NAME       : PGAUX
 DESCRIPTION: Page Auxiliary Status Table Entry
 DSECT      : PGAUX
 FUNCTION   : Auxiliary extension of the PGSTE
              PGAUX is a multi-purpose area:
              - When PGSTE.PGSOVFLW=1, then PGAUX contains
              an overflow pin count.
              - When a page is IBR (PGSTE.PGSIBR=1 or
              PGSTE.PGSAGING=1), then PGAUX contains
              a portion of a timestamp used to record
              IBR state changes.
              It is the developer's responsibility to ensure
              residual data is cleared from PGAUX before
              repurposing the field.
 LOCATED BY : PGMGPAUX  Field of HCPPGMBK + PTE offset / 2
              A page auxiliary status table resides in a
              page management block associated with a megabyte
              of virtual storage and is addressed by label
              PGMGPAUX.  There are 256 contiguous page auxiliary
              status table entries (PGAUXs) contained in the
              PGMBK.
              Any specific aux table entry can be obtained by
              extracting the page index from a virtual address,
              multiplying it by the length of an aux entry, and
              adding this offset to the start of the page status
              table.  Also, using the address of a PAGTE as the
              address of a VPGBK, the corresponding PGAUX can be
              found by calculating the offset of the PTE from the
              page table origin, dividing by two, and adding the
              resulting word offset to the start of the page
              auxiliary status table.
              Utility macro HCPPTEAX can be used to fetch and
              modify the PGAUX area for a specific PTE.
 CREATED BY : A page status aux table is imbedded in a page
              management block.  Consequently, space is created
              for it when the PGMBK is created.
 DELETED BY : HCPHPKPA
              A page status aux table is deleted when a page
              management block is released.
 SERIALIZED :
              Serialized by PTE/PGSTE serialization, either
              Shortterm or PCLONLY.
 RELOCATION CONSIDERATIONS : None

 PGAUX DSECT
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Hex   Dec Type/Val   Lng Label (dup)    Comments
---- ---- --------- ---- -------------- --------
0000    0 Structure      PGAUX          Page Auxiliary Status Table Entry
0000    0 Signed       4 PGAUXENT (0)   Aux entry
0000    0 Signed       2 *              Reserved for IBM use
0002    2 Signed       2 PGAOVFLW       Overflow pin count Count of the
                                        number of 128 pin- count overflow
                                        increments. Each increment of
                                        ASAOVFLW represents 128 pins. The
                                        pin count for a page is kept in
                                        PGSPINCT, which is only 1 byte in
                                        length and can hold up to 127 pin
                                        increments. If that overflows,
                                        ASAOVFLW is incremented and
                                        therefore represents 128 pins.
                                        Note that ASAOVFLW can be changed
                                        with PCLONLY page serialization
                                        by those tasks that are allowed
                                        to use PCLONLY.

          
*** PGAUX - Page Auxiliary Status Table Entry
*
*     +-------------+-------------+
*   0 |/////////////|  PGAOVFLW   | 4
*     +-------------+-------------+
*
*** PGAUX - Page Auxiliary Status Table Entry

 
Symbol         Dspl Value
-------------- ---- -----
PGAOVFLW       0002
PGAUXENT       0000