HP 32SII - Manual (Page 39)

The Automatic Memory Stack 2–1
File name 32sii-Manual-E-0424
Printed Date : 2003/4/24 Size : 17.7 x 25.2 cm
2
The Automatic Memory Stack
This chapter explains how calculations take place in the automatic memory
stack. You do not need to read and understand this material to use the
calculator, but understanding the material will greatly enhance your use of the
calculator, especially when programming.
In part 2, "Programming", you will learn how the stack can help you to
manipulate and organize data for programs.
What the Stack Is
Automatic storage of intermediate results is the reason that the HP 32SII easily
processes complex calculations, and does so without parentheses. The key to
automatic storage is the automatic, RPN memory stack.
HP's operating logic is based on an unambiguous, parentheses–free
mathematical logic known as "Polish Notation," developed by the Polish
logician Jan
Ł ukasiewicz (1878–1956).
While conventional algebraic notation places the operators between the
relevant numbers or variables,
Ł hukasiewicz's notation places them before
the numbers or variables. For optimal efficiency of the stack, we have
modified that notation to specify the operators after the numbers. Hence the
term Reverse Polish Notation, or RPN.
The stack consists of four storage locations, called registers, which are
"stacked" on top of each other. These registers—labeled X, Y, Z, and T–store
and manipulate four current numbers. The "oldest" number is stored in the T–
(top) register. The stack is the work area for calculations.