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DECsystem-10 RPGII Internal Documentation
Date: 8 March 1977
Revision: 2
Copyright (C) 1976, 1977
Cerritos Community College District and Robert Currier
This software is furnished under license for use only on a single
computer system and may be copied only with the inclusion of the above
copyright notice. This software, or any other copies thereof, may not
be provided or otherwise made available to any other person except for
use on such system and to one who agrees to these license terms.
Title to and ownership of the software shall at all times remain with
Cerritos Community College District and Robert Currier.
The information in this software is subject to change without notice
and should not be construed as a commitment by either Cerritos
Community College District or Robert Currier.
RPGII Internal Documentation Page 2
Table of Contents
INTRODUCTION
CHAPTER 1 COMPILER OVERVIEW
1.1 COMPONENTS OF RPG II .................... 1-1
CHAPTER 2 COMPILER FILE STRUCTURE
2.1 CONTENTS OF SRC ......................... 2-2
2.2 CONTENTS OF LST ......................... 2-2
2.3 CONTENTS OF BIN ......................... 2-2
2.4 CONTENTS OF ERA ......................... 2-2
2.5 CONTENTS OF GEN ......................... 2-3
2.5.1 Operators ............................ 2-3
2.5.2 Operands, Other than Literal ......... 2-3
2.5.3 Operands, Literal .................... 2-3
2.6 CONTENTS OF CPY ......................... 2-3
2.7 CONTENTS OF CAL ......................... 2-4
2.8 CONTENTS OF AS1, AS2, AS3 ............... 2-4
2.8.1 Addresses ............................ 2-4
2.8.2 Address Increments ................... 2-4
2.8.3 Instructions ......................... 2-5
2.8.4 Byte Pointers ........................ 2-5
2.8.5 XWD .................................. 2-6
2.8.6 Constants ............................ 2-6
2.8.7 Miscellaneous ........................ 2-6
2.8.8 Instruction Codes .................... 2-7
CHAPTER 3 COMPILER INTERNAL TABLE STRUCTURE
3.1 FILTAB - THE FILE TABLE ................. 3-1
3.2 DATAB - THE DATA ITEM TABLE ............. 3-3
3.3 IDTTAB - THE INDICATOR CHAIN TABLE ...... 3-6
3.4 PROTAB - THE TAG TABLE .................. 3-7
3.5 LITAB - THE LITERAL TABLE ............... 3-7
3.6 VALTAB - THE VALUE TABLE ................ 3-8
3.7 NAMTAB - THE NAME TABLE ................. 3-8
3.8 EXTAB - THE EXTERNAL NAME TABLE ......... 3-8
CHAPTER 4 RUNTIME SYSTEM OVERVIEW
4.1 COMPONENTS OF RPGLIB .................... 4-1
4.2 INPUT/OUTPUT IN RPGLIB .................. 4-2
4.2.1 RPGIO ................................ 4-2
4.2.2 CBLIO ................................ 4-2
CHAPTER 5 RUNTIME SYSTEM INTERNAL TABLE STRUCTURE
5.1 CHNTAB - THE CHANNEL TABLE .............. 5-1
5.2 OTFTAB - THE OBJECT TIME FILE TABLE ..... 5-2
5.3 FTBTAB - THE CBLIO FILE TABLE ........... 5-3
5.4 ICHTAB - THE INPUT CHAIN TABLE .......... 5-6
RPGII Internal Documentation Page 3
5.5 OCHTAB - THE OUTPUT CHAIN TABLE ......... 5-8
5.6 ARRTAB - THE ARRAY TABLE ................ 5-9
APPENDIX A REFERENCE TABLES
A.1 INDICATOR VALUES ........................ A-1
RPGII Internal Documentation Page 4
Introduction
This manual is intended to assist the programmer that must maintain or
modify the DECsystem-10 RPGII system. While all attempts have been
made to assure the accuracy of this manual, the final authority is
always the program listings themselves. This manual is designed to be
used in conjunction with a set of listings, rather than just by
itself. In appropriate parts, references have been made to particular
program modules that contain further documentation of a particular
feature.
