NAME       : HCPCAABK
 DESCRIPTION: CP-use Address space Allocation block
 DSECT      : CAABK
 FUNCTION   : Allocation of virtual addresses in CP-use
              address spaces
 LOCATED BY : ASCTYPTR field of ASCBK
 CREATED BY : Creation of a HCPHAM-managed address space, either
              by HCPASMCR or its callers.
 DELETED BY : Never deleted.
 SERIALIZED :
              All fields except reorganization fields serialized
              by CAALOCK held exclusive.  ASCLOCK in the ASCBK for
              this address space must be held shared when obtain-
              CAALOCK.  If ASCLOCK is held exclusive, CAALOCK need
              not be held.
 RELOCATION CONSIDERATIONS : None

 CAABK DSECT
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Hex   Dec Type/Val   Lng Label (dup)    Comments
---- ---- --------- ---- -------------- --------
0000    0 Structure      CAABK          CP-use Address space Allocation block
0000    0 Address      8 CAAAVAIL       Anchor of a chain of PGMBK
                                        FRMTE(s) containing all
                                        deallocated PTEs below the
                                        address space's high water mark
                                        (CAAHIWTR). The PGMBK FRMTE(s) on
                                        this chain are sorted in
                                        ascending virtual address order.
                                        A CAAAVAIL of zeros indicates an
                                        empty chain. This chain is ended
                                        by a fullword of zeros in
                                        FRMFPNTG. Hold CAALOCK or ASCLOCK
                                        exclusive when updating this
                                        field.
0008    8 Dbl-Word     8 CAAHIWTR       Virtual page address
                                        corresponding to the next
                                        available PTE in this CP-use
                                        address space. All pages below
                                        this mark are either currently
                                        allocated or are chained on
                                        CAAAVAIL. CAAHIWTR never points
                                        at an allocated page. No pages
                                        above CAAHIWTR are ever allocated
                                        or chained on CAAAVAIL. Hold
                                        CAALOCK or ASCLOCK exclusive when
                                        updating this field.
0008    8 Signed       4 CAAHIWTRH      High half of virtual address
000C   12 Signed       4 CAAHIWTRL      Low half of virtual address
0010   16 Signed       4 CAAFPTE        Count of PTEs in this CP-use
                                        address space that exist but do
                                        not currently hold an allocated
                                        page. This number is an
                                        indication of the amount of host
                                        real storage currently allocated
                                        to map this CP-use address space,
                                        but is not being used. This
                                        number can therefore be used to
                                        determine when it would be
                                        beneficial to reorganize the
                                        address space. Hold CAALOCK or
                                        ASCLOCK exclusive when updating
                                        this field.
0014   20 Signed       4 CAAUSTE        Count of used segment table
                                        entries in this CP-use address
                                        space. Hold CAALOCK or or ASCLOCK
                                        exclusive when updating this
                                        field.
0018   24 Signed       4 CAALOCK        CP-use address space allocation
                                        lock. This is an informal spin
                                        lock. Must be held when updating
                                        certain CAABK fields (see above).
                                        ASCLOCK must be held shared to
                                        obtain this lock. If ASCLOCK is
                                        held exclusive, there is no need
                                        to obtain this lock.
001C   28 Signed       4 CAAROGCT       Number of times this address
                                        space has been reorganized. Hold
                                        CAAROGLK when updating this
                                        field.
0020   32 Dbl-Word     8 CAAREORG       Time of day last reorganization
                                        occured for this address space.
                                        Hold CAAROGLK when updating this
                                        field.
0028   40 Bitstring    1 CAAROGLK       Address space reorganization test
                                        and set (TS) lock.
0029   41 Bitstring    1 * (3)          Reserved for future IBM use
002C   44 Signed       4 * (3)          Reserved for future IBM use
0038   56 Signed       4 CAAFSI (0)     Function-specific information
                                        section
          00000007       CAASIZE        (*-CAABK+7)/8 Size, in
                                        doublewords, of CAABK.

          
*** CAABK - CP-use Address space Allocation block
*
*     +-------------------------------------------------------+
*   0 |                       CAAAVAIL                        |
*     +-------------------------------------------------------+
*   8 |                       CAAHIWTR                        |
*     +-------------------------------------------------------+
*  10
*
*** CAABK - CP-use Address space Allocation block
          
*** Overlay for CAAHIWTR in CAABK
*
*     +---------------------------+---------------------------+
*   8 |        CAAHIWTRH          |        CAAHIWTRL          |
*     +---------------------------+---------------------------+
*  10 |         CAAFPTE           |         CAAUSTE           |
*     +---------------------------+---------------------------+
*  18 |         CAALOCK           |         CAAROGCT          |
*     +---------------------------+---------------------------+
*  20 |                       CAAREORG                        |
*     +------+--------------------+---------------------------+
*  28 |:ROGLK|////////////////////|///////////////////////////|
*     +------+--------------------+///////////////////////////|
*     |///////////////////////////////////////////////////////|
*     +-------------------------------------------------------+
*
*** Overlay for CAAHIWTR in CAABK

 
Symbol         Dspl Value
-------------- ---- -----
CAAAVAIL       0000
CAAFPTE        0010
CAAFSI         0038
CAAHIWTR       0008
CAAHIWTRH      0008
CAAHIWTRL      000C
CAALOCK        0018
CAAREORG       0020
CAAROGCT       001C
CAAROGLK       0028
CAASIZE        0038 00000007
CAAUSTE        0014