Subcode X'0008' Rx = virtual address of a 12-doubleword buffer
Ry = virtual spool reader address
processing for subcode X'0008' is the same as for subcode 1'0004', except that only card-image input files are processed.
Note: For both subcode X'0004' and subcode 1'0008', the for.at
definition for a VK/370 SFBLOK can be found in the syste •• acro library. Subcode X'OOOC' Rx = file identifier of requested file
Ry = virtual spool reader address
The spool input chain is searched for the file specified. If it is
not found, cc=2 is set. If it is found, the file is aoved to the head
of the chain so that it will be the next file processed by any of the
other functions.
Subcode X'0010' Rx = new copy count for the active file
Ry = virtual spool reader address
The specified device is checked for an active file. If no file is
active, cc=2 is set. Otherwise, the copy COUNT for the file is set to
the specified value, with a .axi.u. of 255. If the specified count is
not positive, a specification exception is generated. If the count is
greater than 255, it is adjusted to module 256.
Subcode X'0014' Rx = start address of virtual fullpage buffer
Ry = virtual spool reader address
The specified device is checked for an active file. If no active file
is found, cc=2 is set. Otherwise, the VSPLCTL pointers are reset to the
beginning of the file.
Subcode X'0018' Rx = start address of virtual full page buffer
Ry = virtual spool reader address
CP Introduction 1-55

The specified device is checked for an active file. If no active file
is found, cc=2 is set. Otherwise, the file is backspaced one record and
the record is given to the user as in subcode 1'0000'. If the file is
already positioned at the first record, the first record is given to the
user. Subcode X'001C' Rx = virtual address of a 12-doubleword buffer
Ry = virtual spool reader address
Processing is the same as Subcode 1'0008', except
spool files, as identified by the SFBMON flag is
handled. Subcode 1'0020' Rx = start address of full page virtual buffer
Ry = virtual spool reader address
Processing is the same as Subcode X'OOOO', except
spool files, as identified by the SFBMON flag in
handled. Subcode X'OFFF' Rx = virtual address of a 252-byte buffer
Ry = spool file ID number that only monitor
SFBFLAG2, can be
that only monitor
SFBFLAG2, can be
If Ry is nonzero, the spool input chain is searched for a file with a
matching ID nu.ber: If none is found or if one is found that is owned
by a different virtual machine, cc=2 is set. The chain search is
continued from the file that was found, or from the anchor if Ry is
zero, for the next file owned by the caller, independent of file type,
class, INUSE flag, etc. If none is found, cc=1 is set. Otherwise, the SPBLOK and the first record of the file (generally, the TAG) are copied
to the caller's virtual storage buffer.
Input/output operations to a direct access device, of the type used by CMS, can be performed from a virtual machine using DIAGNOSE code X'18'. No I/O interrupts are returned by CP to the virtual machine; the DIAGNOSE instruction is completed only when the READ or WRITE com.ands associated with the DIAGNOSE are completed. The Rx register contains
the virtual device address of the direct access device. The Ry register
contains the address of a chain of CCWs. The CCW chain must be in a
standard format that CP expects when DIAGNOSE code X'18' is used, as
shown below. Register 15 must be loaded by the user with the number of
READs or WRITEs in the CCW chain.
1-56 IB! V8/370 System LogiC and Problem Deter.ination--Volu.e 1