SYMTB Back to Index page
Control Block Contents 
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
 DESCRIPTION: Symbol Table Entry
 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
 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 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 6.3.0 Last updated on 22 May 2013 at 13:55:56 EDT.
Copyright IBM Corporation, 1990, 2013