XDAP
PROGRAMMING
SPECIFICATIONS
MACRO-INSTRUCTIONS
When
you
are
using
the
XDAP
macro-instruction,
you
must
also
issue
DCB, OPEN, CLOSE,
and,
in
some
cases,
the
EOV
macro-instruction.
The
parameters
of
the
XDAP
macro-instruction
are
listed
and
described
here.
For
the
other
required
macro-instructions,
special
requirements
or
options
are
explained,
but
you
should
refer
to
the
"EXCP
Macro-Instruction"
section
of
this
publication
for
listings
of
their
parameters.
DCB
--
Define
Data
Control
Block
The
EXCP
form
of
the
DeB
macro-instruction
produces
a
data
control
block
that
can
be
used
with
the
XDAP
macro-instruction.
You
must
issue
a
DCB
macro-instruction
for
each
data
set
to
be
read
or
updated
by
the
direct-access
channel
program.
The
"EXCP
Macro-Instruction"
section
of
this
publication
contains
a
diagram
of
the
data
control
block,
as
well
as
a
listing
of
the
parameters
of
the
DCB
macro-instruction.
OPEN
--
Initialize
Data
Control
Block
The
OPEN
macro-instruction
initializes
one
or
more
data
control
blocks
so
that
their
associated
data
sets
can
be
processed.
You
must
issue
OPEN
for
all
data
control
blocks
that
are
to
be
used
by
the
direct
access
program.
Sonte
of
the
procedures
performed
when
OPEN
is
executed
are:
•
Construction
of
data
extent
block
(DEB).
•
Transfer
of
information
from
DD
statements
and
data
set
labels
to
data
control
block.
•
Verification
or
creation
of
standard
labels.
•
Loading
of
programrr.er-written
appendage
routines.
The
two
parameters
of
the
OPEN
macro-instruction
are
the
addressees)
of
the
data
control
block(s)
to
be
initialized,
and
the
intended
method
of
I/O
processing
of
the
data
set.
The
method
of
processing
may
be
specified
as
either
INPUT
or
OUTPUT;
however,
if
neither
is
specified,
INPUT
is
assumed.
XDAP
--
Execute
Direct-Access
Prograrr
The
XDAP
macro-instruction
produces
the
XDAP
control
block
(i.e.,
the
ECB,
lOB,
and
channel
program)
and
executes
the
direct-access
channel
program.
The
format
of
the
XDAP
macro-instruction
is:
r-----------T----------------------------------------------------------,
I
Operation
I
Operand
I
.-----------+----------------------------------------------------------~
I
XDAP
I
ecb-symbol,type-{RIWIV}{IIK},dcb-addr,area-addr
I
I
I
,length-value,[(key-addr,keylength-value)],blkref-addr
I
L
___________
L
__________________________________________________________
J
ecb-symbol
specifies
the
symbolic
name
to
be
assigned
to
the
XDAP
control
block.
type-{RIWIV}{IIK}
100
specifies
the
type
of
I/O
operation
intended
for
the
data
set
and
the
method
by
which
blocks
of
the
data
set
are
to
be
located.
The
codes
and
their
meanings
are
as
follows:
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