SYMTB | Back to Index page

| Prolog Control Block Contents SYMTB 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.

SYMTB Prolog | Top of page

     NAME       : HCPSYMTB
     DESCRIPTION: Symbol Table Entry
     DSECT      : SYMTB
     FUNCTION   : The Symbol Table Entry contains information to
                  describe the location, size and (possibly) attributes
                  of CP external labels.
     LOCATED BY : SYMPT, LOCATE process pointer blocks.
     CREATED BY : HCPCFD   as a result of a dynamic load as a result
                  of CPXLOAD.
                  HCPLDR   during the CP nucleus build process.
     DELETED BY : HCPCFD   as a result of a dynamic unload of executable
                  code.
     REFERENCES : None
     SERIALIZED : Additions or changes to the SYMTB entries is controlled
                  by the SYMLHLCK lock.
     RELOCATION CONSIDERATIONS : None
     NOTES      : SYMTB entries never exist alone, they are always part
                  of @MAPSTRT-@MAPEND set of SYMTB entries, or are part
                  of a page of SYMTB entries created by HCPCFDAD during
                  normal system operation as a result of CPXLOAD.

SYMTB Control Block Content | Top of page

     SYMTB DSECT
    Top of page

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      SYMTB          Symbol Table Entry
    0000    0 Character    8 SYMTBNM        Symbol name
    0008    8 Address      4 SYMTBVA        Virtual address in CP
    000C   12 Bitstring    1 SYMTBF0        Flags
              1... ....      SYMTBF0L       X'80' SYMTBF0L Added by HCPCFDAD
    000D   13 Signed       3 SYMTBLN        Length (if CSECT), else 0
          The SYMTB described up to this point is the portion (16
          bytes) of the SYMTB built by HCPLDR and cannot be changed
          unless HCPLDR is radically changed.
          The only way to realize that no additional fields exist
          is to realize that this SYMTB is located by the first
          SYMPT pointer block that is chained from the SYMLH Locate
          Header Block.
          SYMTBSSZ is the length of these static entries built by
          HCPLDR.
              00000010       SYMTBSSZ       *-SYMTB Length of SYMTB entries
                                            for @MAPSTRT entries
          These additional fields are built only for SYMTB entries
          added during normal system operation by HCPCFDAD when new
          external labels come into existence, like during dynamic
          loading of executable code from CMS files.
          The way to realize that these additional fields exist is
          to test SYMTBF0.SYMTBF0L, which indicates that this SYMTB
          describes external labels in dynamically loaded modules.
    0010   16 Bitstring    1 SYMTBF1        Flags
    0011   17 Bitstring    1 SYMTBF2        Flags
    0012   18 Bitstring    1 SYMTBF3        Flags
    0013   19 Bitstring    1 SYMTBF4        Flags
              .1.. ....      SYMTBF4T       X'40' SYMTBF4T Loaded TEMPORARY
                                            SYMTBDSZ is the length of the
                                            dynamic entries built by HCPCFD.
    0014   20 Signed       4 * (0)          Assure fullword alignment
              00000014       SYMTBDSZ       *-SYMTB Length of SYMTB entries
                                            for dynamic entries

SYMTB Storage Layout | Top of page

    *** SYMTB - Symbol Table Entry
    *
    *     +-------------------------------------------------------+
    *   0 |                       SYMTBNM                         |
    *     +---------------------------+------+--------------------+
    *   8 |         SYMTBVA           |:TBF0 |      SYMTBLN       |
    *     +------+------+------+------+------+--------------------+
    *  10 |:TBF1 |:TBF2 |:TBF3 |:TBF4 | 14
    *     +------+------+------+------+
    *
    *** SYMTB - Symbol Table Entry

SYMTB Cross Reference | Top of page

    Symbol         Dspl Value
    -------------- ---- -----
    SYMTBDSZ       0014 00000014
    SYMTBF0        000C
    SYMTBF0L       000C 80
    SYMTBF1        0010
    SYMTBF2        0011
    SYMTBF3        0012
    SYMTBF4        0013
    SYMTBF4T       0013 40
    SYMTBLN        000D
    SYMTBNM        0000
    SYMTBSSZ       000D 00000010
    SYMTBVA        0008

This information is based on z/VM 7.2.0 Last updated on 24 Jun 2020 at 09:31:00 EDT.
Copyright IBM Corporation, 1990, 2020