private void decrementWorkerCount(){
  for (; ; ) {
    int c=ctl.get();
    if (ctl.compareAndSet(c,ctlOf(runStateOf(c),workerCountOf(c) - 1)))     break;
  }
}

private void decrementWorkerCount ( ) { for ( ; ; ) { int c = ctl . get ( ) ; if ( ctl . compareAndSet ( c , ctlOf ( runStateOf ( c ) , workerCountOf ( c ) - 1 ) ) ) break ; } }
decrements the workercount field of ctl . this is called only on abrupt termination of a thread ( see processworkerexit ) . other decrements are performed within gettask .
