function RdTSC : int64; register;
asm
  db $0f, $31
end;

function GetCyclesPerSecond : int64;
var
  hF, T, et, sc : int64;
begin
  QueryPerformanceFrequency(hF); // HiTicks / second
  QueryPerformanceCounter(T); // Determine start HiTicks
  et := T + hF; // (Cycles are passing, but we can still USE them!)
  sc := RdTSC; // Get start cycles
  repeat // Use Hi Perf Timer to loop for 1 second
    QueryPerformanceCounter(T); // Check ticks NOW
  until (T >= et); // Break the moment we equal or exceed et
    Result := RdTSC - sc; // Get stop cycles and calculate result
end;

unit HRTimer;

interface

uses Windows;

type

  THRTimer = class(TObject)
    constructor Create;
    function StartTimer: Boolean;
    function ReadTimer: Double;

  private
    StartTime: Double;
    ClockRate: Double;

  public
    Exists: Boolean;

  end;

implementation

constructor THRTimer.Create;
var
  QW: TLargeInteger;

begin
  inherited Create;
  Exists := QueryPerformanceFrequency(QW);
  ClockRate := QW.QuadPart;
end;

function THRTimer.StartTimer: Boolean;
var
  QW: TLargeInteger;

begin
  Result := QueryPerformanceCounter(QW);
  StartTime := QW.QuadPart;
end;

function THRTimer.ReadTimer: Double;
var
  ET: TLargeInteger;

begin
  QueryPerformanceCounter(ET);
  Result := 1000.0 * (ET.QuadPart - StartTime) / ClockRate;
end;

end.

  var
  a,b:Int64;
  i:integer;
begin
  QueryPerformanceCounter(a);

  for i:=0 to 100000 do
    Tag:=Tag+1;

  QueryPerformanceCounter(b);

  Caption:=IntToStr(b-a);