The Last X Register And The Fkey; Chain Calculations In Rpn Mode - HP 12C Platinum Owner's Handbook Manual

172 Appendix A: RPN and the Stack
The LAST X Register and the
The number in the displayed X-register is copied into the LAST X register when-
ever any of the following function keys is pressed:
+ -
q >
T Ñ
R e
D Ò
Pressing gF lifts the stack (unless \, O, _, ^, A, or C was
the last key pressed, as described on page 168), then copies the number from the
LAST X register into the displayed X-register. The number remains also in the
LAST X register.
ey

Chain Calculations in RPN Mode

The automatic stack lift and stack drop make it possible to do chain calculations
without the necessity for keying in parentheses or storing intermediate results, as
are required on some other calculators. An intermediate result in the displayed
X-register is automatically copied into the Y-register when a number is keyed in
after a function key is pressed.
then pressed, that function is performed using the number keyed into the dis-
played X-register and the intermediate result in the Y-register. The number then
in the Y-register, if remaining as an intermediate result from an earlier calcula-
tion, can then be used with the intermediate result in the X-register for another
calculation.
2.
Except for \, O, _, ^, A, C, and – under certain circumstances – n, ¼,
$, P, and M. For more information, refer to Stack Lift, page 168.
KEY
F
§ z
¿ r
_ ^
b à
lost
2
Therefore, when a two-number function key is
y
B
Q
Z