HP·38E/38C - Slide Rule Museum

What Is a Program? 85
The illustration on the left shows the first IO lines of program memory
immediately after pressing (]] @ill in program mode or turning the
HP-38E on. The illustration on the right shows program memory after
recording the eight-line example program.
A [GTO I 00 instruction in the program tells the calculator to go to line 00
and execute the automatic stop instruction there next. If []ill is pressed
again in automatic run mode, the calculator will begin executing instructions
from line 00 as it did the first time. Each time the calculator
executes this program, it ends execution at line 00, ready to begin again.
If you had recorded a 99-line program, after executing line 99 the
calculator would go to line 00, the automatic stop instruction, and stop.
Then you would have to press []ill to execute the program again.
Now try an example.
Example: Calculate the discounted price plus sales tax of a lamp
marked $75 and an ottoman marked $115. (Remember, we are still
assuming a 25% discount.and 6% sales tax.)
Keystrokes
75 []ill
115 []ill
Display
59.63
91.43
Discounted price of lamp
pi us sales tax.
Discounted price of ottoman
pi us sales tax .
When you hold down the []ill key, the display will show the line where
program execution begins.
Each time you press []ill the calculator executes the sequence of
keystrokes you have recorded. You calculate the same answers you
would obtain if you did each problem manually, but without the time or
the tedium.
Automatic Memory Allocation
When you clear the calculator of previous programs, you have eight lines
of program memory available and 20 storage registers. The memory is