Section 4: Programming 150
For ease of recognition, the digit keys 0, . . . , 9 are displayed as 00, . . . , 09. You can now read the remaining contents of memory.
Press   See Displayed   Comment
   
  23
  Represents LBL.
SST   
  11
  Represents A.
SST   
  35
  Represents g.
SST   
  04
  Represents 1/x  .
SST   
  24
  Represents RTN.
Etc.   Etc.    
Thus, starting at the top, you can now see that the first live codes (23, 11, 35, 04, 24) represent the default function defined for the top row A key. This function, LBL A g1/x RTN, does nothing more than compute the reciprocal of x.
The SST key is discussed in Figure 4-1. Note that SST is used also in RUN mode to execute a program, one step at a time.
Also, note that to conserve memory, the most frequently used prefix-suffix pairs are each merged into single codes. Thus, gLSTX is encoded and displayed as:
 

Control Operations

In creating a program, you take into account how it is to be started and how it is to stop. You may recall that in the function created in the Introduction, you put a label (LBL A) ahead of the actual calculating steps so that the beginning of the program could be found. You also put a return (RTN) at the end so that the program could stop itself:
LBL A ENTER  ENTER  × × RTN
   Notice that 35, representing the g prefix, determines that the next code 04 be interpreted as 1/x, the blue alternate function on the 4 key.