CP= (Used on ACCEPT, CONNECT, DESCRIBE, PURGE, QUIESCE, RECEIVE REJECT, REPLY, RESUME, RTRVBFR,
SEND, SEVER, TESTCMPL)
DATA=
Specify CP=NO when invoking an lUCY function from a virtual
machine. lUCY generates the IUCV instruction. The code gener­
ated when you specify CP=NO modifies general register zero. The
virtual machine must be in supervisor state when the lUCY macro
executes. CP= YES specifies that the function is being invoked from the CP system code. A CALL linkage to CP module DMKIUACP is gen­
erated instead of the lUCY instruction. The macro modifies gener­
al registers 0, 1, and 15. The invoker is responsible for providing an
EXTRN statement for module DMKIUACP. General register 11 is
assumed to contain the address of the VMBLOK on whose behalf
the specified function is to be performed. See the section "Com­ munication Between CP and a Virtual Machine" for details on IUCV communications initiated from CP system code.
The valid values for CP= are YES and NO. If not specified, the
default is NO. CP= YES is required to invoke lUCY functions from CP system
code.
If CP=YES is specified, MSGTAG= is not allowed.
The DESCRIBE and TEST COMPLETION functions cannot be
used in CP outside of lUCY support.
(Used on SEND, REPLY) This parameter specifies the location of your message data for this lUCY communication.
If you specify DATA=PRMMSG, your message or reply data is
contained in the parameter list. You may use the PRMMSG= parameter to have the message or reply data moved into the param­
eter list. When DATA= is specified, the lUCY macro parameters
BUFFER and BUFLEN may not be used on the SEND function
and the parameters ANSBUF and ANSLEN may not be used on the REPLY function.
If you specify DATA=BUFFER, your messages or reply is con­
tained in a buffer. The lUCY macro parameter of PRMMSG= may
not be used when DATA=BUFFER.
The DATA= option on SEND and REPLY are independent of each
other. The protocol used is at the discretion of the communicators.
You may define a protocol such that:
A message specified in the parameter list using the DAT A=
option is REPL Yed to via a message in the answer buffer speci­
fied on the SEND.
Inter-User Communications Vehicle 131

FCNCD= I MASK= A message sent in a buffer may be REPL Yed to by the target
via a message in the parameter list using the DAT A= option.
(Used on CONNECT) This parameter indicates which CP system service is invoking the CONNECT function. Each supported CP service is identified by a
one-byte numerical code. VM/SP presently supports IUCV com­
munication for only one CP Service, SNA Console Communication
Services. CCS has a code of O. Specify either the code itself or the number of a register that con­
tains the code in its low-order byte. IUCV moves the code into the
function parameter list.
If this parameter is not specified, the macro assumes that the
invoker has stored a value in the parameter list prior to invoking the IUCV macro.
This parameter is valid only if CP= YES is specified.
(Used on SETMASK and SETCMASK)
This parameter specifies the mask byte to determine which, if any,
of the IUCV external interrupts a virtual machine is to be enabled
for. Specify either the relocatable label of a byte containing the
mask, or the number of a register that contains the mask in its
low-order byte. IUCV moves the mask into the function parameter
list.
If this parameter is not specified, the macro assumes that the
invoker has stored a value in the parameter list prior to invoking the IUCV macro.
The MASK= parameter is valid only if you have specified CP.=NO. The SET MASK and SET CONTROL MASK functions cannot be
invoked from CP system code.
MF= (Used on ACCEPT, CONNECT, DCLBFR, DESCRIBE, PURGE, QUESCE, RECEIVE, REJECT, REPLY, RESUME, SEND,
SETMASK, SETCMASK, SEVER, TESTCMPL)
132 VM/SP System Programmer's Guide
The MF=L option is allowed as a keyword parameter on any IUCV function that uses a parameter list.
This paramater lets you initialize an IUCV parameter list without
issuing the IUCV instruction (from a virtual machine) or the SVC
(from CP system code). This parameter allows programs to initial­
ize an IUCV parameter list and to pass that parameter list to an
operating system which provides an IUCV interface (for example,
CMS).