NAME       : HCPEXPBK
 DESCRIPTION: EXPOSURE BLOCK
 DSECT      : EXPBK
 FUNCTION   : The exposure block contains necessary information
              about a CP volume for paging information.
 LOCATED BY : RDEVEXPB - Points to the exposure block.
 CREATED BY : HCPRDAAT - When the CP owned volume is brought on
              line at IPL time and during the ATTACH
              command processing.
 DELETED BY : HCPRDADT - When the CP owned volume is DETACHed from
              the system.
 SERIALIZED : EXPLCKCS - A typical CSGET is used to get
              serialization to serialize this control
              block and the IORBK control block for the
              exposure.
 RELOCATION CONSIDERATIONS : None
 COMMENTS   :

 EXPBK DSECT
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Hex   Dec Type/Val   Lng Label (dup)    Comments
---- ---- --------- ---- -------------- --------
0000    0 Structure      EXPBK          Paging Information Header Block
0000    0 Signed       8 EXPPHDBK (22)  Header area mapped by PHDBK
        Flags for the exposure block.
00B0  176 Signed       2 EXPCPUCS       CPUAD of obtainer of EXPLCKCS.
      These flags keep the status information for this exposure.
      This flag contains bits, but is also manipulated with a
      MVI so care must be taken to understand the relationship of
      the bits.
00B2  178 Bitstring    1 EXPSTAT1       Exposure status flag one
          .... ....      EXPIDLE        X'00' EXPIDLE Value when exposure
                                        is idle, and unsuspended, as far
                                        as paging subsystem is aware.
          1... ....      EXPINTE        X'80' EXPINTE Interrupt is
                                        expected. Turned on when: - a
                                        SSCH is stacked - a RSCH is
                                        issued - a CSCH is issued Turned
                                        off when: - PAHIN receives a
                                        "final" interrupt. (Suspended
                                        NOP, or an interrupt for a
                                        non-suspended NOP, or CSCH.) Left
                                        on when: - PCI only interrupt is
                                        received.
          .1.. ....      EXPSUSPN       X'40' EXPSUSPN Indicates that the
                                        device is suspended and a RSCH is
                                        needed. Turned on when EXPINTE is
                                        turned off, and the device is
                                        suspended. Turned off when a RSCH
                                        or CSCH is issued.
          ..1. ....      EXPRSCHBC      X'20' EXPRSCHBC RSCH Bad
                                        Condition code. RSCH was issued
                                        but a CC1 or CC2 was received.
                                        Turned on when a RSCH is issued
                                        and results in a CC1 or a CC2.
                                        Turned off when an interrupt is
                                        received and PAH issues a SSCH to
                                        restart the previously built
                                        package.
          ...1 ....      EXPCSCHDN      X'10' EXPCSCHDN CSCH DoNe. Turned
                                        on when a CSCH is issued. Turned
                                        off when EXPINTE is turned off.
          .... 1...      EXPAQ          X'08' EXPAQ RAS: Call has been
                                        stacked to HCPPAUAQ after a RSCH
                                        CC=3.
          .... .1..      EXPNOPS        X'04' EXPNOPS RAS: Suspend is on
                                        in the final NOP CCW. Turned on
                                        when the final CCW has suspend
                                        indicated. Turned off when
                                        EXPINTE is turned off, or the the
                                        suspend bit is turned off and
                                        ESPSTAT2.DQINP is turned on.
          .... ..1.      EXPSSCHDN      X'02' EXPSSCHDN RAS: SSCH was
                                        stacked or gone to. Turned on
                                        when a SSCH is stacked. Turned
                                        off when EXPINTE is turned off.
          .... ...1      EXPRSCHDN      X'01' EXPRSCHDN RAS: RSCH was
                                        issued. Turned on when a RSCH is
                                        issued. Turned off when EXPINTE
                                        is turned off.
00B3  179 Bitstring    1 EXPSTAT2       Exposure status flag two
          1... ....      EXPDQINP       X'80' EXPDQINP Indicates a
                                        DEQUEUE in progress. Turned on
                                        when it is determined that a
                                        device needs to come to an
                                        unsuspended state. Turned off
                                        when EXPSTAT1.EXPINTE is turned
                                        off and the device is not
                                        suspended.
