HP HP-67 - Page 68

64 The Automatic Memory Stack
In addition to the automatic stack lift after a calculation, the stack
automatically drops during calculations involving both X- and Y-
registers. It happened in the above example, but let’s do the prob-
lems differently to see this feature more clearly. For clarity, first
press to clear the X-register. Now, again solve 16 + 30 + 11
+17 =7
Press Stack Contents
16 T o0.00
0.00 16 is keyed into the
0.00 displayed X-register.
16.
—
X
<
N
0.00
0.00
16.00
16.00
16 is copied into Y.
X
< N -
30 0.00
0.00 30 is written over
16.00 the 16 in X.
30. X < N —
0.00
16.00 30 is entered into Y.
30.00 16 is lifted up to Z.
30.00 X
<
N o
0.00
16.00 11 is keyed into the
30.00 displayed register.
11
11
X<
N-H
16.00
30.00
11.00
11.00
11 is copied into Y. 16
and 30 are lifted up to T
and Z respectively.
X
<
NH