Advertisement
6
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
Regis
ter
___
Z
Regi ster
___
Y
RegIs
ter
X
Regi
ster
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 the number
by italics.
Thus,
X,
y,
Z
and
I
are
the
contents
n/X,Y,7~"dT
Wh
en
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
regis te
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
into T and Z, and
Z
drops 10
Y.
1
Advertisement
