GENMOD CMS Nucleus command
Use the GENMOD command to generate a (MODULE) file on a CMS disk.
The format of the GENMOD command is:
+----------+------------------------------------------------------------------+
| GENMOD | [fn [MODULE [A1|fm]]] [(options... [)]] |
| | options: |
| | FROM entry1 TO entry2 MAP|NOMAP |
| | STR|NOSTR OS|DOS|ALL SYSTEM |
+----------+------------------------------------------------------------------+
where:
fn is the filename of the MODULE file being created. If fn is not
specified, the file created has a filename equal to that of the first
entry point in the LOAD MAP.
fm is the filemode of the MODULE file being created. If fm is not
specified, A1 is assumed.
Options:
If conflicting options are specified, the last one entered is used.
FROM entry1
specifies an entry point or a control section name that represents the
starting virtual storage location from which the nonrelocatable copy
is generated.
TO entry2
specifies an entry point or a control section name that represents the
ending virtual storage location from which the nonrelocatable copy is
generated.
MAP includes a load map in the MODULE file, which is an 80-byte record
placed in front of the load module. MAP is the default.
NOMAP specifies that a load map is not to be contained in the MODULE file.
Note: If a module is generated with the NOMAP option, that module
cannot later be loaded and started with the CMS LOADMOD and START
commands. When NOMAP is specified, the information produced is not
sufficient for the START command to execute properly. However, a
module generated with the NOMAP option can later be invoked as a
command; that is, it can be invoked if its filename is entered.
STR invokes the CMS storage initialization routine when the MODULE file is
subsequently loaded (using the LOADMOD command). This routine frees
any storage remaining from a previous program. STR is the default
setting if the MODULE is to be loaded at the beginning of available
user storage.
If you have issued CMS SET RELPAGE ON, STR causes CMS storage
initialization to release the remaining pages of storage.
Note: If a program running in the user area calls a transient
routine that was generated with the STR option, the user area storage
pointers will be reset. This reset condition could cause errors upon
return to the original program (for example, when OS GETMAIN/FREEMAIN
macros are issued in the user program).
NOSTR indicates that, when the MODULE is loaded, free storage pointers are
not reset for any storage currently in use. NOSTR is the default
setting if the MODULE file is to be loaded at a location other than
the default load address.
SYSTEM indicates that when the MODULE file is subsequently loaded, it is to
have a storage protect key of zero.
OS indicates that the program may contain OS macros and, therefore,
should be executed only when CMS/DOS is not active.
DOS indicates that the program contains VSE macros; CMS/DOS must be active
(that is, SET DOS ON must have been previously invoked) in order for
this program to execute. (See Usage Note 2).
ALL indicates that the program:
o Contains CMS macros and must be capable of running regardless of
whether or not CMS/DOS is active.
o Contains no VSE or OS macros.
o Preserves and resets the DOS flag in the CMS nucleus.
o Does its own setting of the DOS flags.
Note: The ALL option is primarily for use by CMS system programmers.
CMS system routines are aware of which environment is active and will
preserve and reset the DOS flag in the CMS nucleus.
Usage Notes:
1. The GENMOD command is usually invoked following the LOAD command, and
possibly the INCLUDE command. For example, the sequence:
load myprog
genmod testprog
loads the file MYPROG TEXT into virtual storage and creates a
nonrelocatable load module named TESTPROG MODULE. TESTPROG may now be
invoked as a user-written command from the CMS environment.
2. The execution of MODULE files created from DOS programs is not supported
and may give unpredictable results. GENMOD is intended for use with the
LOAD command, not the FETCH command. Storage initialization for FETCH is
different from that for LOAD.
3. Before the file is written, undefined symbols are set to location zero and
the common reference control section is initialized. The undefined symbols
are not retained as unresolved symbols in the MODULE file. Therefore, once
the MODULE file is generated, those references cannot be resolved and may
cause unpredictable results during execution.
4. If you load a program into the transient area you should issue the GENMOD
command with the STR option. Be careful if the program uses OS GETMAIN or
FREEMAIN macros because your program, plus the amount of storage obtained
via GETMAIN, cannot exceed two pages (8192 bytes). It is recommended that
you do not use GETMAIN macros in programs that execute in the transient
area.
5. A transient module (loaded with the ORIGIN TRANS option) that was generated
with the SYSTEM option is written on disk as a fixed-length record with a
maximum length of 8192 bytes. The relocation and history information for
these files cannot be saved.
6. If you are using FORTRAN under CMS, compiling with the RENT option, and
have named the main program the same as fn, then you must use the FROM
option specifying entry1 the same as fn, preceded by an "at" sign (@).
For example, you would enter:
genmod mnprog (from @mnprog
7. If FROM is not specified on the GENMOD command, the starting virtual
storage location (entry point) of the module is either the address of fn
(if it is an external name) or the entry point determined according to the
hierarchy discussed in Usage Note 4 of the LOAD command. This is not
necessarily the lowest address loaded. If you have any external references
before your START or CSECT instructions, you must specify the 'FROM entry1'
operand on the GENMOD command to load your program properly. External
references include the following: EXTRN, WXTRM, DXD, CXD, and COM are
considered EXTERNAL references. The Assembler Language Reference and
Programmers Guide should be consulted for additional information on
external references.
8. If you are using PL/I under CMS, use FROM PLISTART as an option to avoid
unpredictable results.
9. The GENMOD command can be used to create a relocatable CMS MODULE file.
Relocation is performed only when using the NUCXLOAD command. When the
GENMOD command generates a MODULE file, one record of this MODULE file can
contain relocation information. This depends on the previous LOAD or
INCLUDE command that was issued. If the RLDSAVE option was specified on
the LOAD or INCLUDE command, the MODULE file may contain the relocation
information. If the RLDSAVE option was not specified on the LOAD or
INCLUDE command, the relocation information for the file cannot be saved
See the LOAD or INCLUDE commands for more information.
10. The FROM or TO options should not be specified when module relocation
information is being saved (using RLDSAVE option of the LOAD and INCLUDE
commands). If specified, the results will be unpredictable. The FROM or TO
options must not be specified if module is loaded into the Transient area
since the start address must be X'E000'.
11. If the HIST option was specified on the LOAD or INCLUDE command, the module
file may contain history information. See the LOAD or INCLUDE commands for
more information.