HP HP-67

Section 3
The Automatic Memory Stack
The Stack
Automatic storage of intermediate results is the reason that the HP-67
slides so easily through the most complex equations. And automatic
storage is made possible by the Hewlett-Packard automatic memory
stack.
Initial Display
When you first switch the calculator ON, the display shows
in RUN mode. This represents the contents of the
display or ‘‘X-register.”’
Set the W/PRGM-RUN switch wrrem l[[MIrun to RUN.
Switch the HP-67 OFF, then ON.
Basically, numbers are stored and manipulated in the machine
“‘registers.”’ Each number, no matter how few digits (e.g., 0, 1, or
5) or how many (e.g., 3. 141592654, -23.28362, or 2.87148907 X
10%7), occupies one entire register.
The displayed X-register, which is the only visible register, is one of
four registers inside the calculator that are positioned to form the
automatic memory stack. We label these registers X, Y, Z, and T.
They are ‘‘stacked” one on top of the other with the displayed
X-register on the bottom. When the calculator is switched ON, these
four registers are cleared to zero.
Name Register
0.00
0.00
0.00
0.00 Always displayed.
X
<N-H
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