00B4  180 Signed       4 EXPLCKCS       CSGET lock, see also EXPCPUCS
      The PIOBK array (array of PIOBKs) contains the
      channel program for this exposure.  Therefore
      it is allocated below the 2G line.
      Most PIOBK "work" is done using host absolute addresses.
      Any reference to the "previous" PIOBK in the
      comments refers to the PIOBK that tics to a CCW
      within this PIOBK.  Any reference to the "next"
      PIOBK in the comments refers to the PIOBK that
      is TICed to by the TIC/NOP in this PIOBK.
      See PIOBK for more information concerning each PIOBK.
00B8  184 Address      4 EXPPIOARHL     PIOBK Array Host Logical. Host
                                        logical address of the array of
                                        PIOBKs.
00BC  188 Address      4 EXPPIOARHA     PIOBK Array Host Absolute. Host
                                        absolute address of the array of
                                        PIOBKs.
00C0  192 Address      4 EXPPIOAREND    PIOBK Array End. Host absolute
                                        address of the last byte of the
                                        array of PIOBKs.
00C4  196 Signed       4 *              Reserved for future IBM use.
       The "executing" PIOBKs for this exposure
      These next two pointers define the first through last PIOBKS
      that have been "sent" to the channel.  The second pointer
      is updated as the channel program is being built though.
      Initial state - PIOEF = PIOEL = First PIOBK in Array
                                      (Arbitrary, could be any)
      I/O Executing state - see comments below
      Suspended (idle) state - PIOEF=PIOEL (suspended PIOBK)
      Idle (Unsuspended) state - PIOEF = PIOEL (last processed)
      PIOEF and PIOEL will never be zero.
00C8  200 Address      4 EXPPIOEF       PIOBK Executing First. Host
                                        absolute address of the first
                                        executing PIOBK. This is the HA
                                        address of the PIOBK in the
                                        current channel program that has
                                        not been processed by HCPPAHIN
                                        (or is currently suspended).
                                        Note: In the case of a RSCH, this
                                        points to the PIOBK that is
                                        pointed into by the TIC that was
                                        resumed. In the case of a SSCH,
                                        this points to the PIOBK that has
                                        the Define Extent pointed to by
                                        CPA in the ORB. In the case when
                                        a PCI interrupt is received, this
                                        points to the next PIOBK that is
                                        not yet processed.
00CC  204 Address      4 EXPPIOEL       Executing Last. "Suspended" Host
                                        absolute address of the PIOBK in
                                        the executing channel program
                                        that contains the last R/W CCW
                                        and has (ends in) either a
                                        NOP/suspend, or a NOP.
00D0  208 Address      4 EXPGATE        This is the address of the PIOBK
                                        that was executed by the channel
                                        subsystem and has a suspended
                                        NOP. Set when construction of a
                                        new segment of channel program
                                        begins. Just before a segment is
                                        executed (SSCH or RSCH) the NOP
                                        in this PIOBK is changed to a TIC
                                        to the next appropriate CCW, and
                                        this field is set to 0. Its
                                        important this is not done
                                        earlier as the I/O subsystem may
                                        do a RSCH while we are still
                                        building the next CCW segment.
00D4  212 Signed       4 *              Reserved for IBM use
       The "built" PIOBKs for this exposure
      These next two pointers define the first through
      last PIOBKS that have unprocessed CCWs that have
      been built, but not yet sent to the channel.  When
      an SSCH is scheduled or a RSCH receives a CC0 then
      these built PIOBKs become the executing PIOBKs.
      Initial state - PIOBF = 0
                      PIOBL = 0
      Reset to initial state when a SSCH is
      scheduled, or a RSCH receives a CC0.
      BKT didn't actually use/need the first 2. To be deleted.
00D8  216 Address      4 EXPPIOBF       Built first. Host absolute
                                        address of the first PIOBK as a
                                        new channel program is being
                                        built. This PIOBK has a R/W CCW
                                        that is waiting to be executed.
                                        The "previous" PIOBK NOP address
                                        has been updated to point to the
                                        define extent, but is still a NOP
                                        (till just before SSCH or RSCH.)
