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IBM 7090 User Manual

IBM 7090
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Store
Decrement
STD +0622 (I, E)
Figure
5.3-2
The
contents
of
AC(3-17)
replace
the
contents
of
positions
(3-17) of
core
storage
lo-
cation
X.
The
remaining
storage
positions
are
unchanged,
and
the
AC
is
unchanged.
This
instruction
operates
similarly
to
store
prefix,
except
that
MF
store
decrement
rather
than
MF
store
prefix
is
made
active.
Store
Tag
STT
+0625 (I,
E)
Figure
5.3-2
The
contents
of AC(18-20)
replace
the
contents
of
positions
(18-20) of
core
storage
location
X.
The
AC
and
the
remaining
positions
of
core
storage
are
unchanged.
This
instruction
operates
similarly
to
store
prefix,
except
that
MF
store
tag
rather
than
MF
store
prefix
is
made
active.
Store
Address
ST
A +0621 (I,
E)
Figure
5.3-2
The
contents
of AC(21-35)
replace
the
contents
of
positions
(21-35) of
core
storage
location
X.
The
remaining
positions
of
storage
and
the
contents
of
the
AC
are
un-
changed.
This
instruction
also
operates
Similarly
to
store
prefix,
except
that
MF
store
address
rather
than
MF
store
prefix
is
made
active.
Store
Left
Half
MQ
SLQ
-0620
(1,
E)
Figure
5.3-3
The
contents
of
positions
(S-17) of
the
MQ
replace
the
contents
of
positions
(S-17) of
storage
location
X.
The
remaining
storage
positions
and
the
contents
of
the
MQ
are
unchanged.
MF
store
prefix,
MF
store
decrement,
and
MF
store
control
lines
are
activated
so
SB(S-17)
can
be
read
into
storage.
The
word
is
sent
from
the
MQ
to
the
SR
so
it
can
be
put
on
the
SB.
Store
Instruction
Location
Counter
STL
-0625
(1,
E)
Figure
5.3-4
The
contents
of
the
program
counter,
which
contains
the
location
of
the
STL
instruc-
tion
plus
one,
replace
the
contents
of
positions
(21-35) of
storage
location
X.
The
contents
of
the
PC
and
the
remaining
positions
of
storage
are
unchanged.
The
MF
store
address
and
MF
store
control
lines
are
activated
so
the
address
portion
of
the
storage
word
can
be
changed.
The
PC
contents
are
sent
to
core
storage
on
the
SB.
The
con-
tents
of
the
PC
are
sent
to
the
SR
through
the
AS
and
the
output
of
the
SR
feeds
the
SB.
Load
MQ
LDQ +0560
(1,
E)
Figure
5.3-5
The
contents
of
the
MQ
are
replaced
by
the
contents
of
stor
age
location
X.
The
storage
word
is
put
into
the
SR,
and
the
output
of
the
SR
is
sent
to
the
MQ.
Exchange
AC
and
MQ
XCA +0131
(1)
Figure
5.3-6
The
contents
of
the
AC(S,
1-35)
are
interchanged
with
the
contents
of
the
MQ(S,1-35).
AC
positions
Q
and
P
are
reset.
The
SR
is
used
for
temporary
storage
while
routing
the
MQ
to
the
AC.
Exchange
Logical
Accumulator
and
MQ
XC
L
-0130
(I)
Figure
5.3-7
This
instruction
interchanges
the
contents
of
AC(P-35)
and
the
contents
of
the
MQ
(S-35).
Positions
(S)
and
(Q)
of
the
AC
are
cleared.
Execution
is
identical
to
that
of
XCA
except
for
the
handling
of
AC
positions
(S)
and
(P).
The
contents
of
the
MQ
are
put
into
the
SR.
The
contents
of
the
SR(S,
1-35)
and
the
AC
(P,
1-35)
are
interchanged,
putting
the
original
MQ
in
the
AC.
Gating
the
output
of
the
SR(S,
1-35)
to
the
MQ(S,
1-35)
places
the
original
AC
contents
in
the
MQ.
AC
positions
(Q)
and
(S)
are
cleared
because
of
normal
shift
cell
operations.
50

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IBM 7090 Specifications

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