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

SYMTB

Prolog  

Control Block Contents  
   SYMTB DSECT

Storage Layout  

Cross Reference (Contains links to field and bit definitions)  


SYMTB Prolog

 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.
 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


SYMTB DSECT

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' 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' Loaded TEMPORARY
0014   20 Signed       4 * (0)          Assure fullword alignment
          00000014       SYMTBDSZ       *-SYMTB Length of SYMTB entries .
                                        for dynamic entries

 

SYMTB Storage Layout

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

 

SYMTB Cross Reference

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 V4R1.0.
Last updated on 5 Jun 2001 at 16:53:58 EDT.
Copyright IBM Corporation, 1990, 2001