HP HP-67

172 Interrupting Your Program
If you have a number of halts for data entries in a program, it may
be helpful to “‘identify’’ each step by recording a familiar number
into the program immediately before each instruction. When the
calculator then stops execution because of the instruction, you
can look at the displayed X-register to see the ‘‘identification
number’’ for the required data input at that point. For example, if
your program contained eight stops for data inputs, it might be helpful
to have the numbers 1 through 8 appear so that you would know which
input was required each time. (Don’t forget that the ‘‘identification
number’’ will be pushed up into the Y-register of the stack when
you key in a new number.)
Pausing in a Program
Pausing to View Output
As you know, a instruction in a program halts execution of the
program until is again pressed from the keyboard. There are
often times when you may want a running program to pause long
enough for you to write down or view an answer, and then resume
execution again automatically. On your HP-67, there are two
functions that are used to cause a running program to momentarily
pause, and )
3 (52), when encountered as an instruction by a running program,
halts the program and displays the contents of the X-register for about
5 seconds, plenty of time to write down the answer, in most cases. So
that you will know that the program has not stopped completely, the
~decimal point blinks eight times during the pause. When the pause is
completed, the program resumes execution automatically with the
next instruction in program memory. If you press any key during an
pause, program execution stops altogether.
a (pause), when encountered as an instruction by a running
program, halts the program and displays the contents of the X-register
for about 1 second. This type of pause is usually employed where you
want to monitor the operation of a program, but where the recording
of answers is not important. When the pause is completed, the
program resumes execution with the next instruction in program
memory. Unlike an pause, you can key in numbers or execute
i
functions from the keyboard during a
The following example illustrates the operation of both types of
pauses to view output.