EasyManuals Logo

IBM 7090 User Manual

IBM 7090
190 pages
To Next Page IconTo Next Page
To Next Page IconTo Next Page
To Previous Page IconTo Previous Page
To Previous Page IconTo Previous Page
Page #124 background imageLoading...
Page #124 background image
Transfer
on
Index
Low
or
Equal
TXL
-3000
(I, L)
Figure
5.3-60
If
the
number
in
the
specified
index
register
is
greater
than
the
decrement,
the
computer
takes
the
next
instruction
in
sequence.
If
the
number
in
the
index
register
is
equal
to
or
less
than
the
decrement,
an
instruction
transfer
will
be
taken
to
storage
location
X.
Execution
of
this
instruction
is
identical
to
that
of TNX
except
that,
because
no
reduction
is
required,
the
adders
will
not
be
routed
to
the
index
register.
Transfer
and
Set
Index
TSX +0074 (I, L)
Figure
5.3-61
This
instruction
places
the
2's
complement
of
the
instruction
counter
(the
location
of
the
TSX
instruction)
in
the
specified
index
register
and
causes
an
instruction
transfer
to
storage
location
X.
Execution
of
this
instruction
requires,
in
addition
to
the
normal
transfer
controls,
the
routing
of
the
instruction
counter
to
the
index
register.
This
involves
use
of
the
address
switch,
storage
register,
and
adders.
To
obtain
the
re-
quired
2
's
complement,
the
index
register
contents
must
also
be
cycled
through
the
adders
after
receiving
the
contents
of
the
instruction
counter.
Place
Addre
ss
in
Index
PAX
+0734
(1)
Figure
5.3-62
This
instruction
places
the
contents
of
AC
(21-35)
in
the
specified
index
register
in
true
form.
To
shift
the
address
field
to
the
decrement
positions
of
the
adders,
AC
(21-35)
is
routed
through
the
SR
to
AD(P-17).
Place
Decrement
in
Index
PDX
-0734
(1)
Figure
5.3-62
This
instruction
places
the
true
contents
of AC(3-17)
in
the
specified
index
register.
Because
no
shift
is
required
to
execute
this
instruction,
AC(3-17)
is
sent
to
AD(3-17)
through
the
SR.
Place
Complement
of
Address
in
Index
PAC
+0737
(I)
Figure
5.
3-62
This
instruction
places
the
2's
complement
of AC(21-35)
in
the
specified
index
register.
The
AC
is
unchanged.
The
complementing
is
accomplished
by
putting
the
address
in
the
XR
and
then
cycling
the
XR
through
the
adders.
Place
Complement
of
Decrement
in
Index
PDC
-0737
(1)
Figure
5.3-62
This
instruction
loads
the
2's
complement
of
AC(3-17)
in
the
specified
index
register.
The
AC
is
unchanged.
The
complementing
is
accomplished
in
the
same
manner
as
in
PAC.
Place
Index
in
Address
PXA +0754
(1)
Figure
5.3-63
This
instruction
places
the
true
contents
of
the
specified
index
register
in
AC
(21-35).
Positions
(S,
Q,
P-20)
of
the
AC
are
cleared.
To
obtain
the
true
contents
of
the
index
register
for
executing
this
instruction,
the
index
register
contents
are
cycled
through
the
adders.
The
index
register
contents
are
then
rerouted
to
the
adders
and
routed
to
the
storage
register
by
way
of
the
address
switch
to
shift
the
index
register
contents
to
the
address
field.
123

Table of Contents

Questions and Answers:

Question and Answer IconNeed help?

Do you have a question about the IBM 7090 and is the answer not in the manual?

IBM 7090 Specifications

General IconGeneral
CategoryMainframe Computer
Introduced1959
Transistor-basedYes
Word Length36 bits
Add Time4.8 microseconds
MemoryCore memory
Memory (words)32, 768 words