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Xerox 560 Reference Manual

Xerox 560
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MASTER
MODE
The
master/slave
control
bit
(bit
8
of
the
PSWs) must
con-
tain
a
zero
for
the
basic
processor
to
operate
in
master
mode.
In th
is
mode
the
basic
processor
can
perform a
II
of
its
control
functions
and
can
modify
any
part
of
the
system.
The
restrictions
upon
the
basic
processor1s
operations
in
this
mode
are
those
imposed
by
the
write
locks
on
certain
pro-
tected
parts
of
memory.
It
is assumed
that
there
is a
res-
ident
operating
system
(operating
in
the
master
mode)
that
controls
and
supports
the
operation
of
other
programs
(which
may
be
in
the
master,
master-protected,
or
slave
mode).
MASTER-PROTECTED
MODE
The
master-protected
mode
of
operation
provides
additional
protection
for
programs
that
operate
in
the
master
mode.
The
master-protected
mode
occurs
when
the
basic
processor
is
operating
in
the
master
mode
with
the
memory
map
in
effect
and
the
mode
altered
control
bit
(bit
61
of
the
PSWs) is
on.
In
this
mode
the
memory
protection
violation
trap
occurs
(location
X
I
40
I
,
with
CC4
=
1),
as
it
does
in
all
mapped
slave
programs,
if
a
program
makes
a
reference
to
a
virtual
page
to
which
access
is
prohibited
by
the
current
setting
of
the
access
protecti
on
codes.
SLAVE
MODE
The
slave
mode
of
operation
is
the
problem-solving
mode
of
the
basic
processor.
In
this
mode,
access
protection
codes
apply
to
the
slave
mode
program
if
mapping
is in
ef-
fect,
and
all
IIprivileged
II
operations
are
prohibited.
Priv-
ileged
operations
are
those
relating
to
input/output
and
to
changes
in
the
fundamental
control
state
of
the
basic
pro-
cessor.
All
privileged
operations
are
performed
in
the
master
or
master-protected
mode
by
a
group
of
privileged
instructions.
Any
attempt
by
a program
to
execute
a
priv-
ileged
instruction
whi
Ie
the
basic
processor
is in
the
slave
mode
results
in a
trap.
The
master/slave
mode
control
bit
(bit
8
of
the
PSWs)
can
be
changed
when
the
basic
processor
is
in
the
master
or
master-protected
mode.
Nevertheless,
a s!aVe mode program can
gain
direct
access to certai!1
ex-
ecutive
program
operations
by
means
of
CALL
instructions.
-
The
operations
avai
lable
through
CALL
instructions
are
es-
tablished
by
the
resident
operating
system.
MAPPED
MODE
Although
the
memory
map
is
located
in
the
Memory
Inter-
face
(MI),
it
functions
as
part
of
the
basic
processor.
The
basic
processor
communicates
with
memory
through
the
MI.
Mapping
is
effective
for
all
the
words
of
real
memory,
and
is
invoked
when
bit
9 (MM)
of
the
PSWs
contains
a
one.
Memory
mapping
generates
real
page
addresse:s from vir-tual
addresses.
The memory
map
can
be
loaded
with
either
11-bit
real
page
addresses
or
8-bit
real
page
addresses
by
meansofthe
MOVE
MEMORY
CONTROL
(MMC)
privileged
instruction
(see
Chapter
3,
"Control
Instructions
").
Eleven-
bit
real
page
addresses
are
always
provided
for in
the
map,
thus
if
8-bit
real
page
addresses
are
generated,
the
three
12 Basic Processor
high-order
bits
contain
zeros.
The memory
map
always
maps
17-bit
virtual
addresses
into
20-bit
real
addresses
(see
IIMemory Address
Control
II,
later
in this
chapter
for a
dis-
cussion
of
how
the
map
is
used).
UNMAPPED
MODE
When
the
basic
processor
is
operating
in
the
unmapped
mode,
there
is a
direct
one-to-one
relationship
between
the
effec-
tive
virtual
address
of
each
instruction
and
the
actual
ad-
dress used
to
access
main
memory.
(See
II
Rea I
Addressing
ll
,
later
in
this
chapter.)
INFORMATION
FORMAT
Nomenclature
associated
with
digital
information
within
the
computer
system is
based
on
functional
and/or
physical
at-
tributes.
A
"word"
may
be
either
a
32-bit
instruction
word
or
a
32-bit
data
word.
The
bit
positions
of
a word
are
numbered
from 0
through
31
as
follows:
A word
can
be
divided
into
two
16-bit
parts
(halfwords) in
wh
ich
the
bit
positions
are
numbered
from 0
through
15
as
follows:
A word
can
also
be
divided
into
four
8-bit
parts
(bytes)
in
which
the
bit
positions
are
numbered
0
through
7
as
follows:
Two words
can
be
combined
to
form a
64-bit
element
(a
doubleword)
in
which
the
bit
positions
are
numbered
0
through
63
as
follows:
I : Least
Signif~cant
word: I
n " "
"I~
~
'" '"
~
" "
,,1«
" "
,,:«
"
'"
"I"
,;
,.
,,'
~
" " "1M,, " "
In
fixed-point
binary
arithmetic
each
element
of
information
represents
nurneiical
data
as
a
signed
integer
(bit
0
repre-
sents
the
sign,
remaining
bits
represent
the
magnitude,
and
the
binary
point
is assumed
to
be
just
to
the
right
of
the
least
significant
or
righi-most
bit).
Negative
va
lues
are
represented
in two1s
complement
form.
Other
formats
re-
quired
for
floating-point
and
decimal
instructions
are
de-
scribed
in
Chapter
3.

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Xerox 560 Specifications

General IconGeneral
Print Resolution2400 x 2400 dpi
Monthly Duty CycleUp to 300, 000 pages
Duplex PrintingStandard
Operating System CompatibilityWindows, Mac OS, Linux
ConnectivityEthernet, USB
Paper SizeUp to 13 x 19.2 inches
TypeMultifunction Printer

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