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IBM 7090 User Manual

IBM 7090
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Accumulator
Right
Shift
ARS +0771 (I, L
•••
)
Figure
5.3-11
This
instruction
causes
the
contents
of
AC (Q-35)
to
be
shifted
right
the
number
of
places
indicated
by
the
address.
Bits
shifted
away
from
Q
are
replaced
by
zeros;
bits
shifted
past
position
(35)
are
lost.
ARS
is
similar
to
ALS
except
for
direction
of
the
shifting.
Long
Right
Shift
LRS +0765 (I, L
...
)
Figure
5.3-12
The
contents
of
the
MQ
and
AC
(except
the
sign
positions)
are
shifted
right
the
number
of
places
indicated
by
the
address.
The
MQ
sign
is
set
to
agree
with
the
AC
sign.
Bits
shifted
away
from
Q
are
replaced
by
zeros
and
shifted
past
AC(35)
enter
MQ(1).
Bits
shifted
past
MQ(35)
are
lost.
Logical
Right
Shift
LGR
-0765
(I, L
...
)
Figure
5.
3-12
This
instruction
shifts
the
contents
of
the
AC(Q-35)
and
MQ(S-35)
right
the
number
of
places
designated
by
the
address.
Bits
shifted
out
of
AC(35)
are
entered
into
MQ(S)
and
from
MQ(S)
to
MQ(1).
Bits
shifted
past
MQ(35)
are
lost.
The
operation
of
LGR
is
the
same
as
LRS
except
for
the
handling
of
the
MQ
sign.
Rotate
MQ
Left
RQL
-0773
(I, L
•..
)
Figure
5.3-13
This
instruction
shifts
the
contents
of
the
MQ,
including
the
sign,
left
the
number
of
places
designated
by
the
address.
Bits
shifted
out
of
MQ(l)
enter
the
sign
position
and
from
the
sign
position
enter
MQ(35).
5.3.03
Fixed-Point
Arithmetic
Instructions
Fixed-point
arithmetic
instructions
are
the
basic
calculating
instructions.
Addition
is
the
foundation
of
all
of
these
instructions,
and
parts
of
the
ADD
instruction
will
be
found
in
all
instructions.
All
arithmetic
instructions
use
the
accumulator.
Clear
and
Add
CLA
+0500 (I, E)
Figure
5.3-14
The
instruction
clears
the
AC
(S,
Q-35)
and
loads
positions
(S,
1-35)
with
the
con-
tents
of
the
storage
location
indicated
by
the
address.
The
word
that
is
to
be
put
into
the
AC
is
brought
from
core
storage
to
the
SR
during
the
E
cycle.
In
the
I
cycle
of
the
next
instruction,
positions
(1-35)
are
gated
from
the
SR
through
the
AD
to
the
AC.
The
sign
position
is
gated
directly
from
the
SR
to
the
AC.
Clear
and
Subtract
CLS
+0502 (I, E)
Figure
5.3-14
This
instruction
replaces
the
contents
of
the
AC
with
the
word
from
the
core
storage
location
indicated
by
the
address.
The
sign
of
the
word
is
reversed.
Execution
of
this
instruction
is
the
same
as
the
CLA
except
that
the
sign
of
the
word
is
inverted
during
the
E
cycle
after
the
word
has
entered
the
SR.
55

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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