Programmers that are familiar with the DECsystem-10 COBOL system will
notice many similarities in RPGII. This is both good and bad. The
programmer that has been deep into COBOL and found his way out, should
not get lost in the RPGII system. However, such a programmer, being
overly smug about having a vague understanding of how COBOL works, may
get overconfident and not notice some of the subtle changes that have
been made. Contrary to appearences, these changes have not been made
just to trap unwary programmers, but were made for what, at the time,
seemed to be good reasons.
CHAPTER 1
COMPILER OVERVIEW
The RPG II compiler consists of seven major phases:
RPGIIA Initialization
RPGIIB Header, File, Extension and Line counter
specification scanner
RPGIIC Input and Output specification scanner
RPGIID Calculation specification scanner
RPGIIE Table builder and code generator
RPGIIF Listing
RPGIIG Final assembly
In addition there is a phase which dumps core and the contents of the
scratch files whenever a catastrophic error occurs in the compiler.
This phase in RPGIIK.
If a multi-segment compiler (ONESEG=0) is generated, the seven major
phases and RPGIIK are grouped into six high segments:
RPGII.SHR RPGIIA, RPGIIB
RPGIIC.SHR RPGIIC
RPGIID.SHR RPGIID
RPGIIE.SHR RPGIIE
RPGIIF.SHR RPGIIF, RPGIIG
RPGIIK.SHR RPGIIK
If a single segment compiler (ONESEG=1) is generated, all eight phases
are stored in RPGII.SHR.
1.1 COMPONENTS OF RPG II
Each phase of the compiler also contains an impure segment
(IMPURE.MAC) and one or more of the following routines. All of these
routines are collected into the library LIBA.REX. The extenstion of
"REX" is for historical reasons.
CLEANT Clean up tables to gain more free core
DIAGS Define diagnostics tables
GENCOM Common routines used by Phase E
COMPILER OVERVIEW Page 1-2
GETASY Read from AS1FIL, AS2FIL, AS3FIL
GETCPY Read from CPYFIL
GETERA Read from ERAFIL
GETGEN Read from GENFIL
GETSRC Read from the source file and perform some
editing
IMPURE Define the impure storage area
INTERM Universal file to define default switches
LOOKUP Generate code for the LOOKUP operation
PREDIT Pre-edit the edit words
PURAB Pure constants for Phases A & B
PUREC Pure constants for Phase C (multi-segment
compilers only)
PURED Pure constants for Phase D (multi-segment
compilers only)
PUREE Pure constants for Phase E (multi-segment
compilers only)
PURFG Pure constants for phases F & G
PUTAS1 Write AS1FIL
PUTAS2 Write AS2FIL
PUTAS3 Write AS3FIL
PUTBIN Write BINFIL
PUTERA Write ERAFIL
PUTGEN Write GENFIL
PUTLST Write LSTFIL
RPGASM Universal file to define option switches
RPGCOM Common routines used by all phases
RPGERR Define error messages
RPGIIA Initialization and command scanner
RPGIIB H, F, E, and L specification scanner
RPGIIC I and O specification scanner
RPGIID C specification scanner
RPGIIE Code and table generation phase
RPGIIF Listing generator
RPGIIG Assembly phase
RPGIIK Error dump phase
RPGIIP Parameter definition fil
RPGUNV Universal file used by many routines
SRTTAB Sort tables (primarily ERAFIL)
STINFL Set up input file
TRYNAM Interface to NAMTAB
XPAND Expand a table
XPNPPL Handle error traps
CHAPTER 2
COMPILER FILE STRUCTURE
The RPG II compiler uses three files specified by the user. These
files can be on any device which supports the type of data contained
in the file. The three files are:
1. SRC - The RPG II source program.
2. LST - The listing.
3. BIN - The relocatable binary produced by the compiler.
The compiler also uses several data files for temporary storage. All
of these files are stored on disk, and are deleted at the end of each
compilation. All files have the user's job number as the first three
characters of the filename, and the extension ".TMP". The three
characters that are appended to the job number to form the six
character filename are given below with a brief description of each
file:
1. ERA - Diagnostics to be output with the listing file.
2. GEN - Output of the syntax parsing phase.
3. CPY - A copy of the source with line numbers assigned.
4. CAL - A copy of the calculation specifications used to delay
calculation spec processing until after output processing.
