HP HP-35 - The Operational Stack

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THE OPERATIONAL STACK
To do the last examples your HP-35 had to save some
answers for future use. Let's see how it does this. There
are four number registers in the HP-35, which we call the
X, Y, Z and T regIsters. They are arranged in what is
called a "stock", X on the bottom and T on the top. The
display always shows the
number in the X register.
OPERATIONAL STACK
,
y
x
___ T Register
___ Z Re gi st er
___ Y RegIs ter
X Re gi st er
NOTE
The x Register is
~Iw~y~ rli~nl~Yflrl
To avoid confusion be-
tween the
name of a
register
and the number
in it, we designate the
register
by a capital
lener and t he number
by italics. Thus, X, y, Z
and I are the contents
n/X,Y,7~"dT
When you key in 11 number , it goos into the X register,
Which
is the only one displayed. When you press
IlDEiD ,this numbe r is repeated into the Y registe r. At
the same time, the
y is moved up to Z arxl z is moved up
to T like this:
When
you press a , Xisadded toy, and the whole stack
drops to d,splay the answer In X. The same Ihinghappeos
for = ' EI and G Whenell(!r the stack drops, I is
duplicated i nto T and Z, and Z drops 10 Y.
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