HP HP-25 - Page 96

tions one at a time. When you hold the g key down in RUN
mode, the program step number and keycode are displayed.
When you release the key, the instruction is executed. Use
B3l on the simple area of a circle program shown below to
familiarize yourself with its operation.
Example Program. This program calculates the area of a
circle using the formula: 4 = 7r* where r is the radius. Set the
PRGM-RUN switch to PRGM erew[[[[Ml~~ and press |
to clear program memory and display step 00. Then key
in the list of keys shown below.
Press Display
a 01 __15 02
a 0215 73
03 61
The program assumes that a value for r has been keyed into the
X-register. To run the program, set the PRGM-RUN switch
back to RUN encu Bl »n and press | . Now step
through the program in slow motion using a value of 10 for r.
Press Display
10
el When you hold B down, the
first instruction is displayed.
i
When you release B34, the first
instruction is executed.
sl Again holding Eg@ down displays
the second instruction.
Again releasing Ejexecutes the
second instruction.
S Holding & down displays the
third instruction this time.
And releasing g3 executes the
third instruction.
You can see that it would be easy to spot a mistake in your pro-
gram using the B3 key.