Programming Interface Information: This information is NOT intended to be
used as Programming Interfaces of z/VM.

HALBK

Prolog  

Control Block Contents  
   HALBK DSECT

Storage Layout  

Cross Reference (Contains links to field and bit definitions)  


HALBK Prolog

 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
 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


HALBK DSECT

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' The entry is invalid (does
                                        .not contain an ALET/i-ASIT
                                        .pair).
          00000001       HALVALID       X'01' The entry is valid (does
                                        .contain an ALET/i-ASIT .pair).
          00000000       *
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

          
*** 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

Symbol         Dspl Value
-------------- ---- -----
*              0010 00000000
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 V4R1.0.
Last updated on 6 Jun 2001 at 11:38:19 EDT.
Copyright IBM Corporation, 1990, 2001