Programming Interface Information: This information is NOT intended to be
used as Programming Interfaces of VM/ESA. It is to be used for diagnosis only.

PGEBK

Prolog  

Control Block Contents  

PGEBK DSECT

Storage Layout  

Cross Reference (Contains links to field and bit definitions)  

PGEBK Prolog

 NAME       : HCPPGEBK
 DESCRIPTION: Page Allocation Management Block
 DSECT      : PGEBK
 FUNCTION   : Maintain a record of virtual pages that have
              been allocated within the virtual address space
              used for the ISFC subsystem and within virtual address
              spaces of applications using ISFC.
              Also used as a communications buffer descriptor for SNA
              support.  The buffer itself may reside in
              CP real storage (in which case, PGEALET will be zero) or
              in a "permanently" accessed address space (in which case
              PGEALET will be the ALET of the address space).
 NOTES      : For SNA Support,
              the data within a buffer need not start in the first byte
              of the buffer, and it need not extend to the end of the
              buffer.  Hence, we need the PGEDATOF and PGEDATLN fields.
              Even if the data does not fill up the entire buffer, it is
              assumed that all of the storage of the buffer is available
              for use.  E.g., if the data starts at some non-zero offset
              into the buffer, then SNA headers may be inserted into the
              buffer ahead of the data (assuming that they fit).
              The prototypical PL/X basing expression is:
      respecify
        buffer  based(viaptr(pgeALET, pgeVirt+pgeDatOf))
              Of course, the buffer can only be accessed in AR-mode.
              Each buffer has a unique creator, and a current owner.
              Only the current owner of a buffer may reference and/or
              modify the buffer and/or the fields in the buffer
              descriptor -- only the buffer's creator may deallocate the
              storage occupied by the buffer and/or the PGEBK.  When a
              buffer has been consumed, it should be returned to its
              creator by calling the creator's RECLAIM-BUF exit, which
              is pointed to by the PGECLAIM field.
              The fields in this control block are initialized by the
              buffer's creator -- all of them are read-only to everyone
              else *except* for PGENEXT, PGEDATOF, PGEDATLN, and the
              owner pointers and words.
 LOCATED BY : When a virtual page is in use, the PGEBK address
              is stored in an appropriate control block.  For
              example: The CTCBK contains a table with one
              PGEBK pointer for each buffer that has been set
              up for the Read channel program.
 CREATED BY : For ISFC, created by HCPBUT when a new virtual page buffer
              is requested.  PGEBKs that HCPBUT creates always have
              host virtual addresses from the ISFC Address Space ass-
              ociated with them.  PGEBKs are also obtained by other
              communication transports without using HCPBUT and by
              applications that use ISFC services.
 DELETED BY : For ISFC, deleted by HCPBUT when the virtual page buffer
              is released.  PGEBKs obtained by other communications
              transports without using HCPBUT must not be returned using
              HCPBUT.  These must be returned using a method appropriate
              with respect to how they were obtained by the transport.
              See description of PGECLAIM above.
 SERIALIZED : The ISFC global lock (HCPBDSGL).

 

PGEBK Control Block Content


PGEBK DSECT

Hex Dec Type/Val Lng Label (dup) Comments ---- ---- --------- ---- -------------- -------- 0000 0 Structure PGEBK Page Allocation Management Block 0000 0 Bitstring 8 PGEEYE Unused eye catcher 0008 8 Address 4 PGENEXT Address of next PGEBK 000C 12 Signed 4 PGEINST ISFC instance for this virt. page 0010 16 Address 4 PGELNKBK LNKBK address received over 0014 20 Address 4 PGEVMDBK VMDBK of address space address 0018 24 Address 4 PGECLAIM Address of entry point 001C 28 Signed 4 PGEREAL Real address of locked page 0020 32 Signed 4 PGEBFLEN Length of buffer 0024 36 Signed 4 PGEDATOF Offset of data into buffer 0028 40 Signed 4 PGEDATLN Length of data in buffer 002C 44 Signed 4 PGEALET ALET that can be used to refer to the system virtual address in PGEVIRT with CP in DAT-on, host Access Register mode. 0030 48 Signed 4 PGEVIRT Virtual page address relative to the ALET 0034 52 Address 4 PGECRPTR Pointer for creators use 0038 56 Signed 4 PGECRWRD Word for creators use 003C 60 Signed 4 PGECRW2 Word 2 for creators use 0040 64 Address 4 PGEOWPTR Pointer for owners use 0044 68 Signed 4 PGEOWWRD Word for owners use 0048 72 Signed 4 PGEOWW2 Word 2 for owners use 004C 76 Signed 4 * Reserved 0050 80 Dbl-Word 8 PGEIASIT I-ASIT for page 0000000B PGESIZE (*-PGEBK+7)/8 Size, in doublewords, of PGEBK

 

PGEBK Storage Layout

*** PGEBK - Page Allocation Management Block
*
*     +-------------------------------------------------------+
*   0 |                        PGEEYE                         |
*     +---------------------------+---------------------------+
*   8 |         PGENEXT           |         PGEINST           |
*     +---------------------------+---------------------------+
*  10 |         PGELNKBK          |         PGEVMDBK          |
*     +---------------------------+---------------------------+
*  18 |         PGECLAIM          |         PGEREAL           |
*     +---------------------------+---------------------------+
*  20 |         PGEBFLEN          |         PGEDATOF          |
*     +---------------------------+---------------------------+
*  28 |         PGEDATLN          |         PGEALET           |
*     +---------------------------+---------------------------+
*  30 |         PGEVIRT           |         PGECRPTR          |
*     +---------------------------+---------------------------+
*  38 |         PGECRWRD          |         PGECRW2           |
*     +---------------------------+---------------------------+
*  40 |         PGEOWPTR          |         PGEOWWRD          |
*     +---------------------------+---------------------------+
*  48 |         PGEOWW2           |///////////////////////////|
*     +---------------------------+---------------------------+
*  50 |                       PGEIASIT                        |
*     +-------------------------------------------------------+
*  58
*
*** PGEBK - Page Allocation Management Block

 

PGEBK Cross Reference

(contains links to field and bit definitions)
Symbol         Dspl Value
-------------- ---- -----

PGEALET 002C

PGEBFLEN 0020

PGECLAIM 0018

PGECRPTR 0034

PGECRWRD 0038

PGECRW2 003C

PGEDATLN 0028

PGEDATOF 0024

PGEEYE 0000

PGEIASIT 0050

PGEINST 000C

PGELNKBK 0010

PGENEXT 0008

PGEOWPTR 0040

PGEOWWRD 0044

PGEOWW2 0048

PGEREAL 001C

PGESIZE 0050 0000000B

PGEVIRT 0030

PGEVMDBK 0014


This information is based on VM/ESA 2.4.0.
Last updated on 3 Aug 1999 at 12:22:42 EDT.
Copyright IBM Corporation, 1990, 1999