Programming Interface Information:
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NDMBK
Control Block Contents
NDMBK DSECT
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. .... NDMSHARE X'20' - This is a shared data area ...1 .... NDMCLONE X'10' - This is a CLONE 0009 9 Bitstring 3 * Reserved 000C 12 Signed 4 NDMSPEC (0) Normal message attributes. ******* ORG NDMSPEC Overlay for a Normal message 000C 12 Address 4 NDMBUFAD Pointer to Original Buffer 0010 16 Signed 4 NDMBYTES Length of message in bytes 0014 20 Address 4 NDMDATA Pointer to message data Primary message (referenced by a clone). 000C 12 Address 4 * (NDMBUFAD) Pointer to Original Buffer 0010 16 Signed 4 NDMRFCTR Reference Counter 0014 20 Bitstring 4 * Reserved Cloned message (referencing a Primary message). 000C 12 Address 4 NDMORIG Pointer to Primary NDMBK 0010 16 Signed 4 * (NDMBYTES) Length of message in bytes 0014 20 Address 4 * (NDMDATA) Pointer to message data End of NDMBK structure. 0018 24 Bitstring 1 NDM$END (0) End of NDMBK 00000018 NDMBKLN *-NDMBK Length of NICBK in bytes 00000003 NDMBKSZ (*-NDMBK+7)/8 Size of NICBK in doublewords
NDMBK Storage Layout
*** NDMBK - Network Device Message Block * * +---------------------------+---------------------------+ * 0 | NDMFPNT | NDMBPNT | * +------+--------------------+---------------------------+ * 8 |:ATTR |////////////////////| NDMBUFAD | * +------+--------------------+---------------------------+ * 10 | NDMBYTES | NDMDATA | * +---------------------------+---------------------------+ * 18 * *** NDMBK - Network Device Message Block *** Overlay for NDMSPEC in NDMBK * * +---------------------------+ * 8 ... C |///////////////////////////| * +---------------------------+---------------------------+ * 10 | NDMRFCTR |///////////////////////////| * +---------------------------+---------------------------+ * 18 * *** Overlay for NDMSPEC in NDMBK *** Overlay for NDMSPEC in NDMBK * * +---------------------------+ * 8 ... C | NDMORIG | * +---------------------------+---------------------------+ * 10 |///////////////////////////|///////////////////////////| * +---------------------------+---------------------------+ * *** Overlay for NDMSPEC in NDMBK
NDMBK Cross Reference
Symbol Dspl Value -------------- ---- ----- NDM$END 0018 NDMALLOC 0008 80 NDMATTR 0008 NDMBKLN 0018 00000018 NDMBKSZ 0018 00000003 NDMBPNT 0004 NDMBUFAD 000C NDMBYTES 0010 NDMCLONE 0008 10 NDMDATA 0014 NDMFPNT 0000 NDMFRAME 0008 40 NDMORIG 000C NDMRFCTR 0010 NDMSHARE 0008 20 NDMSPEC 000C
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