HP -67 Owner's Handbook Manual page 160

156 Program Editing
Now let's see what happened in program memory when you loaded
that instruction. With the calculatorset at step 001, when you pressed
B program memory was altered...
...from this... ...to this.
001 B ([MA3 001 [ 8 8 instruction
002 ) fl ~ 002 3 < jnserted here.
003 @ (* ~ 008 8 ) |
004 1 004 )
005 N5 B
006 :: 006
007 @ ~a 007 (2 (7 All subsequent
008 008 - .
N nstructions are
009 009 (R/S e '
Na bumped'' down one
010 010 step of program
011 (R/S 011 memory.
AN
221 N 221 (R/S
222 ~ 222
223 ~ 223
224 (R/s 224
\ R/S One instruction lost
here.
You can see that when you insert an instruction in a program, all
instructionsafter the one inserted are moved down one step of program
memory, and the instruction formerly loaded in step 224 is lost and
cannot be recovered. In this case, the last instruction was a
instruction and was not used in the program. Note, however, that if
you inserted an instruction into program memory when step 224
contained an instruction used in a program, the instruction would
be lost from step 224. You should always view the contents of
the last few steps of program memory before adding instructions to a
program to ensure that no vital instructions will be lost from there.