Hp 12C Financial calculator User Manual download pdf (Page 170)

170

File name: hp 12c_user's guide_English_HDPMBF12E44 Page: 170 of 209

Printered Date: 2005/7/29 Dimension: 14.8 cm x 21 cm

Appendix A

The Automatic Memory Stack

Four special re

isters in the hp 12c are used for storin

numbers durin

calculations. To understand how these

isters are used, they should be visualized as stacked on

top of each other.

(For this reason, they are

enerally referred to as the “stack re

isters” or

collectively as “the stack.”) The stack registers are designated X, Y, Z, and T.

Unless the calculator is in Program mode, the number shown in the display is the

number in the X-register (modified according to the current display format).

The number in the X-register — and, for two-number functions, the number in the

Y-register — are the number(s) used in calculations. The Z- and T-registers are used

primarily for the automatic retention of intermediate results during chain

calculations, as described in section 1.

Before we discuss the details of the stack operation, let’s take a quick look at how

the stack is used in a simple arithmetic calculation and in a chain calculation. For

each key pressed in the keystroke sequence, the diagram illustrating the

calculation shows, above the key, the numbers in each of the stack registers after

that key is pressed.

First, let’s consider the calculation of 5 – 2:

The diagram shows why we said in section 1 that the

key separates the

second number entered from the first number entered. Note also that this positions

the 5 in the Y-register above the 2 in the X-register — just like they would be

positioned if you wrote the calculation vertically on paper:

1 2 ... 165 166 167 168 169 170 171 172 173 174 175 ... 210 211

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Hp 12C Financial calculator User Manual Page 170