SIMULATION NOTES Because CMS has its own file system and is a single-user system operating in a virtual machine with virtual storage, there are certain
restrictions for the simulated as function in CMS. For example, HIAFCHY options and options that are used only by OS multitasking systems are
ignored by CMS. Due to the design of the CMS loader, an XCTL from the explicitly
loaded phase, followed by a LINK by succeeding phases, may cause
unpredictable results.
Listed belcw are descriptions of all the OS macro functions that are
simulated by CMS as seen by the programmer. ImFlementation and program results that differ from those given in and Services and Macro Instructions are
stated. HIARCHY options and those-used--only-by-os-iultItaskIng-systems are ignored by CMS. Validity checking is not performed within the simulation routines. The entry point name in LINK, XCTL, and LOAD (SVC 6, 7, 8) must be a member name or alias in a TXTLIB directory unless the COMPSWT is set to on. If the COMPSWT is on r svr n: 7; specify a module name. This switch is turned on and off by using the COMPSWT macre. See the for
descriptions ef all CMS user macros. Macro-SVC No. xnAP=SvcO---- wAIT-SVCl POST-SVC2 EXIT/RETURN -SYC3 GETMAIN-SVC4 FREEMAIN-SYCS LINK-SVC6 leTL-SVC7 The TYPE option must be R or W; the V, I, and K
options are not supported. The BLKREF-ADDR must point
to an item number acquired by a NOTE macro. Other options associated with V, I, cr K are not supported.
All 0Ftions of
waits for the
specified ECBs. WAIT are supported.
completion bit to The be WAIT routine
set in the
All options of POST are supported. POST sets a
completion code and a completion bit in the specified ECB. Post ECB, execute end of task routines, release
phase storage, unchain and free latest request block,
and restore registers depending upon whether this is
an exit or return from a linked or an attached
routine.
\
All options of GETMAIN are supported except SP and HIARCHY, Which are ignored by CMS, and LC and LV, which will result in abnormal termination if used. GETMAIN gets blocks of free storage.
All options of FREEMAIN are supported except SP, which
is ignored by CMS, and L, which will result in abnormal termination if used. FREEMAIN frees blocks
of storage acquired by GETMAIN. The DCB and HIARCHY options are ignored by CMS. All
other options of LINK are supported. LINK loads the
specified program into storage (if necessary) and
passes control to the specified entry point.
The DCB and HIARCHY options are ignored by CMS. All
other options of XCTL are supported. XCTL loads the
specified program into storage (if necessary) and
passes control to the specified entry point.
2-38 VM/370 System Logic and Program Determination--Volume 2

Macro-SVC IE. LOAD=SVC8 GETPOOLI FREEPOOL DELETE-SVC9 GETMAIN/ FREEMAIN­ SYC10 TIME-SYC11 ABEND-SVC13 SPIE-SVC14 RESTORE-SYC17 ELDL-SVC18 FIND-SVC18 STOi-SYC21 The DCB and HIARCHY options are ignored by All
other options of LOAD are supported. LOAD loads the
specified program into storage (if necessary) and
returns the address of the specified entry point in
register zero. However, if the specified entry point
is not in core when SVC 8 is issued, and the
subroutine contains VCONs that cannot be resolved
within that TXTLIB member, CMS will attempt to resolve
these references, and may return another entry point
address. To insure a correct address in register zero,
the user should bring such subroutines into core
either by the eMS LOAD/INCLUDE commands or by a VCON in the user program.
All the options of GETPOOL and FREEPOOL are supported. GETPOOL constructs a buffer pool and stores the
address of a buffer pool control block in the DCB. FREEPOOL frees a buffer pool ccnstructed by GETPOOL. All the options of DELETE are supported. DELETE
decreases the use count by one and, if the result is
zero, frees the corresponding virtual storage. Code 4
is returned in register 15 if the phase is not found.
All the options of GETMAIN and FREEMAIN are supported except SP and HIARCHY, which are ignored by CMS. All the options of TIME except MIC are supported. TIME returns the time of day to the calling program.
The completion code parameter is supported. The parameter is not. If a STAB request is outstanding,
control is 1iven to the proper STAB routine. If a STAB routine is not outstanding, a message indicating
that an abend has occurred is printed on the terminal
along with the completion code.
All the options of SPIE are supported. The SPIE routine specifies interruption exit routines and program interruption types that yill cause the exit
routine to receive control.
The RESTORE routine in CMS is a NOP. It returns
control to the user.
BLDL is an effective NOP for LINKLIBs and JOSLIBs. For TXTLIBs and MACLIBs, item numbers are filled in
the TTR field of the BLDL list; the K, Z, and user
data fields, as described in Macro Instructions, are set to zeros. The "alias" bit of-the-c-fiela-Is-snpported, and the remaining bits in
the C field are set to zero.
All the options of FIND are supported. FIND sets the
read/write pointer to the item number of the specified
member.
All the options of STOW are supported. The "alias"
bit is supported, but the user data field is not
stored in the MACLIB directory since eMS MACLIBs do
not contain user data fields. CMS Introduction 2-39