Program Boundaries (LBL and RTN)

If you want more than one program stored in program memory, then a program needs a label to mark its beginning (such as   ) and a return to mark its end (such as  !).

Notice–that the line numbers acquire an  to match their label.

Program Labels

Programs and segments of programs (called routines) should start with a label. To record a label, press:

zĀ“letter–key

The label is a single letter from A through Z. The letter keys are used as they are for variables (as discussed in chapter 3). You cannot assign the same label more than once (this causes the message "!)), but a label can use the same letter that a variable uses.

It is possible to have one program (the top one) in memory without any label. However, adjacent programs need a label between them to keep them distinct.

Program Line Numbers

Line numbers are preceded by the letter for the label, such as .

If one label's routine has more than 99 lines, then the line number appears with a decimal point instead of the leftmost number, such as ) for line 101 in label A. For more than 199 lines, the line number uses a comma, such as 8 for line 201.

Program Returns

Programs and subroutines should end with a return instruction. The keystrokes are:

{Ā”

When a program finishes running, the last RTN instruction returns the program pointer to  !, the top of program memory.

Simple Programming 12–3

File name 32sii-Manual-E-0424

 

Printed Date : 2003/4/24

Size : 17.7 x 25.2 cm