                                        This field may be zero indicating
                                        a channel program is not
                                        currently being built.
00DC  220 Address      4 EXPPIOBL       Built last. Host absolute address
                                        of the last PIOBK as a new
                                        channel program is being built.
                                        This PIOBK has a R/W CCW that is
                                        waiting to be executed. The
                                        "previous" PIOBK TIC/NOP address
                                        has been updated to point to the
                                        define extent, locate record, or
                                        R/W and has been changed to a TIC
                                        unless this is also EXPPIOBF.
00E0  224 Address      4 EXPeffLR       Host absolute address of the
                                        PIOBK with the effective Locate
                                        record as a channel program is
                                        being built.
       The "available" PIOBKs for this exposure
      These next two pointers define the first
      through last PIOBKS that are available.
      These pointers may not be zero
      When EXPPIOAF and EXPPIOAL are equal, no PIOBKs are
      available (We can not use the last "available" one since
      it contains a TIC that the channel may want to look at
      if a RSCH is issued.  Think - Suspended, but idle case.)
      When all are available, then EXPPIOAL will be
      the PIOBK that tics into the PIOBK at EXPIOLAF.
      Initial state - EXPIOAF = EXPPIOARHA
                      EXPIOAL = HA Address of the last PIOBK
                                in the array.
      Full (no PIOBKs available) EXPIOAF=EXPIOAL
      BKT didn't actually use/need these two pointers.  to be ded.
00E4  228 Address      4 EXPPIOAF       Available First. Host absolute
                                        address of the first available
                                        PIOBK. This PIOBK has the
                                        processed flag on and is
                                        available to be used to build or
                                        continue building a channel
                                        program.
00E8  232 Address      4 EXPPIOAL       Available Last. Host absolute
                                        address of the last available
                                        PIOBK. This PIOBK has the
                                        processed flag on and is
                                        available to be used to build or
                                        continue building a channel
                                        program.
00EC  236 Signed       4 EXPAVAIL       Number of PIOBKs available. The
                                        number of PIOBKs available. The
                                        last one, must not be used, so
                                        this will bottom out at 1.
                                        (therefore, 1 => none
                                        available.)
00F0  240 Signed       4 EXPBUILT       Number of PIOBKs built.
00F4  244 Signed       4 EXPEXEC        Number of PIOBKs executing. Note:
                                        This is the number of outstanding
                                        read/write CCWs that have not
                                        been processed, but have been
                                        sent to the channel.
                                        (PIORDWRO.PIOFINIS=0) RAS. Debug
                                        only? BKT
00F8  248 Dbl-Word     8 EXPLRSAVES     Number of mid i/o Locate records
0100  256 Dbl-Word     8 EXPMAXED       Number of times we could have
                                        used more PIOBKs.
0108  264 Dbl-Word     8 EXPSTATS (9)   MinMaxAvg stats for number of
                                        PIOBKs in use at SSCH/RSCH time.
0150  336 Signed       4 *              Reserved for IBM use
      These are deferred saveareas when all CCW packages
      are in use for this exposure.  The queues are described
      in the general comments section of HCPPAGRV.
0154  340 Address      4 EXPSFDSV       First deferred savearea for
                                        single reads and writes. (A
                                        PPIBK)
0158  344 Address      4 EXPSLDSV       Last deferred savearea for single
                                        reads and writes. (A PPIBK)
015C  348 Signed       4 EXPCURQS       Count of deferred PPIBKs on
                                        EXPSFDSV each representing 1 page
                                        read or 1 page write.
0160  352 Address      4 EXPMRDFQ       Host logical address of the
0164  356 Signed       4 EXPCURQMR      PPIBK that contains the queue of
                                        deferred FRMTEs (PPIFRMQG) to be
                                        read for a multiple read request.
                                        Followed by the count of pages on
                                        that queue. Mapped by EXPQUENT
                                        DSECT.
0168  360 Address      4 EXPMWDFQ       Host logical address of the
016C  364 Signed       4 EXPCURQMW      PPIBK that contains the queue of
                                        deferred FRMTEs (PPIFRMQG) to be
                                        written for a multiple write
                                        request. Followed by the count of
                                        pages on that queue. Mapped by
                                        EXPQUENT DSECT.