5. AS1 - Intermediate language containing assembly information
for the data storage and table definition areas of the object
program.
6. AS2 - Intermediate language containing assembly information
for the detail calculation area of the object program.
7. AS3 - Intermediate language containing assembly information
for the total calculation and literal areas of the object
program.
COMPILER FILE STRUCTURE Page 2-2
2.1 CONTENTS OF SRC
SRC is the ASCII file containing the program to be compiled. It is
primarily manipulated by the routines contained in the "GETSRC"
module.
2.2 CONTENTS OF LST
The listing file is broken down into two subsections: A copy of the
source with line numbers assigned and error messages imbedded; and a
listing of the generated object output if the user has requested it
via the /A switch.
2.3 CONTENTS OF BIN
This file contains the relocatable binary data generated by the
compiler. This relocatable binary code is designed to be loaded with
LINK-10. A description of it's contents can be found in the LINK-10
Programmer's Reference Manual (DEC-10-ULKMA-B-D).
2.4 CONTENTS OF ERA
The diagnostic file contains a one-word entry for each error or
warning detected by the compiler. The file is written by Phases B, C,
D, and E, and read by Phase F. The entries are defined as follows:
Bit 0 Always zero to aid sorting of the file.
Bit 1 A zero if this diagnostic is to be imbedded in
the source listing, a one if the diagnostic is
to be listed seperately.
Bits 2-14 The line number of the line in error. This is
used to determine where in the listing the
error message should go.
Bit 21 A zero if this is a warning, a one if this is
a fatal error.
Bits 22-25 The compiler phase which generated the
diagnostic. (1=Phase A,...,5=Phase E).
Bits 26-35 A number identifying the error message. The
messages are defined in the module
"RPGERR.MAC".
COMPILER FILE STRUCTURE Page 2-3
2.5 CONTENTS OF GEN
The generator input file consists of operators and operands put out by
the parsing phases B, C and D. Each operator entry is two words, all
others are one word.
2.5.1 Operators
Word 1:
OP.OPR Bit 0 A zero to identify this as an operator
OP.OP Bits 1-8 A code for identifying the operator
Bits 9-15 Misc flags required for code generation
OP.LN Bits 16-28 Source line number to use if error found
Word 2:
OP.IND Bits 0-17 Link to conditioning indicator chain
OP.RES Bits 18-35 Resulting indicator chain link
2.5.2 Operands, Other Than Literals
Word 1:
OP.OPR Bit 0 A one to identify this as an operand
OP.LIT Bit 1 A zero to identify this as other than a
literal
OP.AC Bit 2 Operand is TEMP of AC's
OP.LNK Bits 18-35 Table link to operand
2.5.3 Operands, Literal
Word 1:
OP.OPR Bit 0 A one to identify this as an operand
OP.LIT Bit 1 A one to identify this as a literal
OP.NUM Bit 2 A one to identify this as a numeric literal, a
zero to identify this as non-numeric
OP.FIG Bit 3 A one if a figurative constant
OP.LNK Bits 18-35 Table link to literal (if OP.FIG = 0)
2.6 CONTENTS OF CPY
This file contains a copy of the source file with line numbers
assigned and some editing done. There is a one word entry for each
line which contains:
COMPILER FILE STRUCTURE Page 2-4
Bits 0-6 The printer control character for the
preceding line (form-feed or line-feed)
Bit 7 Always zero
Bits 8-20 The assigned line number for this line
Bits 21-24 The first two characters of the source line
Bit 35 Always one to identify this as a header word
The remaining words for each line contain the ASCII characters copied
from the source file.
2.7 CONTENTS OF CAL
This file contains a copy of the calculation specifications copied
from the source file. This copy is used to delay processing of the
calculation statements until after the output statements have been
processed. The file is just an ASCII copy from the source, with no
editing done.
