NAME       : HCPFSCBK
 DESCRIPTION: Free Storage Counter Block
 DSECT      : FSCBK
 FUNCTION   : Storage accounting for control blocks used in
              the free storage limit detection function.
 LOCATED BY : VMDFSCBK field of HCPVMDBK
 CREATED BY : HCPBVM for an origin VMDBK. Non-origin VMDBKs
              are assigned the address of the origin FSCBK.
 DELETED BY : HCPUSP deletes the FSCBK when the origin VMDBK
              logs off if FSCCOUNT is zero, Otherwise it will
              be released when HCPFRGDC decrements FSCCOUNT
              to zero.
 SERIALIZED : Informal spin lock FSCLOCK will be used to
              serialize the FSCCOUNT, FSCGRACE and FSCFLAG
              fields.

 FSCBK DSECT
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Hex   Dec Type/Val   Lng Label (dup)    Comments
---- ---- --------- ---- -------------- --------
0000    0 Structure      FSCBK          Free Storage Counter Block
0000    0 Dbl-Word     8 FSCUSER (0)    Userid if user has logged off.
0000    0 Signed       4 FSCVMDBK       Origin VMDBK address if user is
                                        logged on.
0004    4 Signed       4 *              Reserved for IBM use.
0008    8 Dbl-Word     8 FSCGRACE       Timestamp for grace period.
                                        FSCLOCK must be held to update
                                        this field.
0010   16 Signed       4 FSCCOUNT       Number of doublewords of free
                                        storage currently held by user
                                        for monitored control blocks.
                                        FSCLOCK must be held to update
                                        this field.
0014   20 Signed       4 FSCSTATS (0)   Limit detection status
0014   20 Bitstring    1 * (3)          Reserved for IBM use.
0017   23 Bitstring    1 FSCFLAG        Flags. Serialized with FSCLOCK.
          .1.. ....      FSCWRNG        X'40' FSCWRNG Warning message was
                                        issued.
          ..1. ....      FSCSTOP        X'20' FSCSTOP Virtual machine is
                                        placed in a stopped sta 2nd
                                        message was issued.
          ...1 ....      FSCFORCE       X'10' FSCFORCE Logoff message was
                                        issued.
          .... 1...      FSCEXMPT       X'08' FSCEXMPT User is exempt
                                        from the stop and force ac of the
                                        free storage limit detection
                                        function.
          .... .1..      FSCGRCON       X'04' FSCGRCON A 1 minute grace
                                        period is allowed
0018   24 Signed       4 FSCLOCK        This is an informal spin lock.
                                        The lock must be held to update
                                        COUNT, GRACE and FLAGS. Use test
                                        and set to update.
          00000004       FSCSIZE        ((*-FSCBK)+7)/8 FSCBK size in
                                        double-words

          
*** FSCBK - Free Storage Counter Block
*
*     +---------------------------+---------------------------+
*   0 |         FSCVMDBK          |///////////////////////////|
*     +---------------------------+---------------------------+
*   8 |                       FSCGRACE                        |
*     +---------------------------+--------------------+------+
*  10 |         FSCCOUNT          |////////////////////|:FLAG |
*     +---------------------------+--------------------+------+
*  18 |         FSCLOCK           | 1C
*     +---------------------------+
*
*** FSCBK - Free Storage Counter Block

 
Symbol         Dspl Value
-------------- ---- -----
FSCCOUNT       0010
FSCEXMPT       0017 08
FSCFLAG        0017
FSCFORCE       0017 10
FSCGRACE       0008
FSCGRCON       0017 04
FSCLOCK        0018
FSCSIZE        0018 00000004
FSCSTATS       0014
FSCSTOP        0017 20
FSCUSER        0000
FSCVMDBK       0000
FSCWRNG        0017 40