0170  368 Signed       4 EXPRedriving   When we redrive a multi-read or
                                        multi-write we will move the
                                        count dequeued to here, and keep
                                        track of them. If we requeue left
                                        overs, after filling the PIOBK
                                        array, we will know how many are
                                        left.
0174  372 Bitstring    1 EXPPossArrow   A binary switch.
          1... ....      EXPWriteNext   X'80' EXPWriteNext Write next
                                        time.
          .... ....      EXPReadNext    X'00' EXPReadNext Read next time.
0175  373 Bitstring    3 *              Reserved for IBM use
0178  376 Signed       4 *              Reserved for IBM use
017C  380 Signed       4 *              Reserved for IBM use
      Monitor counters.
0180  384 Signed       2 *              Reserved for IBM use.
0182  386 Signed       2 EXPQCNEG       Number of times EXPCURQC went
                                        neg.
0184  388 Signed       4 EXPCURQC       Cardinal count of all outstanding
                                        paging/spooling reads/writes for
                                        this device. Used directly by
                                        Perfkit. Do not change offset.
0188  392 Signed       4 *              Reserved for IBM use
018C  396 Address      4 EXPPAGIOR      IORBK for this exposure. PAGBK
                                        for this exposure. The IORBK is
                                        always at the beginning of the
                                        PAGBK so this field does double
                                        duty.
0190  400 Signed       4 EXPCTUSI       Total count of the number of
                                        times the channel program had to
                                        be terminated to allow user I/O.
                                        This is an indicator of
                                        interference between user and
                                        paging/spooling I/O. Used
                                        directly by Perfkit. Do not
                                        change offset.
0194  404 Signed       4 EXPTIMER       Exposure timestamp for SSCH/RSCH.
0198  408 Signed       4 EXPINTIM       Exposure timestamp at I/O
                                        interrupt time.
019C  412 Signed       4 EXPNMPIO       Number of active PIOBKS at I/O
                                        interrupt time used to calc
                                        service time.
01A0  416 Signed       4 *              Reserved for IBM use
01A4  420 Signed       4 *              Reserved for IBM use
01A8  424 Signed       4 *              Reserved for future use.
01AC  428 Signed       4 EXPBKEND (0)   End of EXPBK.
          000001AC       EXPBSIZE       *-EXPBK Size of this DSECT in
                                        Bytes
          00000036       EXPSIZE        (((*-EXPBK)+7)/8) Size in
                                        double-words
      MLOAD constants
          00FFFFFF       EXPMXTOT       X'7FFFFFFF' Maximum total MLOAD
                                        value
          007FFFFF       EXPMXAVG       X'007FFFFF' Maximum average MLOAD
                                        value
      The next two statements EXPQUENT, and EXPQANCH
      are used to map the multiple read and
      write queue fields EXPMRDFQ and EXPMWDFQ.


 EXPQUENT DSECT
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Hex   Dec Type/Val   Lng Label (dup)    Comments
---- ---- --------- ---- -------------- --------
0000    0 Structure      EXPQUENT       Paging Information Header Block
0000    0 Address      4 EXPQANCH       Anchor for multiple defer queues.
0004    4 Signed       4 EXPCount       Count of pages on that queue.

