It's easier to understand how a program works if you execute
by step, seeing the effect on the stack of each step. Doing this can
help you Udebug U your own programs or help you understand pro-
grams written by others.
This section shows you how to execute FIB2 step by step, but you can
apply these rules to any program. The general rules are:
1. Use VISIT to insert the command HALT in the program. Place
HALT where you want to begin single-step execution. (You'll see
how the position of HALT within FIB2 affects execution.)
2. Execute the program. When the HALT command is executed, the
program stops (indicated by the Ustopsign U annunciator).
Select the PROGRAM CONTROL menu.
once to see the next program step displayed and
You can now:
• Keep pressing
to display and execute sequential steps.
to continue normal execution.
to abandon further program execution.
5. When you want the program to run normally again, use VISIT to
remove HALT from the program.
28: Programming Examples