TOPIC:

  procedure JoinBlock(const L, R : LongInt;  var Block : TDESBlock); register;
  asm
    push ebx
    mov  bh, al
    mov  bl, ah
    rol  ebx, 16
    shr  eax, 16
    mov  bh, al
    mov  bl, ah
    mov  [ecx+4], ebx  <- debugger shows this line
    mov  bh, dl
    mov  bl, dh
    rol  ebx, 16
    shr  edx, 16
    mov  bh, dl
    mov  bl, dh
    mov  [ecx], ebx
    pop  ebx
  end;

     TDesConverter = record
     case boolean of
        false: (Bytes: array [0..7] of byte);
        true: (DWords: array  [0..1] of dword)
   end;

{$IFDEF CPU32}

  procedure SplitBlock(const Block : TDESBlock; var L, R : DWord);
  var
   Temp: TDesConverter;
   I: integer;
  begin
    for I := Low(Block) to High(Block) do
    Temp.Bytes[7-I] := Block[I];
    L:= Temp.DWords[1];
    R:= Temp.DWords[0];
  end;

  procedure JoinBlock(const L, R : LongInt; var Block : TDESBlock);
  var
     Temp: TDesConverter;
     I: integer;
  begin
       Temp.DWords[0] := DWord(L);
       Temp.DWords[1] := DWord(R);
       for I := Low(Block) to High(Block) do
           Block[I] := Temp.Bytes[7-I];
  end;

procedure XorMemPrim(var Mem1; const Mem2; Count : Cardinal);
var
   i: Integer;
   p1,p2: NativeInt;
begin
   p1 := NativeInt(@Mem1);
   p2 := NativeInt(@Mem2);
   for i := 1 to count div 4 do
   begin
     PDWord(p1)^ := PDWord(p1)^ xor PDWord(p2)^;
     p1 := p1 + 4;
     p2 := p2 + 4;
   end;
   for i:=1 to count mod 4 do
   begin
     PByte(p1)^ := PByte(p1)^ xor PByte(p2)^;
     p1 := p1 + 1;
     p2 := p2 + 1;
   end;
end;

function RolX(I, C : DWord): DWord;
begin
   Result := (I shl (C and 31)) or (I shr (32-(C and 31)));
end;

    Block[0] := 0;//DateTimeToFileDate(now);
    Block[1] := 0;//DateTimeToFileDate(now);
    Block[2] := 0;//DateTimeToFileDate(now);
    Block[3] := 0;//DateTimeToFileDate(now);