PDP-8, PDP-8/A, PDP-8/E, PDP-8/F, PDP-8/I, PDP-8/L, PDP-8/M, PDP-8/S, PDP-11, PDP-12, and others in the Krten Collection
This program blinks the AC and MQ lights.
loop, 0000 2020 isz delay / create a delay
0001 5000 jmp loop
0002 7200 cla / clear AC so we can load it
0003 1021 tad value / get value
0004 7421 mql / stash AC into MQ
0005 1021 tad value / fetch value again
0006 7040 cma / complement AC
0007 2021 isz value / get to next value
0010 7000 nop / ignore possible "skip" from ISZ
0011 5000 jmp loop / and do it all again
delay, 0020
value, 0021