232 Appendix A: RPN and the Stack
File name: hp 12c pt_user's guide_English_HDPMF123E27 Page: 232 of 275
Printed Date: 2005/8/1
Dimension: 14.8 cm x 21 cm
When an arithmetic operation or
q
is performed, the answer is placed in the
X-register, the number formerly in the X-register is copied into the LAST X register,
and the stack
drops
. When the stack drops, the number in the Z-register is copied
into the Y-register, and the number in the T-register is copied into the Z-register
but
also
remains in the T-register.
The diagram on the next page illustrates the stack operation when 8 ÷ 2 is
calculated. (Assume that the stack and LAST X registers have already been loaded
with the numbers shown as the result of previous calculations.)
Percentage Functions
When any of the three percentage functions is performed, the answer is placed in
the X-register, the number formerly in the X-register is copied into the LAST X
register, but the stack does not drop. The numbers in the Y-, Z-, and T-registers are
not changed when a percentage function is performed.