HP HP-67

Simple Programming 137
Press Display
8 002 32 54
0 003 35 73
a8 004 71
0 005 35 22
The program for solving the area of a circle given its radius is now
loaded into program memory of the HP-67. Notice that nothing could
be loaded into the top-of-memory marker, step 000.
Running a Program
To run a program, you have only to slide the W/PRGM-RUN switch to
RUN, key in any ‘‘unknown’’ data that is required, and press the letter
key (I3 through (&, 7 (3 through [ (€)) that labels your program.
For example, to use the program now in the calculator to solve for
circles with radii of 3 inches, 6 meters, and 9 miles:
First, slide the W/PRGM-RUN switch werem ll[[Irun to RUN.
Press Display
308 28.27 Square inches.
60 113.10 Square meters
I3 254.47 Square miles.
Now let’s see how the HP-67 executed this program.
Searching for a Label
When you switched the W/PRGM-RUN switch weram [ll[[Irun to
RUN, the calculator was set at step 005 of program memory, the last
step you had filled with an instruction when you were loading the
program. When you pressed the I3 key, the calculator began search-
ing sequentially downward through program memory, beginning with
that step 005, for a I3 instruction. When the calculator searches,
it does not execute instructions.
The calculator reached the last step of program memory, step 224,
without encountering an [ P3 instruction. It then passed
step 000 again and continued searching sequentially through program
memory for a 3 instruction. Only when the calculator found an
a 3 instruction in step 001 did it begin executing instructions.