Hi Bart,
i have noticed what i believe is an ERROR in your code.
I was reading through it to see how it worked and i came across this piece of text.
1120 ON (RES AND &HF0)/16+1 GOSUB 1121,1121,1123,1124:RETURN
1121 PRINT "RLCA";:RETURN
1122 PRINT "RLA";:RETURN
1123 PRINT "DAA";:RETURN
1124 PRINT "SCF";:RETURN
The Error is in line 1120, You have 2 Gosub's with the same address jump " 1121"
I think the second one is meant to be 1122 if you are following the sequence of jumps.
There does not seem to be a gosub or jump to 1122 in the code.
If i am in error just delete this message, but you might want to fix it
and re upload it to here and github as it is incorrect there aswell before
it is downloaded a million times.
Thanks ... AJ