Section 8: Programming Basics 95Pressing gÜ while the calculator is in Run mode sets the calculator to theprevious line in program memory, then displays that line’s number and thekeycode 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 samenumber as it did before gÜ was pressed: no instruction in program memoryis executed.Interrupting Program ExecutionOccasionally you’ll want a program to stop executing so that you can see anintermediate result or enter new data. The HP 12C Platinum provides twofunctions for doing so: u (pause) and t (run/stop).Pausing During Program ExecutionWhen a running program executes a u instruction, program execution haltsfor about 1 second, then resumes. During the pause, the calculator displays thelast result calculated before the u instruction was executed.If you press any key during a pause, program execution is halted indefinitely. Toresume program execution at the program line following that containing the uinstruction, 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 onthe next page, and also calculates the total in each of these columns for all itemson the invoice. Assume the sales tax is 6¾%.To conserve lines of program memory, instead of keying in the tax rate beforethe b instruction we’ll store it in register R0 and recall it before the binstruction. Before storing the program in program memory, we’ll calculate the156.25 Result of executing program line004.Ê 005, 30 Program line 005: -468.75 Result of executing program line005.Ê 006, 5 Program line 006: 55. Result of executing program line006.Ê 007, 40 Program line 007: +473.75 Result of executing program line007 (the last line of the program).Keystrokes(RPN mode) Display