2.8 CONTENTS OF AS1, AS2, AS3
The output of Phase E is a set of files containing directions for the
assembly phase. Each entry in the file consists of a header word
followed by one or more words of more definitive data.
2.8.1 Addresses
The header data words may contain an address. That address has a type
code in its first three bits, followed by an address relative to some
table. The type codes are:
AS.CNS 0 The remainder of the address is a constant
AS.ICH 1 The address is relative to the start of ICHTAB
AS.PRO 2 The address is relative to PROTAB
AS.EXT 3 The address is relative to EXTAB
AS.FTB 4 The address is relative to FTBTAB
AS.OCH 5 The address is relative to OCHTAB
AS.CNB 6 The increment (see 2.8.2) is a constant
AS.MSC 7 Miscellaneous (see 2.8.2)
2.8.2 Address Increment
Occasionally the address must be modified by some increment. The
increment has a type code in its first three bits, followed by a
constant amount to increment by.
COMPILER FILE STRUCTURE Page 2-5
The values for the type codes are:
AS.ABS 0 Add constant to the address
AS.OTB 1 Add constant to OTFBAS
AS.OCB 2 Add constant to OCHBAS
AS.LIT 3 Add constant to base of the literal pool
AS.ICB 4 Add constant to ICHBAS
AS.DOT 5 Add constant to current location
AS.TMP 6 Add constant to base of runtime impure area
AS.DAT 7 Add constant to base of data storage area
2.8.3 Instruction
Word 1:
Bit 0 Always zero to identify this as an instruction
Bit 1 If there is an increment word following this,
this bit is a one
Bits 2-8 Operation code (see 2.8.8)
Bits 9-12 Accumulator field for the instruction
Bit 13 Indirect bit for instruction
Bits 14-17 Index field for the instruction
Bits 18-35 The address (see 2.8.1)
Word 2:
This word exists only if bit 1 of word 1 was a one. It has
zero in the left half, and an increment (see 2.8.2) in the
right half.
2.8.4 Byte Pointer
Word 1:
Bits 0-2 Always 4
Bits 3-17 Not used
Bits 18-35 Address (see 2.8.1)
Word 2:
Bits 0-17 The left half of the byte pointer, as
generated by the MACRO-10 psuedo-op.
Bits 18-35 Increment (see 2.8.2)
COMPILER FILE STRUCTURE Page 2-6
2.8.5 XWD
Word 1:
Bits 0-2 Always 5
Bits 3-17 Not used
Bits 18-35 Number of following two word entries
The header word is followed by one or more two word entries as
follows:
First Word:
Bits 0-17 Address increment for left half of the XWD
Bits 18-35 Address for the left half of the XWD
Second Word:
Bits 0-17 Address increment for right half of the XWD
Bits 18-35 Address for the right half of the XWD
2.8.6 Constant
Word 1:
Bits 0-2 Always 6
Bit 3 ASCII constant
Bit 4 SIXBIT constant
Bit 5 One-word decimal constant
Bit 6 Two-word decimal constant
Bit 7 Floating point constant
Bit 8 Octal constant
Bits 9-12 Not used
Bits 13-17 Number of characters in the floating point
mantissa
Bits 18-35 Number of words containing the constant
Following the header word is the value constant, in as many words as
is necessary. Floating point constants are two words apiece: the
first word is the tens exponent in binary; the second word is the
mantissa, four bits per digit.
2.8.7 Micellaneous
Word 1:
Bits 0-2 Always 7
Bit 3 Paragraph or section name (for listing
pruposes)
Bit 4 Special tag (for listing purposes)
Bit 5 RELOC psuedo-op
COMPILER FILE STRUCTURE Page 2-7
Bits 6-16 Not used
Bit 17 Increment word follows
Word 2: Present only if bit 17 of word 1 is a 1
Bits 0-17 Not used
Bits 18-35 Address increment (see 2.8.2)
2.8.8 Instruction Codes
A complete list of the instruction codes and their compiler symbols
can be found in the module "GENCOM.MAC".
