Fill Rectangle XFillrect Method

procedure TForm1.BitBtn7Click(Sender: TObject);
//xdot fill timing
type PDW = ^DWORD;
var x,y : byte;
k : word;
p,pbase,pline : PDW;
begin
clearBM;
t1 := gettickCount;
pbase := bm.scanline[0];
for k := 1 to 10000 do
for y := 0 to 99 do
begin
pline := PDW(DWORD(pbase) - y*400);
for x := 0 to 99 do
begin
p := PDW(DWORD(pline) + (x shl 2));
p^ := $0080ff;
end;
end;
t2 := gettickcount;
showtime(100000000);
end;