NDMBK

Prolog  

Control Block Contents  
   NDMBK DSECT

Storage Layout  

Cross Reference (Contains links to field and bit definitions)  

NDMBK Prolog

 NAME       : HCPNDMBK
 DESCRIPTION: Network Device Message Block
 DSECT      : NDMBK
 FUNCTION   :
              Define a structure to represent a Network Device Message.
              One NDMBK exists for to represent each message frame
              created for a Network Interface Device (NID).
 LOCATED BY -
   NIDNDMHD = Pointer to the first NDMBK for the device.
   NIDNDMTL = Pointer to the last NDMBK for the device.
 CREATED BY :
              Receipt of a message for a Network Interface Device.
 DELETED BY :
              Delivery of a message for a Network Interface Device.

NDMBK Control Block Content

NDMBK DSECT

Hex   Dec Type/Val   Lng Label (dup)    Comments
---- ---- --------- ---- -------------- --------
0000    0 Structure      NDMBK          Network Device Message Block
     Chain pointers (maintained by the NDMBK user).
0000    0 Address      4 NDMFPNT        Pointer to Next NDMBK
0004    4 Address      4 NDMBPNT        Pointer to Previous NDMBK
     Static attributes (maintained by the support routines).
0008    8 Bitstring    1 NDMATTR        Message Attributes
          1... ....      NDMALLOC       X'80' - Storage was allocated
          .1.. ....      NDMFRAME       X'40' - Allocated a 4K frame
          ..1. ....      NDMPRIME       X'20' - This is a PRIMARY NDMBK
          ...1 ....      NDMCLONE       X'10' - This is a CLONE NDMBK
0009    9 Bitstring    1 NDMFLAGS       Message Flags
          1... ....      NDMDVHDR       X'80' - NDMBK includes Device
                                        Header
          .1.. ....      NDMXDATA       X'40' - NDMBK includes XFER Data
000A   10 Bitstring    1 NDMDTYPE       Data type
          00000000       NDMUCDAT       0 - Unicast (nonrouter) data
          00000004       NDMRTDAT       4 - Unicast (router) data
          00000008       NDMMCDAT       8 - Multicast data
          0000000C       NDMBCDAT       12 - Broadcast data
000B   11 Bitstring    1 NDMFLAG3       Additional Flags (local usage)
000C   12 Address      4 NDMCHAIN       Pointer to NDMBK fragment chain
     Message-specific area (NDMSPEC).
0010   16 Signed       4 NDMSPEC (0)
     Normal message attributes.
     ******* ORG NDMSPEC Overlay for a Normal message
0010   16 Address      4 NDMBUFAD       Pointer to Original Buffer
0014   20 Signed       4 NDMRFCTR       Reference counter
0018   24 Bitstring    8 NDMPARMS (0)   Message parms
                                        <length,address>
0018   24 Signed       4 NDMBYTES       Length of message in bytes
001C   28 Address      4 NDMDATA        Pointer to message data
     Cloned message (referencing a Primary message).
0010   16 Address      4 NDMORIG        Pointer to Primary NDMBK
0014   20 Bitstring    4 *              Reserved
0018   24 Signed       4 *              (NDMBYTES) Length of message in
                                        bytes
001C   28 Address      4 *              (NDMDATA) Pointer to message data
     End of NDMBK structure.
0020   32 Bitstring    1 NDM$END (0)    End of NDMBK
          00000020       NDMBKLN        *-NDMBK Length of NICBK in bytes
          00000004       NDMBKSZ        (*-NDMBK+7)/8 Size of NICBK in
                                        doublewords

NDMBK Storage Layout

          
*** NDMBK - Network Device Message Block
*
*     +---------------------------+---------------------------+
*   0 |         NDMFPNT           |         NDMBPNT           |
*     +------+------+------+------+---------------------------+
*   8 |:ATTR |:FLAGS|:DTYPE|:FLAG3|         NDMCHAIN          |
*     +------+------+------+------+---------------------------+
*  10 |         NDMBUFAD          |         NDMRFCTR          |
*     +---------------------------+---------------------------+
*  18 |         NDMBYTES          |         NDMDATA           |
*     +---------------------------+---------------------------+
*  20
*
*** NDMBK - Network Device Message Block
          
*** Overlay for NDMSPEC in NDMBK
*
*     +---------------------------+---------------------------+
*  10 |         NDMORIG           |///////////////////////////|
*     +---------------------------+---------------------------+
*  18 |///////////////////////////|///////////////////////////|
*     +---------------------------+---------------------------+
*
*** Overlay for NDMSPEC in NDMBK

NDMBK Cross Reference

Symbol         Dspl Value
-------------- ---- -----
NDM$END        0020
NDMALLOC       0008 80
NDMATTR        0008
NDMBCDAT       000A 0000000C
NDMBKLN        0020 00000020
NDMBKSZ        0020 00000004
NDMBPNT        0004
NDMBUFAD       0010
NDMBYTES       0018
NDMCHAIN       000C
NDMCLONE       0008 10
NDMDATA        001C
NDMDTYPE       000A
NDMDVHDR       0009 80
NDMFLAGS       0009
NDMFLAG3       000B
NDMFPNT        0000
NDMFRAME       0008 40
NDMMCDAT       000A 00000008
NDMORIG        0010
NDMPARMS       0018
NDMPRIME       0008 20
NDMRFCTR       0014
NDMRTDAT       000A 00000004
NDMSPEC        0010
NDMUCDAT       000A 00000000
NDMXDATA       0009 40