34 Section 3: The Memory Stack, LAST X, and Data Storage

shading indicates that the contents of that register will be written over when the next number is keyed in or recalled.)

 

 

 

lost

 

lost

 

 

 

lost

T

t

 

z

 

 

y

 

y

 

 

x

Z

z

 

y

 

 

x

 

x

 

1

 

Y

y

 

x

 

1

 

 

1

 

2

 

X

x

 

1

 

 

1

 

 

2

 

 

2

 

Keys:

1

 

v

2

v

 

 

 

 

 

 

lost

 

 

 

T

x

 

 

x

 

1

 

1

 

Z

1

 

 

1

 

2

 

2

 

Y

2

 

 

2

 

3

 

3

 

X

2

 

 

3

 

3

 

4

 

Keys:

 

3

 

 

v

 

4

 

 

)(roll down), ((roll up), and ®(X exchange Y). )and ( roll the contents of the stack registers up or down one register (one value moves between the X- and the T-register). No values are lost. ® exchanges the numbers in the X- and Y-registers. If the stack were loaded with the sequence 1, 2, 3, 4, the following shifts would result from pressing ))and ®.

T

1

 

4

 

1

 

1

Z

2

 

1

 

2

 

2

Y

3

 

2

 

3

 

4

X

4

 

3

 

4

 

3

Keys: )

®

(