CHAPTER 3
COMPILER INTERNAL TABLE STRUCTURE
The RPGII compiler makes use of a great many internal tables during
the compilation process. This chapter is intended to be a description
of those tables. A complete, and up to date, listing of the tables
and their entries may be found in the module PURE.MAC.
3.1 FILTAB - THE FILE TABLE
FILTAB consist of one 8 word entry for each file used by the object
program. These entries are arranged as follows:
Word 1:
Bits 0-2 Always 0 to identify table.
FI.NAM Bits 3-17 Relative pointer to NAMTAB entry for this
file.
FI.TYP Bits 18-20 File Type as follows:
000 = Input
001 = Output
010 = Update
011 = Combined
100 = Display
FI.DES Bits 21-23 File Designation:
000 = Primary
001 = Secondary
010 = Chained
011 = Record Address
100 = Table or Array
101 = Demand
110 = Blank (Output or Display)
FI.PRO Bits 24-26 Processing Mode:
000 = Consecutive
001 = By ADDRout
010 = Sequential by key
011 = Sequential within limits (not supported)
100 = Random by relative record
101 = Random by Record Key
FI.ORG Bits 27-28 File Organization:
00 = One I/O area (sequential or direct)
COMPILER INTERNAL TABLE STRUCTURE Page 3-2
10 = Indexed file
11 = ADDRout file (if not and FI.DES = 011, is limits
file)
FI.RAF Bits 29-30 Record Address Format
00 = Unpacked
01 = Binary (not supported)
10 = Packed (not supported)
11 = None
FI.DEV Bits 31-34 Device Name:
.FIMF1 0 = MFCU input hopper 1
.FIMF2 1 = MFCU input hopper 2
.FICDR 2 = READ01 (CDR:)
.FILPT 3 = PRINTER (LPT:)
.FILP2 4 = PRINTR2 (obsolete)
.FITTY 5 = CONSOLE (TTY:)
.FIDSK 6 = DISK (DSK:)
.FIMTA 7 = TAPEn (MTAn:)
FI.EOF Bit 35 Program may end only after all records from
this file have been processed when this bit is
set.
Word 2:
FI.KYP Bits 0-11 Relative key position within record
FI.BKL Bits 12-23 Block length
FI.RCL Bits 24-35 Record length
Word 3:
FI.SEQ Bits 0-1 Sequence checking option:
00 = No checking
01 = Ascending order
10 = Descending oreder
FI.BUF Bits 2-8 Tape buffer offset
FI.AST Bit 9 ASCII File flag
FI.REW Bits 10-11 Tape rewind option:
00 = Rewind at EOF
01 = Unload at EOF
10 = Leave tape at EOF
FI.EXT Bits 12-17 Number of extents
FI.ADD Bits 18-19 File addition option:
00 = No additions
01 = Ordered additions
10 = Unordered additions
FI.OVI Bits 20-27 Overflow indicator
FI.ADF Bit 28 Record Address link flag
FI.LPP Bits 29-35 Lines per Page
Word 4:
FI.OVL Bits 0-5 Overflow line
FI.UNT Bits 6-9 Unit number for TAPE
FI.KYL Bits 12-16 Length of key field
FI.EXI Bits 17-24 External Indicator
COMPILER INTERNAL TABLE STRUCTURE Page 3-3
Word 5:
FI.COR Bits 0-17 Core index size (not implemented)
FI.ADL Bits 18-35 Link to ADDRout or Limits file
Word 6:
FI.DAT Bits 0-17 Link to primary DATAB item
FI.LIN Bits 18-29 Line number of defining file specification
Word 7:
FI.PHY Bits 0-35 Physical (SIXBIT) name of file
Word 8:
FI.OTF Bits 0-17 Link to corresponding OTFTAB item
3.2 DATAB - THE DATA ITEM TABLE
DATAB, the data item table, consists of a series of 13 word entries
linked together in such a manner as to represent the input and output
data structures defined in the user's program. It also contains
descriptions of data items defined in the calculation specifications
and not used in either the input or output sections.
