uses DateUtils;

function MicrosecondsToTime(const microSeconds : TLargeInteger) : string;
CONST
  MicroPerMilli = 1000;
var
  dt : TDateTime;
  microSec : TLargeInteger;
begin
  dt := microSeconds / MicroPerMilli / MSecsPerSec / SecsPerDay;

  microSec := microseconds - MicroPerMilli * MilliSecondOf(dt) ;

  if microsec < 0 then
  begin
    dt := IncMilliSecond(dt,-1) ;
    microsec := MicroPerMilli + microsec;
  end;

  result := Format('%d days, %s %d', FormatDateTime[/link">('hh:nn:ss.z', Frac(dt)), microSec]) ;
end;

function MSecToTime(mSec: Int64): string;
 var
   dt : TDateTime;
 begin
    dt := mSec / MSecsPerSec / SecsPerDay;
    Result := Format('%d days, %s', ) ;
 end;