MDGBK

Prolog  

Control Block Contents  
   MDGBK DSECT

Storage Layout  

Cross Reference (Contains links to field and bit definitions)  

MDGBK Prolog

 NAME       : HCPMDGBK
 DESCRIPTION: MONDIAG control block
 DSECT      : MDGBK
 FUNCTION   : Information relating to an application buffer
              created by the virtual machine via Diagnose 'DC'.
 LOCATED BY : MNDA_MDGBK_LHEAD:  Beginning of MONDIAG chain
              MNDA_MDGBK_LTAIL:  End of MONDIAG chain
 CREATED BY : HCPMXPDC        Diagnose 'DC' START processing
              HCPMXSEV        Diagnose 'DC' EVENT processing
              HCPMXTCF        Diagnose 'DC' CONFIG processing
 DELETED BY : HCPMXSSP        Diagnose 'DC' STOP  processing
              HCPMXSEV        Diagnose 'DC' EVENT processing
 REFERENCES : none
 SERIALIZED : The chain of HCPMDGBKs is serialized by the defer
              lock MNDA_MDGBK_LOCK, which is located in HCPMNDBK.
 NOTES      : -- An MDGBK is created for each invocation of Diagnose 'DC' START
              -- An MDGBK is deleted under the following circumstances:
              - When a Diagnose 'DC' STOP is issued
              - When a virtual storage reset is detected
              - When a segment purge occurs and it is determined
              that an application buffer resides within the
              address range of the NSS that is to be purged

MDGBK Control Block Content

MDGBK DSECT

Hex   Dec Type/Val   Lng Label (dup)    Comments
---- ---- --------- ---- -------------- --------
0000    0 Structure      MDGBK          MONDIAG control block
0000    0 Address      4 MDG_NEXT       Pointer to next MDGBK block in
                                        chain
0004    4 Address      4 MDG_PREV       Pointer to previous MDGBK block
                                        in chain
0008    8 Address      4 MDG_APBUF_GAA1 Guest absolute address of the
                                        first page of the application
                                        buffer associated with this MDGBK
000C   12 Address      4 MDG_APBUF_GAA2 Guest absolute address of the
                                        second page of the application
                                        buffer associated with this
                                        MDGBK. Applicable only when the
                                        application buffer crosses a page
                                        boundary, otherwise set to FFs.
0010   16 Character   16 MDG_PROD_ID    Product-id and release id of the
                                        application placing the data in
                                        the buffer
0020   32 Address      4 MDG_VMDKB_ADDR Address of the Base VMDBK that
                                        owns this application buffer
0024   36 Address      2 MDG_BUFF_LEN   Total length (in bytes) of the
                                        application buffer. It will
                                        always be the sum of
                                        MDG_BUFF_LEN1 and MDG_BUFF_LEN2
0026   38 Address      2 MDG_BUFF_LEN1  Length (in bytes) of the first
                                        page of the application buffer
0028   40 Address      2 MDG_BUFF_LEN2  Length (in bytes) of the second
                                        page of the application buffer.
                                        Set to 0 unless the buffer
                                        crosses a page boundary.
002A   42 Bitstring    1 MDG_STATUS     Status flags
002B   43 Bitstring    1 *              Reserved for IBM use
002C   44 Address      4 MDG_SNTBK_ADDR1
                                        Address of the 1st SNTBK if the
                                        application buffer address is
                                        within a saved segment
0030   48 Address      4 MDG_SNTBK_ADDR2
                                        Address of the 2nd SNTBK if the
                                        application buffer address is
                                        within two saved segements
0034   52 Bitstring    4 *              Reserved for IBM use
          00000038       MDG$END        *

MDGBK Storage Layout

          
*** MDGBK - MONDIAG control block
*
*     +---------------------------+---------------------------+
*   0 |         MDG_NEXT          |         MDG_PREV          |
*     +---------------------------+---------------------------+
*   8 |      MDG_APBUF_GAA1       |      MDG_APBUF_GAA2       |
*     +---------------------------+---------------------------+
*  10 |                     MDG_PROD_ID                       |
*     |                                                       |
*     +---------------------------+-------------+-------------+
*  20 |      MDG_VMDKB_ADDR       |MDG_BUFF_LEN |MDG_BUFF_LEN1|
*     +-------------+------+------+-------------+-------------+
*  28 |MDG_BUFF_LEN2|(02A) |//////|     MDG_SNTBK_ADDR1       |
*     +-------------+------+------+---------------------------+
*  30 |     MDG_SNTBK_ADDR2       |///////////////////////////|
*     +---------------------------+---------------------------+
*  38
*
*** MDGBK - MONDIAG control block

MDGBK Cross Reference

Symbol         Dspl Value
-------------- ---- -----
MDG$END        0034 00000038
MDG_APBUF_GAA1
               0008
MDG_APBUF_GAA2
               000C
MDG_BUFF_LEN   0024
MDG_BUFF_LEN1  0026
MDG_BUFF_LEN2  0028
MDG_NEXT       0000
MDG_PREV       0004
MDG_PROD_ID    0010
MDG_SNTBK_ADDR1
               002C
MDG_SNTBK_ADDR2
               0030
MDG_STATUS     002A
MDG_VMDKB_ADDR
               0020