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Section 2: Registers 31
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keeping intermediate results in the stack above those being calculated. To lift information in the stack,
you have used ENTER and the automatic lift. To drop the stack, you have used the arithmetic functions.
We will now consider the three remaining operations to move information in the stack.
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R
Roll Up
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R
Roll Down
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x y
Exchange
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You use these operations to verify (display) the contents of stack registers other than X
and to move information into place for calculation.
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Notice that
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R allows you to conveniently see t.
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R saves x in the T-Register.
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x y allows you to look at y without altering t or z.
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R , R and x y are functions appearing on the 9, 8, and 7 keys.
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You may notice that R and x y are also available on the D and E keys when the power is first
turned on. The five functions shown in the window were selected because they are the most commonly used.
Their primary intent is for manual use from the keyboard, as in this case. They each permit single keystroke
operation of functions that otherwise would require two keystrokes. When the A , . . . , E keys are
redefined by a program, the window functions are still available by two keystrokes.
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