* REPEAT Loops cannot be nested . Only one is allowed to be active per instruction stream at any time.
* REPEAT 0 and PAUSE 0 instructions have no effect, i.e. they are equivalent to NOP.
* Control group (4xxxh) instructions can be logically ORed to produce more complex instructions, e.g. INT|STOP = 4030h = Interrupt and stopStop.
* The STOP instruction will leave the source address register pointing to the next instruction, so that the instruction stream can be continued after CPU intervention.
* The argument field (N) of the REPEAT instruction is actually the number of times the loop is taken. The block of code between REPEAT and LOOP instructions is therefore executed N+1 times.