Table of Contents
Advertisement
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:
Advertisement
Table of Contents
