Section 14: Flags213
For example, if flag 00 is set and you use FS? , the display will show YES. on the other hand, if flag 00 is set and you use FC? . the display will show NO.
Try testing flags 00 and 01 using FS? .
Keystrokes Display    
g FS? 00 
  Flag 00 was set in an earlier example, so the answer to the test is YES . Notice that the display annunciator shows 0.
g FS? 01 
  Since flag 01 is not set, the calculator returns an answer of NO.
Example: The following program contains an infinite loop that illustrates the operation of a flag. The program alternately displays SET and CLEAR by changing and testing the status of flag 00. A flowchart for this simple program might look like the one below.
The program assumes that flag 00 is initially set.
Display SET
Clear flag 00
Is flag 00 set?
      No No        
Display CLEAR
Set flag 00