Draw Line Xdot Method

procedure TForm1.BitBtn2Click(Sender: TObject);
//xdot line drawing
type PDW = ^DWORD;
var i : integer;
k : byte;
p,pbase : PDW;
begin
clearBM;
t1 := gettickCount;
pbase := bm.scanline[0];
for i := 1 to 1000000 do
for k := 0 to 99 do
begin
p := PDW(DWORD(pbase) + (k shl 2)- k * 400);
p^ := $0080ff;
end;
t2 := gettickcount;
showtime(100000000);
end;