Programming Interface Information:
This information is NOT intended to be used as Programming Interfaces of z/VM. |
SYMTB
Control Block Contents
SYMTB DSECT
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 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
*** 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
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