LATBK Back to Index page
 
Prolog 
Control Block Contents 
   LATBK DSECT
Storage Layout 
Cross Reference (Contains links to field and bit definitions)
Programming Interface Information:
This information is NOT intended to be
used as Programming Interfaces of z/VM.


  LATBK Prolog Top of page
  
 NAME       : HCPLATBK
 DESCRIPTION: C System Services Latch block
 DSECT      : LATBK
 FUNCTION   : C System Services Latch block used to describe the
              suspend lock used by platform specific C Services
 LOCATED BY : Passed as argument on latch, unlatch, testLatch
              and eventWait services
 CREATED BY : allocateLatch service
 DELETED BY : deallocateLatch service
 SERIALIZED : None
 RELOCATION CONSIDERATIONS : None
 NOTES      : This COPY file is modeled after HCPLKWRD so
              existing CP lock routines could be utilized.
 
 
  LATBK Control Block Content Top of page
  




 LATBK DSECT
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Hex   Dec Type/Val   Lng Label (dup)    Comments
---- ---- --------- ---- -------------- --------
0000    0 Structure      LATBK          C System Services Latch block
0000    0 Dbl-Word     8 LATCSWAP (0)   Doubleword updated by Compare and
                                        Swap
0000    0 Signed       4 LATSTATE       Current lock state.
0004    4 Address      4 LATQUEUE       Pointer to chain of deferred
                                        CPEBK's
0008    8 Signed       8 LATQQTOD       TOD saved at last
                                        enqueue/dequeue. (Only stamped if
                                        there's a queue.)
0010   16 Bitstring    1 LATFLG1        Miscellaneous lock flags (not
                                        used in C code - for CP
                                        compatibility)
0011   17 Bitstring    3 LATDQLEN       Current length of defer queue.
0014   20 Signed       4 LATDYTOD       TOD saved at start of last
                                        "delay"
0018   24 Address      8 LATTHRED       Pointer to thread which holds
                                        latch
          00000020       LATBSIZE       *-LATBK size in bytes
          00000004       LATSIZE        (*-LATBK+7)/8 size in double
                                        words
 
 
  LATBK Storage Layout Top of page
  
 
*** LATBK - C System Services Latch block
*
*     +---------------------------+---------------------------+
*   0 |         LATSTATE          |         LATQUEUE          |
*     +---------------------------+---------------------------+
*   8 |                       LATQQTOD                        |
*     +------+--------------------+---------------------------+
*  10 |:FLG1 |     LATDQLEN       |         LATDYTOD          |
*     +------+--------------------+---------------------------+
*  18 |                       LATTHRED                        |
*     +-------------------------------------------------------+
*  20
*
*** LATBK - C System Services Latch block
 
 
  LATBK Cross Reference Top of page
  
 
Symbol         Dspl Value
-------------- ---- -----
LATBSIZE       0018 00000020
LATCSWAP       0000
LATDQLEN       0011
LATDYTOD       0014
LATFLG1        0010
LATQQTOD       0008
LATQUEUE       0004
LATSIZE        0018 00000004
LATSTATE       0000
LATTHRED       0018
 
This information is based on z/VM 6.4.0 Last updated on 24 Aug 2016 at 09:25:56 EDT.
Copyright IBM Corporation, 1990, 2016