Section 8: Programming Basics 95
Pressing gÜ while the calculator is in Run mode sets the calculator to the
previous line in program memory, then displays that line’s number and the
keycode of the instruction stored there, just as in Program mode. In Run mode,
however, when the Ü key is released the display again shows the same
number as it did before gÜ was pressed: no instruction in program memory
is executed.
Interrupting Program Execution
Occasionally you’ll want a program to stop executing so that you can see an
intermediate result or enter new data. The HP 12C Platinum provides two
functions for doing so: u (pause) and t (run/stop).
Pausing During Program Execution
When a running program executes a u instruction, program execution halts
for about 1 second, then resumes. During the pause, the calculator displays the
last result calculated before the u instruction was executed.
If you press any key during a pause, program execution is halted indefinitely. To
resume program execution at the program line following that containing the u
instruction, press t.
Example: Create a program that calculates the entries in the AMOUNT, TAX,
and TOTAL columns for each item on the jewelry distributor’s invoice shown on
the next page, and also calculates the total in each of these columns for all items
on the invoice. Assume the sales tax is 6¾%.
To conserve lines of program memory, instead of keying in the tax rate before
the b instruction we’ll store it in register R
0
and recall it before the b
instruction. Before storing the program in program memory, we’ll calculate the
156.25
Result of executing program line
004.
Ê
005, 30
Program line 005: -
468.75
Result of executing program line
005.
Ê
006, 5
Program line 006: 5
5.
Result of executing program line
006.
Ê
007, 40
Program line 007: +
473.75
Result of executing program line
007 (the last line of the program).
Keystrokes
(RPN mode)
Display