For each input or output file there is a corresponding FILTAB entry as
defined above. This entry contains a pointer (FI.DAT) to the first
DATAB item in the input or output chain. This first item contains the
data defining the first record. If there are additional input or
output records they are linked together via the DA.MAJ pointer. Each
record also contains a pointer to those data items contained within
the record. These data items are chained together via the DA.BRO
link.
Another linkage of importance is the same name (DA.SNM) linkage. Via
this pointer all items that have a common name are linked together.
This link is useful for compiling composite information on a field.
The remainder of the DATAB items are defined as follows:
Word 1:
Bits 0-2 Always 01 to identify the table
DA.NAM Bits 3-17 NAMTAB link
DA.MAJ Bits 18-35 Link to next major (record) item
Word 2:
DA.BRO Bits 0-17 Link to next minor (field) item
DA.IND Bits 18-35 Link to conditioning indicators
COMPILER INTERNAL TABLE STRUCTURE Page 3-4
Word 3:
DA.VAL Bits 0-17 Link to literal value of field
DA.COR Bits 18-35 Pointer to assigned core location
Word 4:
DA.NPS Bits 0-1 Number of entries per sequence type:
00 = Sequence not checked
01 = 1 record/type
10 = n records/type
DA.RTR Bit 2 Record type is required
DA.TRA Bit 3 Trailer item (not supported)
DA.LHI Bit 4 Look-ahead item
DA.STS Bits 5-7 MFCU stacker select
DA.FLD Bits 8-9 Field type:
00 = Alphanumeric
01 = Packed decimal (not supported)
10 = Packed binary (not supported)
11 = Unpacked numeric
DA.SIZ Bits 10-21 Size of field
DA.DEC Bits 22-25 Number of decimal positions
DA.PRI Bit 26 Print and punch MFCU (not supported)
DA.PRO Bit 27 Punch only MFCU (not supported)
DA.STR Bit 28 Sterling sign (not supported)
0 = not used
1 = postion stored in DA.STP
DA.RES Bits 29-34 Byte residue for core pointer (DA.COR)
DA.IMD Bit 35 Array index is immediate
Word 5:
DA.RII Bits 0-7 Record identifying indicator
DA.CLI Bits 8-15 Control level indicator
DA.FPL Bits 16-23 Positive field indicator
DA.STP Bits 24-35 Sterling position (not supported)
Word 6:
DA.ORT Bits 0-1 Output record type:
00 = Heading
01 = Detail
10 = Total
11 = Exception
DA.ARC Bit 2 Add record
DA.FOV Bit 3 Fetch overflow
DA.SPA Bits 4-5 Space after count
DA.SKA Bits 6-12 Skip after line number
DA.EDT Bits 13-16 Edit Code:
1 = "1" 11 = "J"
2 = "2" 12 = "K"
3 = "3" 13 = "L"
4 = "4" 14 = "M"
5 = "A" 15 = "X"
6 = "B" 16 = "Y"
COMPILER INTERNAL TABLE STRUCTURE Page 3-5
7 = "C" 17 = "Z"
10 = "D"
DA.BLA Bit 17 Blank field after printing
DA.SPB Bits 18-19 Space before count
DA.END Bits 20-31 Field end position in output record
DA.LDC Bit 32 Table/array loads at compile time
DA.LDR Bit 33 Table/array loads at pre-execution time
DA.LDE Bit 34 Table/array loads at execution time
DA.DMP Bit 35 Table/array dumps at end of job
Word 7:
DA.OCC Bits 0-14 Number of occurs (Max index) of table/array
DA.ALT Bit 15 Alternate table
DA.INF Bit 16 Input section flag (this item seen in input
section)
DA.RND Bit 17 Round (Half-adjust) the result
DA.ALL Bits 18-35 Table link to alternate table
Word 8:
DA.EPR Bits 0-9 Number of entries per record
DA.SEQ Bits 10-11 Sequence checking:
00 = No check
01 = Ascending sequence
10 = Descending sequence
DA.ARE Bit 12 This item an array entry
DA.ADD Bit 13 Add record
DA.FMT Bits 14-17 Field data format:
0 = SIXBIT
1 = ASCII
2 = EBCDIC
DA.LDP Bits 18-35 Table link to file this table/array loads from
Word 9:
DA.DPP Bits 0-17 Table link to file this table/array dumps to
DA.SNM Bits 18-35 Table to link to item with same name
Word 10:
DA.FRP Bits 0-11 From relative field location
DA.TOP Bits 12-23 To relative field location
DA.MAT Bits 24-31 Matching indicator
DA.TAB Bit 32 Table flag (valid for OCHTAB linked items
only)
Word 11:
DA.FMN Bits 0-7 Negative field indicator
DA.FBZ Bits 8-15 Blank or zero field indicator
DA.SKB Bits 16-22 Skip before line number
DA.FRR Bits 23-30 Field record relation indicator
DA.DUN Bit 31 This item processed by Phase E
DA.NDF Bit 32 This item not fully defined (used?)
