- new proc_is_runnable() macro to test whether process is runnable. All tests
whether p_rts_flags == 0 converted to use this macro
- pick_proc() calls removed from enqueue() and dequeue()
- removed the test for recursive calls from pick_proc() as it certainly cannot
be called recursively now
- PREEMPTED flag to mark processes that were preempted by enqueueuing a higher
priority process in enqueue()
- enqueue_head() to enqueue PREEMPTED processes again at the head of their
current priority queue
- NO_QUANTUM flag to block and dequeue processes preempted by timer tick with
exceeded quantum. They need to be enqueued again in schedcheck()
- next_ptr global variable removed
daf7940c69