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

#### GALPL

Prolog

Control Block Contents
GALPL DSECT

Storage Layout

Cross Reference (Contains links to field and bit definitions)

#### GALPL Prolog

     NAME       : HCPGALPL
     DESCRIPTION: Generalized Associative Lookup
                  Parameter List
     DSECT      : GALPL
     FUNCTION   : Provide the parameters, work area and root for
                  hash table used by HCPGAL
     LOCATED BY : N/A
     CREATED BY : A program that needs it.
                  It may also be permanently defined in a
                  data module such as in HCPHSH.
     DELETED BY : A program when function not needed.
                  It may also never be deleted even when all
                  the entries have been deleted.  This is the
                  case for the data module HCPHSH.
     COMMENTS   : This parameter list is used by the generalized
                  associative lookup routine to both define a
                  hash table and store its high level index
                  The caller is responsible for defining the size
                  of the key (GALKEYSZ) and providing sufficient
                  space for the high level index (GALINDX)
                  The remaining fields are work areas.

#### GALPL Control Block Content

#### GALPL DSECT

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      GALPL          Generalized Associative Lookup
                                           parameters
    0000    0 Signed       4 GALLOCK        Hash table lock
    0004    4 Signed       4 GALCNUM        The number of entries currently
                                            in the hash table
    0008    8 Signed       4 GALCCAP        The current capacity of the hash
                                            table in slots
    000C   12 Signed       4 GALEC          Total number of searches
    0010   16 Signed       4 GALPC          Total number of probes
                                            GALPC/GALEC = probes per search
    0014   20 Signed       4 GALTHRSH       The number of hash entries beyond
                                            which the table must grow by a
                                            page
    0018   24 Signed       2 GALNEWPI       Offset to position in high level
                                            index for new hash page address
    001A   26 Bitstring    1 GALKEYSZ       The number of bytes in the key
    001B   27 Character   89 GALWORK        Workarea for HCPGAL entry pts
    0074  116 Signed       4 GALENDWD       Last word in GALINDX
              00000078       GALLENTH       *-GALPL Size of header in bytes
    0078  120 Signed       4 GALINDX (0)    High level index area NB: There
                                            must be one word here for every
                                            750 entries that can be in the
                                            largest possible hash table. The
                                            actual number is 763.5 but we
                                            allow a little breathing room.
                                            This number is 75% of the number
                                            of 4-byte entries that fit in a
                                            page minus 24 bytes or
                                            ((4096-24)/4*(.75)) entries.

#### GALPL Storage Layout

    *** GALPL - Generalized Associative Lookup
    *
    *     +---------------------------+---------------------------+
    *   0 |         GALLOCK           |         GALCNUM           |
    *     +---------------------------+---------------------------+
    *   8 |         GALCCAP           |          GALEC            |
    *     +---------------------------+---------------------------+
    *  10 |          GALPC            |         GALTHRSH          |
    *     +-------------+------+------+---------------------------+
    *  18 |  GALNEWPI   |:KEYSZ|                                  |
    *     +-------------+------+                                  |
    *  20 |                                                       |
    *     =                       GALWORK                         =
    *     |                           +---------------------------+
    *  70 |                           |         GALENDWD          |
    *     +---------------------------+---------------------------+
    *
    *** GALPL - Generalized Associative Lookup

#### GALPL Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    GALCCAP        0008
    GALCNUM        0004
    GALEC          000C
    GALENDWD       0074
    GALINDX        0078
    GALKEYSZ       001A
    GALLENTH       0074 00000078
    GALLOCK        0000
    GALNEWPI       0018
    GALPC          0010
    GALTHRSH       0014
    GALWORK        001B

This information is based on z/VM V6R1.0. Last updated on 18 Feb 2010 at 09:08:06 EDT.
Copyright IBM Corporation, 1990, 2008