HP -67 Owner's Handbook Manual page 220

216 Controlling the I-Register
Press Display
0 (sz) Adds 1 to I-register.
O 005 22 11] If contents of I-register
are not zero, execution
transfers back to B.
1 006 01| If contents of I-register
are zero, 1 is placed in
I-register.
0
0 008 22 11
0 009 35 22
Now run the program beginning with a value of O in the I-register.
Stop the program after five iterations or so by pressing (R/S).
Slide the W/PRGM-RUN switch weram [l run to RUN.
Press Display
W h Zerostored in I-register.
o
Although the (5Z] and instructions increment and decrement the
L-register by 1, the value of the I-register need not be a whole
number.
For example:
Press Display
52860 0
o
RIS