CHCBK

Prolog  

Control Block Contents  
   CHCBK DSECT

Storage Layout  

Cross Reference (Contains links to field and bit definitions)  

CHCBK Prolog

 NAME       : HCPCHCBK
 DESCRIPTION: CHANNEL CLASS BLOCK
 DSECT      : CHCBK
 FUNCTION   : DESCRIBE THE STATUS OF THE CHANNELS ( IN XA MODE, THE
              CHANNEL CLASSES) FOR A VIRTUAL MACHINE.
              ANCHOR THE QUEUE OF DEVICES (FOR EACH CHANNEL NUMBER OR
              CLASS) FOR WHICH INTERRUPTS ARE PENDING.
 LOCATED BY : VMDCHC FIELD IN THE VIRTUAL MACHINE'S DEFINITION BLOCK
 CREATED BY : VIRTUAL MACHINE CREATION PROCESS - HCPBVM
 DELETED BY : VIRTUAL MACHINE DESTRUCTION PROCESS

CHCBK Control Block Content

CHCBK DSECT

Hex   Dec Type/Val   Lng Label (dup)    Comments
---- ---- --------- ---- -------------- --------
0000    0 Structure      CHCBK          CHANNEL CLASS BLOCK
0000    0 Dbl-Word     8 CHCLOCK (0)    LOCKWORD FOR THIS BLOCK
0000    0 Address      4 CHCLOWNR       ADDRESS OF OWNING VMDBK
0004    4 Address      4 CHCLOCWQ       QUEUE OF WAITING TASKS
0008    8 Signed       4 *              Reserved for future IBM use
     SET-CHANNEL-MONITOR DOUBLEWORD THE FOLLOWING FIELDS CONTROL GUEST
     CHANNEL MONITORING. THEY ARE KEPT WITHIN A DOUBLEWORD TO ALLOW A
     STORE-MULTIPLE TO PERFORM MP-CONSISTENT SETTING OF THE CONTROLS ON A
     HOST MP.
000C   12 Signed       4 CHCKEYCN (0)   Key and control word
000C   12 Bitstring    1 CHCKEY         KEY OF USER MEASUREMENT BLOCK
000D   13 Bitstring    1 *              RESERVED FOR FUTURE IBM USE
000E   14 Bitstring    1 *              RESERVED FOR FUTURE IBM USE
000F   15 Bitstring    1 CHCHFLAG       HARDWARE CONTROLS
          .... ..1.      CHCMSM         X'02' MEASUREMENT ACTIVE
          .... ...1      CHCTIM         X'01' TIMING (SHOULD BE) ACTIVE
0010   16 Dbl-Word     8 CHCGMBO (0)    ESAME: 64 bit MBO for monitoring
0010   16 Signed       4 CHCGMBOH       ESAME: high order MBO word
0014   20 Signed       4 CHCGMBOL       ESAME: Low order MBO word
          ...1 .1..      CHCMBLKO       CHCGMBOL 390: Measurement Blk
                                        Origin
0018   24 Signed       4 CHCIORW        POINTER TO CHAIN OF CRWBK'S.
001C   28 Bitstring    1 CHCSFLAG       SOFTWARE CONTROLS
          1... ....      CHCRWCC1       X'80' CONDITION CODE 1 REMAINS TO
                                        BE GIVEN TO A GUEST STORE CHANNEL
                                        REPORT WORD SINCE GENERATING A
                                        MACHINE CHECK FOR A PREVIOUS
                                        CHANNEL REPORT WORD CONDITION.
                                        THIS BIT IS CLEARED BY AN I/O
                                        SYSTEM RESET. IT PREVENTS THE
                                        GENERATION OF A MACHINE CHECK FOR
                                        CHANNEL REPORT WORDS MADE
                                        PENDING.
001D   29 Bitstring    1 *              RESERVED FOR FUTURE IBM USE
001E   30 Bitstring    1 *              RESERVED FOR FUTURE IBM USE
001F   31 Bitstring    1 *              RESERVED FOR FUTURE IBM USE
0020   32 Signed       4 CHCSALIM       SET ADDRESS LIMIT VALUE
0024   36 Signed       4 CHCMCV         POINTER TO MCVBK. FOR FLOATING
                                        MACHINE CHECKS (THEY ARE RELATED
                                        TO THE I/O SUBSYSTEM).
0028   40 Signed       4 *              RESERVED FOR FUTURE IBM USE
002C   44 Signed       4 *              RESERVED FOR FUTURE IBM USE
0030   48 Signed       4 *              RESERVED FOR FUTURE IBM USE
0034   52 Signed       4 CHCIOPND       MASK OF PENDING INTERRUPTIONS
0038   56 Dbl-Word     8 CHCQUEUE (32)  FWD AND BWD INTERRUPT PTRS
          00000020       CHCQSIZE       (*-CHCQUEUE)/CHCQENTL DEFINE
                                        NUMBER OF CHANNELS
          00000027       CHCSIZE        (*-CHCBK+7)/8 SIZE OF FLOATING
                                        CHANNEL BLOCK
0038   56 Signed       4 CHCQUEFW       CHANNEL INT. QUEUE FORWARD PTR
003C   60 Signed       4 CHCQUEBW       CHANNEL INT. QUEUE BACKWARD PTR
          00000008       CHCQENTL       *-CHCQUEFW LENGTH OF QUEUE
                                        POINTERS

CHCBK Storage Layout

          
*** CHCBK - CHANNEL CLASS BLOCK
*
*     +---------------------------+---------------------------+
*   0 |         CHCLOWNR          |         CHCLOCWQ          |
*     +---------------------------+------+------+------+------+
*   8 |///////////////////////////|CHCKEY|//////|//////|:HFLAG|
*     +---------------------------+------+------+------+------+
*  10 |         CHCGMBOH          |         CHCGMBOL          |
*     +---------------------------+------+------+------+------+
*  18 |         CHCIORW           |:SFLAG|//////|//////|//////|
*     +---------------------------+------+------+------+------+
*  20 |         CHCSALIM          |          CHCMCV           |
*     +---------------------------+---------------------------+
*  28 |///////////////////////////|///////////////////////////|
*     +---------------------------+---------------------------+
*  30 |///////////////////////////|         CHCIOPND          |
*     +---------------------------+---------------------------+
*  38 |                                                       |
*     =                       CHCQUEUE                        =
*     |                                                       |
*     +-------------------------------------------------------+
* 138
*
*** CHCBK - CHANNEL CLASS BLOCK
          
*** Overlay for CHCQUEUE in CHCBK
*
*     +---------------------------+---------------------------+
*  38 |         CHCQUEFW          |         CHCQUEBW          |
*     +---------------------------+---------------------------+
*  40
*
*** Overlay for CHCQUEUE in CHCBK

CHCBK Cross Reference

Symbol         Dspl Value
-------------- ---- -----
CHCGMBO        0010
CHCGMBOH       0010
CHCGMBOL       0014
CHCHFLAG       000F
CHCIOPND       0034
CHCIORW        0018
CHCKEY         000C
CHCKEYCN       000C
CHCLOCK        0000
CHCLOCWQ       0004
CHCLOWNR       0000
CHCMBLKO       0014 14
CHCMCV         0024
CHCMSM         000F 02
CHCQENTL       003C 00000008
CHCQSIZE       0038 00000020
CHCQUEBW       003C
CHCQUEFW       0038
CHCQUEUE       0038
CHCRWCC1       001C 80
CHCSALIM       0020
CHCSFLAG       001C
CHCSIZE        0038 00000027
CHCTIM         000F 01