HP HP-65 - Registers; Addressable Registers; Storing and Recalling Data

Section 2
Registers
In this section we will describe the use of the nine addressable
storage registers and the manipulation of information in the stack.
Also, to illustrate a use of the stack registers we will present a
manual solution to a problem of compound interest.
Addressable Registers
Registers R, R,, . . . , R, constitute the addressable registers.
Their respective contents are referred to as ry, I, . . . , I,. Opera-
tions refer to them by number. The registers are typically used
to accumulate sums or to store constants or intermediate results.
You can store the value of the stack’s X-register in any addres-
sable register, or you can recall the value in any addressable
register to the X-register. Additionally, you can store in any
register an arithmetic sum, difference, product, or quotient of
the contents of the given register and the X-register. For example,
if R; contains 100 and if X contains 70, you can store the dif-
ference (100 — 70 = 30) in R; simply by pressing STO = [5].
Storing and Recalling Data
To stere a number appearing in the display (whether the result
of a calculation or keystroke entry):
1. Press STO .
2. Press a number key [1] through [9] to specify in which of
the nine registers the number is to be stored.
If the selected storage register already has a number in it, the old
number will be overwritten by the new one. The value in X will
remain unchanged.
To recall a number previously stored in one of the nine addres-
sable memory registers:
1. Press RCL .
2. Press a number key ([1]through[9]) to specify which of
the nine registers the number is to be recalled from.
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