The PURGESYS Function
The FINDSYS Function
When you save a named segment that is later loaded by the LOADSYS function,
you must be sure that the addresses at which segments are saved are correct and
that they do not overlay required areas of storage in the virtual machine. This is
crucial because the LOADSYS function invokes the PURGESYS function before it
builds the new page and swap tables. CP purges all saved systems that are over­
layed in any way by the saved system it is loading.
Condition Codes: A condition code of 0 in the PSW indicates that the named seg­
ment was loaded successfully; the Rx register contains the load address.
A condition code of 1 in the PSW indicates the named segment was loaded success­
fully within the defined storage of the virtual machine. The Rx register contains
the address at which the named segment was loaded. The Ry register contains the
ending address of the storage released before the named segment was loaded.
Note: CMS only allows named segments to be attached beyond the defined size of
the virtual machine. A condition code of 2 in the PSW indicates the LOADSYS function did not execute successfully. Examine the return code in the Ry register
to determine the cause of the error.
Return Code
44
177
Meaning
Named segment does not exist Paging 110 errors
When the PURGESYS function is executed; CP releases the storage, and associ­
ated page and swap tables, that were acquired when the corresponding LOADSYS function was executed. If the storage occupied by the named segment was beyond
the defined virtual machine storage size, that storage is no longer addressable by
the virtual machine.
When a PURGESYS function is executed for a segment that was loaded in non­
shared mode, the storage area is cleared to binary zeros. If PURGESYS is invoked
for a named segment that was not previously loaded via LOADSYS, the request is
ignored.
Condition Codes: A condition code of 0 in the PSW indicates successful
completion.
A condition code of 1 in the PSW indicates that the named segment was not found
in the virtual machine.
A condition code of 2 in the PSW and a return code of 44 in the Ry register indi­
cate that the named segment either does not exist or was not previously loaded via
the LOADSYS function.
When the FINDSYS function is executed, CP checks that the named segment exists
and that it has not been loaded previously.
Condition Codes: A condition code of 0 in the PSW indicates that the named seg­
ment is already loaded. The address at which it was loaded is returned in the regis­
ter specified as Rx and its highest address is returned in the Ry register. DIAGNOSE Instruction in a Virtual Machine 255

A condition code of 1 in the PSW indicates that the named segment exists but has
not been loaded. In this case, the address at which the named segment is to be
loaded is returned in the register specified as Rx and the highest address of the
named segment is returned in the Ry register.
A condition code of 2 in the PSW indicates the FINDSYS function did not execute
successfully. Examine the return code in the Ry register to determine the error that
occurred.
Return Code
44
177
Meaning
Named segment does not exist Paging 110 errors DIAGNOSE Code X'68' --Virtual Machine Communication Facility (VMCF) Privilege class G
The DIAGNOSE Code X'68' is used by a virtual machine to initiate a sub function
of the Virtual Machine Communication Facility (VMCF).
Entry Values: The general register specified as Rx contains the virtual address,
doubleword aligned, of a parameter list (VMCP ARM). One of the entries in this
parameter list is a subfunction code, specifying the particular request being
initiated. The sub functions and their codes are:
Subfunction AUTHORIZE UNAUTHORIZE SEND SEND/RECV SENDX RECEIVE
CANCEL
REPLY QUIESCE RESUME IDENTIFY
REJECT
Code X'OOOO' X'OOOl' X'0002' X'0003' X'0004' X'OOOS' X'0006' X'0007' X'0008' X'0009' X'OOOA' X'OOOB' A description of all the fields of the VMCPARM is contained in the section "Virtual Machine Communication Facility." The general purpose register specified as the Rx register contains the address of the VMCP ARM list.
The general register specified as Ry contains the return code upon completion of DIAGNOSE X'68' or the detection of an error condition. The return codes are
contained in the section "Virtual Machine Communication Facility." Rx and Ry can be any general register, RO through R1S. They may also be the
same register.
256 VM/SP System Programmer's Guide