HP 15c - Manual (Page 42)

42 Section 3: The Memory Stack, LAST X, and Data Storage
Keystrokes Display
* 1,150.0000 Population at the end of day 1.
* 1,322.5000 Day 2.
* 1,520.8750 Day 3.
* 1,749.0063 Day 4.
Storage Register Operations
When numbers are stored or recalled, they are copied between the display
(X-register) and the data storage registers. At ―power-up‖ (initial turn-on or
Continuous Memory reset) the HP-15C has 21 directly accessible storage
registers: R
0
through R
9
, R
.0
through R
.9
, and the Index register (R
I
) (see the
diagram of the registers on the inside back cover). Six registers, R
2
to R
7
,
are also used for statistics calculations.
The number of available data storage registers can be increased or
decreased. The m
function, which is used to reallocate registers in
calculator memory, is discussed in appendix C, Memory Allocation. The
lowest-numbered registers are the last to be deallocated from data storage,
therefore it is wisest to store data in the lowest-numbered registers
available.
Storing and Recalling Numbers
O (store). When followed by a storage register address (0 through 9 or
.0 through .9*), this function copies a number from the display (X-register)
into the specified data storage register. It will replace any existing contents
of that register.
l
(recall). Similarly, you can recall data from a particular register into
the display by pressing l followed by the register address. This brings
a copy of the desired data into the display; the contents of the storage
register remain unaltered.
X (X exchange). Followed by 0 through .9, *
this function exchanges the
contents of the X-register and the addressed data storage register. This is
useful to view storage registers without disturbing the stack.
* All storage register operations can also be performed with the Index register (using V or %), which is
covered in section 10, and with matrices, section 12.