HP HP-67 - Page 152

148 Program Editing
0 (back step) is a nonrecordable operation that displays the
previous step of program memory. When you press [ with the
W/PRGM-RUNsswitch werem [[[[IllRuN set toW/PRGM, the calcula-
tor moves to and displays the previous step of program memory.
When you press and release and then press down with the
W/PRGM-RUN switch werem [l RuN set to RUN, the calculator
moves to and displays the contents of the previous step of program
memory. When you then release , the original contents of the
X-register are displayed. No instructions are executed.
(go to) (] (n) (0] (n) is another keyboard operation that cannot be
loaded as an instruction. ([5ife] I3 or 8 followed by any other label,
however, can be loaded as a program instruction. More about the use
of this instruction later.) Whether the Program Mode switch is set to
RUN or W/PRGM, when you press (<] followed by a three-digit
step number, the calculator transfers execution so that the next opera-
tion or instruction will begin at that step number. No instructions are
executed. If the calculator is in RUN mode, you can verify that the
calculator is set to the specified step by briefly sliding the Program
Mode switch wierem [[[[JlJrun to W/PRGM. The MO Mm
operation is especially useful in W/PRGM mode because it permits
you to jump to any location in program memory for editing of or
additions or corrections to your programs.
The (delete) key is a nonrecordable operation that you can use to
delete instructions from program memory. When the Program Mode
switch wpram [[[IMlruN is set to W/PRGM and you press ,
the instruction at the current step of program memory is erased, and
all subsequent instructions in program memory move upward one
step. The section of program memory shown below illustrates what
would happen when you press (3 with the calculator set to step
004.