230 Appendix A: RPN and the Stack

Termination of Digit Entry

The first digit keyed in after digit entry has been terminated replaces the number already in the displayed X-register. Digit entry is automatically terminated when any key is pressed (except for digit entry keys — digit keys, ., Þ, and É— and prefix keys — f, g, ?, :, and i).

Stack Lift

When the stack lifts, the number in each stack register is copied into the register above, and the number formerly in the T-register is lost. The number formerly in the X-register is then contained in both the X-register and the Y-register.

When a number is entered into the displayed X-register — either from the keyboard, from a storage register (using :), or from the LAST X register (using F) — the stack usually lifts first. The stack does not lift if the last key pressed before a number is entered was one of the following: \*, O, _ or ^. If one of these keys was the last key pressed, the number in the displayed X-register is replaced when a new number is entered.

Rearranging Numbers in the Stack

The Key

Pressing ~ exchanges the numbers in the X- and

Y-registers.

Certain functions (Ò, Ï, !, E, V, Ý, #, Ö, v, R, and Q) return answers to the Y-register as well as to the displayed X-register. The ~key, since it exchanges the number in the Y-register with that in the displayed X-register, is used to display the second number calculated.

The Key

When d (roll down) is pressed the number in each stack register is copied into the register below, and the number formerly in the X-register is copied into the T-register.

Pressing d four times successively displays the numbers in the Y-, Z-, and T-registers and returns the numbers to their original registers.

*Note also that although the stack lifts when \ is pressed, it does not lift when a number is entered after \is pressed.

File name: hp 12c pt_user's guide_English_HDPMF123E27

Page: 230 of 275

Printed Date: 2005/8/1

Dimension: 14.8 cm x 21 cm

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Image 230
HP 12C Financial 12C manual Rearranging Numbers in the Stack, Termination of Digit Entry, Stack Lift, Key