HP·38E/38C - Slide Rule Museum

100/101 Writing a Second Program
Overflow Calculations. Your calculator has been designed so that you
can always tell why the calculator stops by looking at the display.
If program execution stops because the result of a calculation in the
X-register is a number with a magnitude greater than 9.999999999 x
10 99 , all 9's are displayed with appropriate sign. It is then easy to
determine the operation that caused the overflow by toggling to program
mode and identifying the keycode in the display.
If the overflow occurs in one of the storage registers , possibly the result
of storage register arithmetic or the summation with CEl , the calculator
will display Error 1 to inform you of the overflow. Check the storage
registers to see in which register the overflow has occurred.
Error Stops. If the calculator attempts to execute any error-causing
operation during a running program, execution immediately halts and the
calculator displays Error and a number from 1 to 8. Press any key to
clear the error message (the function is not executed) and toggle into
program mode to see the line and key code of the error-causing
instruction. Don't forget, when you toggle back into run mode, you'll
be back at line 00.