depending on bit 7 multiplexer 1003 selects the counter of write position pointer 1004 or the counter of read position pointer 1005 after the data has been added subtracted state machine 1011 activates gate 1010 and sends a receive signal to counter 1004 1005 thus the selected position pointer points as many positions forward or backward as set forth in the data of the skip command upon a goto command gate 1007 is activated by state machine 1011 so that the data goes to read position pointer 1005 or write position pointer 1004 and is received there upon a mask command the data is received in a latch 1008 and stored there this data is then available to the controller described in fig7 7 a via line a 1013 where it masks all the trigger inputs which should receive no trigger pulse upon a wait command an event is waited for as often as set forth in the data bits if this command is registered by state machine 1011 it sends a pulse to wait cycle counter 1009 which receives the data the wait cycle counter then counts one position downward for each event relayed by state machine 1011 as soon as it has counted to zero the carry flag is set and sent to state machine 1011 1023 the state machine then continues to operate due to the carry flag upon a.