Page of GC20-1807-7 As Updated April 1, 1981 by TNL GN25-0829
Invoking VMCF Subfunctions VMCF subfunctions are invoked by means of: • DIAGNOSE code X'68' subfunction codes • The VMCPARM parameter list • Extecnal interrupt code X'4001' • The external interrupt message header DIAGNOSE CODE X'68' All VKCF subfunctions are invoked from within assembler language
programs by means of DIAGNOSE code X'68': 83
Rx
Ry CODE <-------- 4 bytes ------->
83 I Rx I Ry , CODE is X'83' and interpreted by the assembler as the DIAGNOSE instruction. There is no mnemonic for DIAGNOSE. specifies a register containing the address of the VKCPARM parameter list.
is a register that contains a return code.
is X'0068' and specifies that you are requesting execution of
a VMCF. THE VMCPARM PARAMETER LIST The Rx reqister of DIAGNOSE X'68' contains the address of a parameter
list (VKCPARM). This parameter list is used to specify the VKCF subfunction to be executed, along with other information required by VKCF to execute that function. The address of VMCPARK must be
doubleword-aligned. The following is the format of the VKCPARM parameter list and a description of each of the fields in that list. Part 2. Control Program (CP) 159

Apr il 1, 1981 0 r- I V*1 I V*2 I VMCPFUNC VMCPMID 8 I I VMCPUSER 10 I- I VMCPVADA VMCPLENA 18 I , VliCPVADB VMCPLENB 20 I , VMCPUSE 28 L- V* 1 (VMCPFLG1 )
is a flaq byte used to specify options associated with a
particular subfunction.
This flaq byte can be set to the following values: VMCPAUTS (X'SO') Indicates, for the AUTHORIZE subfunction, an AUTHORIZE SPECIFIC request. When this bit is set, the VMCPUSER field
must contain the userid of the sink virtual machine. The
status of the specified sink virtual machine is not checked by the control program (CP) at this time. VMCPPRTY (X'40') Indicates, for SEND, SEND/RECV, SENDX, and IDENTIFY requests, a PRIORITY message request. For an AUTHORIZE request, it indicates an AUTHORIZE PRIORITY request. You cannot send PRIORITY messages to another virtual machine
unless that virtual machine has been authorized for PRIORITY messages. The SEND and RESPONSE external
interrupts for a PRIORITY' message are queued ahead of
pending nonpriority external interrupts. VMCPSMSG (X'20') Indicates that the virtual machine will accept messages
sent via the SMSG command.
Bits 3 through 7 are reserved for IBM use.
160 IBM System programmer's Guide