1
2
3
4-15 ftegDi.ng If 1, this entry corresponds to a CSECT that has been previously
defined. All TXT cards and RLD cards referring to this CSECT in
this text deck should be ignored.
If 1, this entry corresponds to a CSECT definition (SD). Waiting ESD itells exist for this ESDID. Unused. REFTBL entry number (for example 1, 2, 3, etc.)
Bit 1 is very crucial because it is necessary to use the VALUE field
of the REFTBL if the ID corresponds to an ER, Cft, or FR; but, the INFO field of the REFTBL entry must be used in the ID corresponds to an SD. REFTBI. EntA:Y I 10(0) - - - - - - HAftE 8 (8) 19 (9)
FLAG1 , INFO I 12 (C) 113 (D) NOTEl I VALUE 1 16 (10) 117(11) FLAG2 1 ADDRESS A REFTBL entry is 20 bytes. The fields have the following uses: !AftE Contains the symbolic name from the ESD data item.
Loader 7C
7D
7E
7F 80 81
82
83 90 ESD 00 01 03 07 05 04 02 05 06 Routine XBYTE XfiALF XFULL XDBL XUNDEF XCXD XCOMSET iEAKEXT CTLLIB PR - byte alignment PR - halfword alignment PR - fullword alignment PR - doubleword alignment Undefined symbol
Resolve CXD Define common area
Weak external reference TXTLIBs not to be used to resolve names !!FO Depends upon the type of the ESD item. ESD Item SD (CSECT or START) LD (ENTRY) eft (COftMON) PR (Psuedo Register) INFO Field Relocation factor
Zero
Maximum length
2-84 IBM VM/370 System Logic and Program Determination--Volume 2
depends upon the type of the ESD item, as does the IBPO field. ESD Item VALUE Field SD (CSECT or START) lbsolue address
Absolue address
Absolue address
Assigned value
(starting fro. 0) LD (ENTRY) CM (COftMON) PR (Pseudo register)
FLAG2 Byte 0 Unused i Unused 2 Unused 3 Unused It!! l1§ni]!g 4 Unused 5 Name was located in a TITLIB
6 Section definition entry
7 Name specifically loaded from co •• and line.
Entries may be created in the loader reference table prior to tbe
actual defining of the symbol. For example, an entry is created for a
symbol if it is referenced by means of an EITRN (ER) even if the symbol
has not yet been defined or its type known. Furthermore, coa.on (CM) is
not assigned absolute addresses until prior to the start of execution by
the START command. These circumstances are determined by the setting of the flag byte;
if the symbol's value has not yet been defined, the value field
specifies the address of a patch control block (PCB). PATCH CONTROL BLOCK (PCB) These are allocated from free storage and pointed at from REFTBL entries
or other PCBs. Mea.!!i.!!.9 Address of next PCB 5-7 Location of ADCON in storage
4 Flag byte
All address constant locations in loaded program for undefined syabols are placed on PCB chains. LOADER INPUT RESTRICTIONS All restrictions which apply to object files for the as linkage editor
apply to CMS loader input files. Processing Commands that Manipulate the File System
Figure 9 lists the CMS modules that perfora either general file systea support functions or that perform data manipulation. CftS Method of Operation and Program Organization 2-85
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