DA.FLS Bit 33 This item defined in file section
COMPILER INTERNAL TABLE STRUCTURE Page 3-6
Word 12:
DA.ICH Bits 0-17 Pointer to related ICHTAB item
DA.ARP Bits 18-35 Pointer to array this item references
Word 13:
DA.INP Bits 0-17 Pointer to index (or index itself if DA.IMD =
1)
DA.LIN Bits 18-30 Line number of defining line (for errors)
DA.LTF Bit 31 Literal flag
DA.RSV Bits 32-35 Reserved word flag/code (set up by Phase E):
1 = UDATE 5 = PAGE
2 = UDAY 6 = PAGE1
3 = UMON 7 = PAGE2
4 = UYEAR
3.3 IDTTAB - THE INDICATOR TABLE
The indicator table consists of a series of 1 word entries linked
together form an equivalent of the indicator checks used in the user's
program. Rather than actually being linked, consecutive entries are
used until the ID.END flag is seen, indicating the end of the chain.
In addition to using IDTTAB to link together indicator checks for
output records and calculations, it is also used to link together
checks for record identifying indicators in the input specs. When
used for this, only OR lines contain an indicator, which is placed in
ID.RII rather than in the usual ID.IND. Placed in ID.IND instead, is
the character that is to be looked for in column ID.POS of the input
record.
The assigned sequence number, ID.SEQ, is also only used in input
chains. This number corresponds to the record sequence number given
on the input specs.
The IDTTAB items are defined as follows:
Word 1:
ID.OR Bit 0 0 = Boolean AND relation with previous entry,
1 = Boolean OR relation.
ID.NOT Bit 1 Boolean NOT condition applied to ID.OR
ID.IND Bits 2-9 Indicator/character
ID.POS Bits 10-21 Character position
ID.END Bit 22 This is last entry in this chain
ID.RII Bits 23-30 Record identifying indicator (OR line only)
ID.SEQ Bits 31-35 Assigned sequence number (first entry only)
COMPILER INTERNAL TABLE STRUCTURE Page 3-7
3.4 PROTAB - THE TAG NAME TABLE
The tag name table consists of 2 word entries used to store
information about symbols used in TAG and BEGSR statements. The
entries are defined as follows:
Word 1:
PR.ID Bits 0-2 Always 4 to identify the table
PR.NAM Bits 3-17 NAMTAB pointer to value of symbol
PR.LNK Bits 18-35 Pointer to assigned location of tag
Word 2:
PR.SEG Bit 0 Segment containing the tag, as follows:
0 = AS2FIL
1 = AS3FIL
PR.BSR Bit 1 Tag used in a BEGSR flag
3.5 LITAB - THE LITERAL TABLE
LITAB contains information about literals generated by the code
generation phase of RPG II. This information is dumped into AS3FIL at
the end of that phase. Each LITAB entry consists of a header word
followed by words containing the literal value. The header word is
defined as follows:
In the left half:
1 XWDLIT An XWD
2 BYTLIT A byte pointer
3 ASCLIT ASCII text
4 SIXLIT SIXBIT text
5 D1LIT 1-word decimal
6 D2LIT 2-word decimal
7 FLTLIT Floating point
10 OCTLIT Octal
In the right half:
Number or following words containing data.
