HP HP-67

The Automatic Memory Stack 55
Press @3 again and the stack contents are shifted...
...from this... ...to this.
T 1.00 T 2.00
Z 4.00 Z 1.00
Y 3.00 Y 4.00
X |200 Display. X |3.00 Display.
Press 3 twice more...and the stack shifts...
...through this... ...back to the start again.
T 3.00
Z 2.00
Y 1.00
X 4.00 Display. Display.
Once again the number is in the displayed X-register.
Four presses of (3 roll the stack down four times, returning the
contents of the stack to their original registers.
You can also manipulate the stack contents using (3 (roll up).
This key rolls the stack contents up instead of down, but it otherwise
operates in the same manner as [ RY).
Exchanging x and y
The
(x
exchange
y)
key
exchanges
the
contents
of
the
X-
and
the
Y-registers
without
affecting
the
Z-
and
T-registers.
If
you
press
0
with
data
intact
from
the
previous
example,
the
numbers
in
the X- and Y-registers will be changed...
...from this... ...to this.
T 4.00 T 4.00
Z 3.00 z 3.00
Y 2.00 ><: Y 1.00
Display. X 1.00 X 2.00 Display.