          
*** EXPBK - Paging Information Header Block
*
*     +-------------------------------------------------------+
*   0 |                                                       |
*     =                       EXPPHDBK                        =
*     |                                                       |
*     +-------------+------+------+---------------------------+
*  B0 |  EXPCPUCS   |:STAT1|:STAT2|         EXPLCKCS          |
*     +-------------+------+------+---------------------------+
*  B8 |        EXPPIOARHL         |        EXPPIOARHA         |
*     +---------------------------+---------------------------+
*  C0 |       EXPPIOAREND         |///////////////////////////|
*     +---------------------------+---------------------------+
*  C8 |         EXPPIOEF          |         EXPPIOEL          |
*     +---------------------------+---------------------------+
*  D0 |         EXPGATE           |///////////////////////////|
*     +---------------------------+---------------------------+
*  D8 |         EXPPIOBF          |         EXPPIOBL          |
*     +---------------------------+---------------------------+
*  E0 |         EXPEFFLR          |         EXPPIOAF          |
*     +---------------------------+---------------------------+
*  E8 |         EXPPIOAL          |         EXPAVAIL          |
*     +---------------------------+---------------------------+
*  F0 |         EXPBUILT          |         EXPEXEC           |
*     +---------------------------+---------------------------+
*  F8 |                      EXPLRSAVES                       |
*     +-------------------------------------------------------+
* 100 |                       EXPMAXED                        |
*     +-------------------------------------------------------+
* 108 |                                                       |
*     =                       EXPSTATS                        =
*     |                                                       |
*     +---------------------------+---------------------------+
* 150 |///////////////////////////|         EXPSFDSV          |
*     +---------------------------+---------------------------+
* 158 |         EXPSLDSV          |         EXPCURQS          |
*     +---------------------------+---------------------------+
* 160 |         EXPMRDFQ          |        EXPCURQMR          |
*     +---------------------------+---------------------------+
* 168 |         EXPMWDFQ          |        EXPCURQMW          |
*     +---------------------------+------+--------------------+
* 170 |       EXPREDRIVING        |(174) |////////////////////|
*     +---------------------------+------+--------------------+
* 178 |///////////////////////////|///////////////////////////|
*     +-------------+-------------+---------------------------+
* 180 |/////////////|  EXPQCNEG   |         EXPCURQC          |
*     +-------------+-------------+---------------------------+
* 188 |///////////////////////////|        EXPPAGIOR          |
*     +---------------------------+---------------------------+
* 190 |         EXPCTUSI          |         EXPTIMER          |
*     +---------------------------+---------------------------+
* 198 |         EXPINTIM          |         EXPNMPIO          |
*     +---------------------------+---------------------------+
* 1A0 |///////////////////////////|///////////////////////////|
*     +---------------------------+---------------------------+
* 1A8 |///////////////////////////|
*     +---------------------------+
*
*** EXPBK - Paging Information Header Block
          
*** EXPQUENT - Paging Information Header Block
*
*     +---------------------------+---------------------------+
*   0 |         EXPQANCH          |         EXPCOUNT          |
*     +---------------------------+---------------------------+
*   8
*
*** EXPQUENT - Paging Information Header Block

 
Symbol         Dspl Value
-------------- ---- -----
EXPeffLR       00E0
EXPAQ          00B2 08
EXPAVAIL       00EC
EXPBKEND       01AC
EXPBSIZE       01AC 000001AC
EXPBUILT       00F0
EXPCount       0004
EXPCPUCS       00B0
EXPCSCHDN      00B2 10
EXPCTUSI       0190
EXPCURQC       0184
EXPCURQMR      0164
EXPCURQMW      016C
EXPCURQS       015C
EXPDQINP       00B3 80
EXPEXEC        00F4
EXPGATE        00D0
EXPIDLE        00B2 00
EXPINTE        00B2 80
EXPINTIM       0198
EXPLCKCS       00B4
EXPLRSAVES     00F8
EXPMAXED       0100
EXPMRDFQ       0160
EXPMWDFQ       0168
EXPMXAVG       01AC 007FFFFF
EXPMXTOT       01AC 00FFFFFF
EXPNMPIO       019C
EXPNOPS        00B2 04
EXPPossArrow   0174
EXPPAGIOR      018C
EXPPHDBK       0000
EXPPIOAF       00E4
EXPPIOAL       00E8
EXPPIOAREND    00C0
EXPPIOARHA     00BC
EXPPIOARHL     00B8
EXPPIOBF       00D8
EXPPIOBL       00DC
EXPPIOEF       00C8
EXPPIOEL       00CC
EXPQANCH       0000
EXPQCNEG       0182
EXPReadNext    0174 00
EXPRedriving   0170
EXPRSCHBC      00B2 20
EXPRSCHDN      00B2 01
EXPSFDSV       0154
EXPSIZE        01AC 00000036
EXPSLDSV       0158
EXPSSCHDN      00B2 02
EXPSTATS       0108
EXPSTAT1       00B2
EXPSTAT2       00B3
EXPSUSPN       00B2 40
EXPTIMER       0194
EXPWriteNext   0174 80