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IBM 7090 User Manual

IBM 7090
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Development
of
Program
CONTENTS
OF ACCUMULATOR
1-5
6-11
12-17
-23 -29 -35
CAL
A(Clear
AC,
add
logical
word
A)~
1 3 4
5
8
9
1st
Add B
+6
9 5
9
3
(Unconverted
binary
sum)
=7
onv
CVR
1000,
0,
6
ARS 6
Series
of
Steps
within
CVR
Table
Next
C(AC)
Start
Table
C(-)
Start
Loc
30-35
Loc
Refer
1-5
C(-)
21-35
*@
+ 1000
- 1012
1
2
7
12
5
10 17
Count
= 5
17
+
1001 - 1018
8
1001 8
2
7
12
5
10
10
+
1001
- 1011
1
1001
1
8
2
7
12
5
5
+
1001 - 1006 6
1000
6
1
8
2 7
12
12
+
1000
- 1012
2 2 6
1
8
2
7
7
+
1001
- 1008
8 8
2
6
1
8
2
Count
=
zero:
if
Tag
=
1,
1000
~RA
SLW C
(Store
converted
BCD
sum
as
logical
word)
The
execution
of CVR
requires
one
L
cycle
to
set
the
count
in
the
shift
counter
and
to
calculate
the
initial
table
location.
The
instruction
is
completed
in
as
many
E
cycles
as
specified
by
the
count.
Convert
by
Replacement
from
MQ
CRQ
-0154
(Min
I,
L)
Figure
5.3-72
(Max
I,
L,
6E)
This
instruction
operates
on
the
MQ,
considered
to
be
composed
of
six
6-bit
repre-
sentations.
The
instruction
replaces
a
number
of
these
representations
equal
to
the
count
of
the
instruction,
with
the
contents
of
positions
(S-5) of a
like
number
of
words
from
storage.
The
location
of
the
first
of
these
storage
words
is
found
by
adding
the
contents
of MQ(S-5)
to
SR(21-35)
(intiallythe
instruction
address
portion).
Thewordstored
at
this
modified
location
is
brought
to
the
SR,
and
the
MQ
is
shifted
left
six
places.
Positions
(S-5) of
the
stored
word
are
placed
in
MQ(30-35),
and
the
location
of
the
next
storage
word
is
computed
by
again
adding
MQ(S-5)
to
SR(21-35)
which
is
now
the
ad-
dress
portion
of
the
previous
storage
word.
The
process
continues
until
the
required
number
of
replacements
have
been
made.
At
this
time
the
presence
of
a
tag
bit
in
position
20 of
the
instruction
will
cause
the
address
portion
of
the
final
storage
word
to
be
stored
in
index
register
A.
The
following
illustrates
the
use
and
operation
of
CRQ:
Prepare
a BCD
number
for
printing
be
replacing
leading
zeros
with
blanks:
Convert
BCD
number
007109
to
BL
BL
7109
Instructions
required
for
this
operation:
LDQ A (BCD
number
in
storage)
CRQ
6,0,
2000
(Convert
from
MQ)
STQ B
(Store
converted
number)
135
=4
=3
=2
=1
=0

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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