Delphi Implement a microsecond resolution Delay

Implement a microsecond resolution Delay?
Author: Lemy
Homepage: http://www.swissdelphicenter.com

// Wait 0.2ms

procedure PerformanceDelay;

var
hrRes, hrT1, hrT2, dif: Int64;
begin
     if QueryPerformanceFrequency(hrRes) then
     begin
        QueryPerformanceCounter(hrT1);
        repeat
            QueryPerformanceCounter(hrT2);
               dif := (hrT2 - hrT1) * 10000000 div hrRes;
        until dif > 2;
     end;
end;