IBM: MODHDCB

Programming Interface Information: This information is NOT intended to be
used as Programming Interfaces of VM/ESA. It is to be used for diagnosis only.

MODHDCB

Prolog

Control Block Contents

MODHDCB DSECT

Storage Layout

Cross Reference (Contains links to field and bit definitions)

MODHDCB Prolog
 Name       : MODHDCB
 Description: Module Header Control Block
 DSECT      : MODHDCB
 Notes      : This macro describes the first record,
              called the header record, in a CMS Module file.
              This header is 80 bytes long and exists in
              variable format record file system module files
              and all byte file system module files.

MODHDCB Control Block Content


MODHDCB DSECT
Hex   Dec Type/Val   Lng Label (dup)    Comments
---- ---- --------- ---- -------------- --------
0000    0 Structure      MODHDCB        Module Header Control Block
0000    0 Character   40 NUCONMAP       1st 40 bytes mapped by NUCON
0000    0 Signed       4 STARTADR       Start Location
0004    4 Signed       4 XFRSTLOC       Beginning location in storage
0008    8 Signed       4 XLASTLOC       Ending location in storage
000C   12 Signed       4 XLOCCNT        Location counter
0010   16 Character   16 RSVD0          Reserved
0020   32 Bitstring    4 XLDRFLGS       Module flag
0020   32 Bitstring    1 XLDRNOER
          .... .1..      NOERASE        X'04'
          .... ...1      SYSTEM         X'01'
0021   33 Bitstring    1 XLDRSTRN
          1... ....      STRINIT        X'80'
0022   34 Bitstring    2 RESERVED
0024   36 Character    4 RSVD1          Reserved and must be zero
0028   40 Bitstring    2 TABLENT        # Loader Table Entries
002A   42 Character    1 RSVD2          Reserved and must be zero
002B   43 Bitstring    1 MODFLAG        Module flag
          1... ....      NOLOADMF       X'80' Indicates 'No Load Map'
          .1.. ....      CLEAROPT       X'40' CLEAR option flag
          ..1. ....      MODDOS         X'20' Generated with DOS option
          ...1 ....      MODALL         X'10' Generated with ALL option
          .... ..1.      MAP24BYT       X'02' Map entries are 24 bytes
          .... ...1      POSTXA         X'01' Module gen'd by CMS 5.5 or
                                        later
002C   44 Bitstring    1 MODEFLAG       AMODE/RMODE flag
          1... ....      AMODE31        X'80' Indicates an AMODE of 31
          .1.. ....      AMODE24        X'40' Indicates an AMODE of 24
          11.. ....      AMODEANY       X'C0' Indicates an AMODE of ANY
          ..1. ....      RMODEANY       X'20' Indicates an RMODE of ANY
          ...1 ....      RMODE24        X'10' Indicates an RMODE of 24
002D   45 Bitstring    1 RLDFLAG        Relocation flag
          1... ....      RELODATA       X'80' RLD data does exist
          .1.. ....      FORMAT31       X'40' 31 bit RLD entries
          ..1. ....      TWORLD         X'20' 2 RLD recs in file
          ...1 ....      CLEANMOD       X'10' Cleanup module at end of
                                        svc
          .... 1...      FIXDTRNS       X'08' Fixed transient area module
002E   46 Bitstring    1 ARCFLAG        Architecture flag
          1... ....      INVLD370       X'80' 370 architecture is invalid
          .1.. ....      INVALXA        X'40' XA architecture is invalid
          ..1. ....      INVALXC        X'20' XC architecture is invalid
002F   47 Bitstring    1 *              Reserved
0030   48 Bitstring    2 RLDRECS        Number of RLD records in the
                                        module
0032   50 Bitstring    2 LRLDBYTS       Number of bytes in last rld
                                        record - bfs files only
0034   52 Signed       4 HISTSIZE       Size of the history data in bytes
                                        - bfs files only
0038   56 Bitstring    2 ICATCH         Module eye catcher for DMSEXC
0040   64 Dbl-Word     8 * (0)
          00000040       MODHDLEN       *-MODHDCB MODHDCB length in bytes
          00000008       MODDBLEN       (MODHDLEN+7)/8 MODHDCB length in
                                        dw

MODHDCB Storage Layout

*** MODHDCB - Module Header Control Block
*
*     +-------------------------------------------------------+
*   0 |                                                       |
*     =                       NUCONMAP                        =
*     |                                                       |
*     +-------------------------------------------------------+
*  28
*
*** MODHDCB - Module Header Control Block
*** Overlay for NUCONMAP in MODHDCB
*
*     +---------------------------+---------------------------+
*   0 |         STARTADR          |         XFRSTLOC          |
*     +---------------------------+---------------------------+
*   8 |         XLASTLOC          |         XLOCCNT           |
*     +---------------------------+---------------------------+
*  10 |                        RSVD0                          |
*     |                                                       |
*     +---------------------------+---------------------------+
*  20 |         XLDRFLGS          | 24
*     +---------------------------+
*
*** Overlay for NUCONMAP in MODHDCB
*** Overlay for XLDRFLGS in MODHDCB
*
*     +------+------+-------------+---------------------------+
*  20 |:RNOER|:RSTRN|/////////////|          RSVD1            |
*     +------+------+------+------+------+------+------+------+
*  28 |  TABLENT    |RSVD2 |:FLAG |:EFLAG|:FLAG |:FLAG |//////|
*     +-------------+------+------+------+------+------+------+
*  30 |  RLDRECS    |  LRLDBYTS   |         HISTSIZE          |
*     +-------------+-------------+---------------------------+
*  38 |   ICATCH    |/////////////////////////////////////////|
*     +-------------+-----------------------------------------+
*  40
*
*** Overlay for XLDRFLGS in MODHDCB