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 #108 background imageLoading...
Page #108 background image
Beginning-of-Tape
Test
BTT
+0760
...
XXXX (I, L)
Figure
5.3-46
This
instruction
tests
the
status
of
the
beginning-of-tape
indicator
in
a
particular
data
channel.
Address
1000-10000
selects
data
channels
A-H
respectively.
If
the
beginning-of
-tape
indicator
for
the
selected
channel
has
been
turned
on
by
a
previous
instruction,
the
indicator
is
turned
off
and
the
computer
takes
the
next
instruction
in
sequence.
If
the
indicator
is
already
off,
the
computer
skips
the
next
instruction.
End-of-Tape
Test
ETT
-0760
.•.
XXXX (I, L)
Figure
5.3-46
This
instruction
uses
address
1000-10000
to
select
the
data
channel
in
which
the
end-of-tape
indicator
is
to
be
tested.
If
the
indicator
is
on,
it
is
turned
off
and
the
computer
takes
the
next
instruction
in
sequence.
If
the
indicator
is
off,
the
computer
skips
the
next
instruction.
5.
3.
08
Control
Instructions
Control
instructions
are
provided
so
the
programmer
may
change
the
problem
condi-
tions
or
service
the
computer.
Halt
and
Proceed
HPR
+0420 (I, L)
Figure
5.3-47
This
instruction
causes
the
computer
to
stop
at
the
end
of
I
time.
When
the
start
button
is
depressed,
the
computer
proceeds
to
the
next
instruction
in
sequence.
When
halted,
the
PC
contains
the
address
of
the
next
sequential
instruction.
Halt
and
Transfer
HTR
+0000 (I, L)
Figure
5.3-48
This
instruction
causes
the
computer
to
stop
at
the
end
of
1
time
by
turning
on
the
master
stop
trigger
at
110(D1).
Depressing
the
start
button
causes
the
computer
to
proceed
in
L
time
of a
transfer
operation
and
the
computer
takes
an
instruction
trans-
fer
to
location
X.
When
halted,
the
PC
contains
the
address
of
the
HTR
instruction.
No
Operation
NOP
+0761 (I, L)
The
NOP
instruction
performs
no
active
function,
but
is
used
to
reserve
space
for
other
instructions.
Since
this
instruction
has
a
primary
operation
76,
an
1
and
an
L
cycle
are
required.
The
only
function
of
this
instruction
is
to
turn
on
the
end
operation
trigger
to
allow
the
computer
to
proceed
to
1
time
of
the
next
sequential
instruction.
SOD
01
on
Systems
3.07.01.
1
causes
L END
OP
on
Systems
8.00.09.1.
Execute
XEC
+0522
(I)
Figure
5.3-49
This
instruction
causes
the
computer
to
perform
the
instruction
at
location
X.
The
program
counter
is
not
altered;
therefore,
after
the
instruction
at
location
X
has
been
executed,
the
computer
proceeds
to
the
next
sequential
instruction
(instruction
in
next
position
beyond
the
XEC
instruction).
XEC
prevents
AR
to
PC
on
Systems
3.06.05.1.
If
the
instruction
at
location
X
is
an
unconditional
transfer
or
a
successful
conditional
transfer,
the
computer
does
not
proceed
to
the
next
instruction
following
the
XEC,
but
proceeds
to
the
address
specified
by
the
transfer.
Another
exception
occurs
when
the
instruction
at
location
X
is
a
skip
type,
and
the
conditions
are
met
for
this
skip.
The
PC
is
stepped
and
the
skip
is
in
relation
to
the
location
of
the
XEC
instruction.
Set
Sign
Plus
SSP
+0760
•••
0003 (I, L)
Figure
5.3-50
This
instruction
places
a
zero
(a
plus)
in
the
accumulator
sign
position.
Positions
(Q-35)
of
the
accumulator
are
unchanged.
107

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