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.
 RELOCATION CONSIDERATIONS : This control block is relocated as part of a live
              guest relocation (LGR).  The bits and fields that
              need to be relocated are defined in the
              corresponding LGRMDGBK COPY file.  Whenever changes
              are made to this control block, consideration must
              be given to any effects these changes will have on
              a relocation.  If any new fields or bits are
              defined, they may need to be relocated.  If
              existing bits or fields are changed, corresponding
              modifications may be required in the LGR version of
              this control block.  Consider also the effects of
              these changes on a relocation involving a back-level
              release of CP.
 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 Character    8 MDG_APBUF_GAA1_G (0)
                                        Guest absolute addr of the 1st
                                        page
0008    8 Signed       4 MDG_APBUF_GAA1_HI
                                        of the appl buffer associated
                                        with
000C   12 Signed       4 MDG_APBUF_GAA1_LO
                                        this MDGBK
0010   16 Character    8 MDG_APBUF_GAA2_G (0)
                                        Guest absolute addr of the 2nd
                                        page
0010   16 Signed       4 MDG_APBUF_GAA2_HI
                                        of the appl buffer associated
                                        with
0014   20 Signed       4 MDG_APBUF_GAA2_LO
                                        this MDGBK. Applicable only when
                                        th application buffer crosses a
                                        page boundary, otherwise set to
                                        FFs.
0018   24 Character   16 MDG_PROD_ID    Product-id and release id of the
                                        application placing the data in
                                        the buffer
0028   40 Address      4 MDG_VMDBK_ADDR Address of the Base VMDBK that
                                        owns this application buffer
002C   44 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
002E   46 Address      2 MDG_BUFF_LEN1  Length (in bytes) of the first
                                        page of the application buffer
0030   48 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.
0032   50 Bitstring    1 MDG_STATUS     Status flags
0033   51 Bitstring    1 *              Reserved for IBM use
0034   52 Address      4 MDG_SNTBK_ADDR1
                                        Address of the 1st SNTBK if the
                                        application buffer address is
                                        within a saved segment
0038   56 Address      4 MDG_SNTBK_ADDR2
                                        Address of the 2nd SNTBK if the
                                        application buffer address is
                                        within two saved segements
003C   60 Bitstring    4 *              Reserved for IBM use
          00000040       MDG$END        *
          00000008       MDGSIZE        (MDG$END-MDGBK+7)/8 MDGBK size in
                                        doublewords

MDGBK Storage Layout

          
*** MDGBK - MONDIAG control block
*
*     +---------------------------+---------------------------+
*   0 |         MDG_NEXT          |         MDG_PREV          |
*     +---------------------------+---------------------------+
*   8 |    MDG_APBUF_GAA1_HI      |    MDG_APBUF_GAA1_LO      |
*     +---------------------------+---------------------------+
*  10 |    MDG_APBUF_GAA2_HI      |    MDG_APBUF_GAA2_LO      |
*     +---------------------------+---------------------------+
*  18 |                     MDG_PROD_ID                       |
*     |                                                       |
*     +---------------------------+-------------+-------------+
*  28 |      MDG_VMDBK_ADDR       |MDG_BUFF_LEN |MDG_BUFF_LEN1|
*     +-------------+------+------+-------------+-------------+
*  30 |MDG_BUFF_LEN2|(032) |//////|     MDG_SNTBK_ADDR1       |
*     +-------------+------+------+---------------------------+
*  38 |     MDG_SNTBK_ADDR2       |///////////////////////////|
*     +---------------------------+---------------------------+
*  40
*
*** MDGBK - MONDIAG control block

MDGBK Cross Reference

Symbol         Dspl Value
-------------- ---- -----
MDG$END        003C 00000040
MDG_APBUF_GAA1_G
               0008
MDG_APBUF_GAA1_HI
               0008
MDG_APBUF_GAA1_LO
               000C
MDG_APBUF_GAA2_G
               0010
MDG_APBUF_GAA2_HI
               0010
MDG_APBUF_GAA2_LO
               0014
MDG_BUFF_LEN   002C
MDG_BUFF_LEN1  002E
MDG_BUFF_LEN2  0030
MDG_NEXT       0000
MDG_PREV       0004
MDG_PROD_ID    0018
MDG_SNTBK_ADDR1
               0034
MDG_SNTBK_ADDR2
               0038
MDG_STATUS     0032
MDG_VMDBK_ADDR
               0028
MDGSIZE        003C 00000008