HALBK Back to Index page
 
Prolog 
Control Block Contents 
   HALBK 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.


  HALBK Prolog Top of page
 
 NAME       : HCPHALBK
 DESCRIPTION: Host-ART lookaside block
 DSECT      : HALBK
 FUNCTION   : The HALBK maps ALETs to I-ASITs for
              host-access-register translation.
 SERIALIZED : Each task is responsible for its own
              serialization
 RELOCATION CONSIDERATIONS : None
 COMMENTS   : This block is meant to be used with the
              HCPHALM macro. The user must:
              - acquire HALBK storage
              - have an active HCPUSING on the block
              - fill in the header.
              Then HCPHALM may be used to search and
              manipulate entries in this block.
              The count of the number of entries in the HALBK
              must fit in a fullword; that's the only
              restriction on HALBK size. If, however, the
              total size of the HALBK (header + (entry length
              * number of entries)) could be greater than
              509 doublewords, the PAGES=DECIDE option should
              be used on the HCPGETST and HCPRELST macros.
 
 
  HALBK Control Block Content Top of page
 

 HALBK DSECT Top of page
Hex Dec Type/Val Lng Label (dup) Comments ---- ---- --------- ---- -------------- -------- 0000 0 Structure HALBK Host-ART lookaside block 0000 0 Character 16 HALHDR HALBK header 0010 16 Character 16 HALENTRY HALBK entry (there can be more than one of these). Mapping of the HALBK header 0000 0 Signed 4 HALMXENT Maximum number of HALBK entries 0004 4 Address 4 HALVMDBK Address of the base VMDBK associated with the access list to which the ALETs belong. 0008 8 Character 8 * Reserved for IBM use. Mapping of HALBK entries 0010 16 Bitstring 1 HALSTATE State flag for the entry 00000000 HALINVAL X'00' HALINVAL The entry is invalid (does not contain an ALET/i-ASIT pair). 00000001 HALVALID X'01' HALVALID The entry is valid (does contain an ALET/i-ASIT pair). 0011 17 Bitstring 3 * Reserved for IBM use 0014 20 Signed 4 HALALET ALET 0018 24 Character 8 HALIASIT I-ASIT associated with HALALET 0020 32 Signed 4 HALNEXT (0) Next entry in the list Length equate 00000004 HALSIZE (*-HALBK+7)/8 Length of HALBK in DWs
 
 
  HALBK Storage Layout Top of page
 
          
*** HALBK - Host-ART lookaside block
*
*     +-------------------------------------------------------+
*   0 |                        HALHDR                         |
*     |                                                       |
*     +-------------------------------------------------------+
*  10 |                       HALENTRY                        |
*     |                                                       |
*     +-------------------------------------------------------+
*  20
*
*** HALBK - Host-ART lookaside block
          
*** Overlay for HALHDR in HALBK
*
*     +---------------------------+---------------------------+
*   0 |         HALMXENT          |         HALVMDBK          |
*     +---------------------------+---------------------------+
*   8 |///////////////////////////////////////////////////////|
*     +-------------------------------------------------------+
*  10
*
*** Overlay for HALHDR in HALBK
          
*** Overlay for HALENTRY in HALBK
*
*     +------+--------------------+---------------------------+
*  10 |:STATE|////////////////////|         HALALET           |
*     +------+--------------------+---------------------------+
*  18 |                       HALIASIT                        |
*     +-------------------------------------------------------+
*
*** Overlay for HALENTRY in HALBK
 
 
  HALBK Cross Reference Top of page
 
 
Symbol         Dspl Value
-------------- ---- -----
HALALET        0014
HALENTRY       0010
HALHDR         0000
HALIASIT       0018
HALINVAL       0010 00000000
HALMXENT       0000
HALNEXT        0020
HALSIZE        0020 00000004
HALSTATE       0010
HALVALID       0010 00000001
HALVMDBK       0004
 
This information is based on z/VM 7.3.0 Last updated on 22 Jun 2022 at 15:50:59 EDT.
Copyright IBM Corporation, 1990, 2022