041E5FB 33C0             xor eax,eax