Programming Interface Information: This information is NOT intended to be used as Programming Interfaces of z/VM.

#### 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
    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 POFLAG         X'80' nucon uses as UNRES flag
              .1.. ....      ISAPO          X'40' Module is a program object
    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
    003A   58 Bitstring    2 POREC          First PO record number
    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 - Control Block in MODHDCB
    *
    *     +-------------------------------------------------------+
    *   0 |                                                       |
    *     =                       NUCONMAP                        =
    *     |                                                       |
    *     +-------------------------------------------------------+
    *  28
    *
    *** MODHDCB - Control Block in MODHDCB

    *** 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    |POFLAG|:FLAG |:EFLAG|:FLAG |:FLAG |//////|
    *     +-------------+------+------+------+------+------+------+
    *  30 |  RLDRECS    |  LRLDBYTS   |         HISTSIZE          |
    *     +-------------+-------------+---------------------------+
    *  38 |   ICATCH    |   POREC     |///////////////////////////|
    *     +-------------+-------------+---------------------------+
    *  40
    *
    *** Overlay for XLDRFLGS in MODHDCB

#### MODHDCB Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    AMODEANY       002C C0
    AMODE24        002C 40
    AMODE31        002C 80
    ARCFLAG        002E
    CLEANMOD       002D 10
    CLEAROPT       002B 40
    FIXDTRNS       002D 08
    FORMAT31       002D 40
    HISTSIZE       0034
    ICATCH         0038
    INVALXA        002E 40
    INVALXC        002E 20
    INVLD370       002E 80
    ISAPO          002A 40
    LRLDBYTS       0032
    MAP24BYT       002B 02
    MODALL         002B 10
    MODDBLEN       0040 00000008
    MODDOS         002B 20
    MODEFLAG       002C
    MODFLAG        002B
    MODHDLEN       0040 00000040
    NOERASE        0020 04
    NOLOADMF       002B 80
    NUCONMAP       0000
    POFLAG         002A
    POREC          003A
    POSTXA         002B 01
    RELODATA       002D 80
    RESERVED       0022
    RLDFLAG        002D
    RLDRECS        0030
    RMODEANY       002C 20
    RMODE24        002C 10
    RSVD0          0010
    RSVD1          0024
    STARTADR       0000
    STRINIT        0021 80
    SYSTEM         0020 01
    TABLENT        0028
    TWORLD         002D 20
    XFRSTLOC       0004
    XLASTLOC       0008
    XLDRFLGS       0020
    XLDRNOER       0020
    XLDRSTRN       0021
    XLOCCNT        000C

This information is based on z/VM V4R4.0.
Last updated on 28 Jul 2003 at 08:16:16 EDT.
Copyright IBM Corporation, 1990, 2003