The data words are described in Section 2.8 of this manual.
COMPILER INTERNAL TABLE STRUCTURE Page 3-8
3.6 VALTAB - THE VALUE TABLE
VALTAB holds the literals found in the output specifications as edit
words or output literals. Each value is placed in one or more words.
The first word has the number of characters in bits 0-6; the
remainder of that word, and the following words, if any, contain an
ASCII string.
3.7 NAMTAB - THE NAME TABLE
NAMTAB contains the names of all files and data items found in the
source program. This is a table driven by several hash tables. The
search technique is described in the module "TRYNAM.MAC". Each NAMTAB
entry consists of at least two words, defined as below:
Word 1:
Bits 0-35 Undefined (available for flags)
Word 2: The name, in SIXBIT, over as many words as is
necessary. The name is terminated by a zero
byte.
3.8 EXTAB - THE EXTERNAL NAME TABLE
EXTAB contains information about external routines. This table is
used only by the EXIT operation at the present time, but is included
in this form to allow for the possibility of reentrant code
generation. Each two word entry in defined as follows:
Word 1:
Bits 0-2 Always 5 to identify the table
EX.NAM Bits 3-17 Pointer to NAMTAB entry for this name
Word 2:
EX.NRS Bit 0 Name is used by non-resident segment
EX.USN Bit 1 Use flag:
0 = OPsys name
1 = User name
EX.PID Bit 2 This is the program ID
EX.ENT Bit 3 This is an entry point
EX.CAL Bit 4 Referenced by a CALL
EX.CNT Bits 15-17 Count of extra words allocated
EX.HLD Bits 18-35 Misc. uses
CHAPTER 4
RUNTIME SYSTEM OVERVIEW
4.1 COMPONENTS OF RPGLIB
The RPG II runtime system, RPGLIB, is a collection of library routines
to perform various functions needed by the object program. In
addition it contains a interpretive module, RPGMAN, which simulates
the RPG II cycle, taking the burden of the code generators in the
compiler. The routines contained in RPGLIB are listed below:
CBLIO Low level I/O routines (taken from LIBOL)
CHREQV Generates a universal file containing the
character equivalences across the supported
character sets
CDD Convert from one display format to another
COMP Comparison routines
COMUNI Define the impure area
DEBUG Debugging routines
DIV11 Divide single precision by single precision
DPADD Do double precision add
DPDIV Do double precision divide
DPMUL Do double precision multiplication
DPSUB Do double precision subtraction
DSPLY Handle the DSPLY operation
EASTBL Define EBCDIC, ASCII, SIXBIT conversion tables
EDIT Handle editing
FLGDF Define flags for LIBOL compatibility
FTDEFS Define file table constants for CBLIO
GC Convert COMP-3 to binary
GD Convert display to binary
INTERM Define default switches
MAGNEG Take magnitude and negative of numbers
MOVE Perform moves
MOVSGN Move sign field
NUMEQV Define character/number equivalences
PC Convert binary to COMP-3
PD Convert binary ti display
RPGASM Define user selected switches
RPGIO Perform high level I/O
RPGIMP Define impure area
RPGMAN Simulate RPG II cycle
RPGPUR Define pure area
RUNTIME SYSTEM OVERVIEW Page 4-2
RPGPRM Define miscellaneous parameters
RPGSWI Define switch macros and constants
SETRET Do return and exit setup
SPAC Check for spaces
SQRT Find a square root
SUBSCR Do array/table subscripting
UUOHAN Handle UUO traps
4.2 INPUT/OUPUT IN RPGLIB
I/O in the runtime system is performed by two modules: RPGIO and
CBLIO. Each performs a different level of I/O.
4.2.1 RPGIO
This module contains the high level I/O routines. It contains the
routines that the generated code talks to, and also the routines that
the RPG II cycle simulator RPGMAN talks to. It is within this module
that all indicator checking and buffer setup is done.
4.2.2 CBLIO
All actual I/O is done within this module. This is the same module
contained in COBOL's runtime system LIBOL. This module was used to
maintain complete compatibility with COBOL's I/O system, especially
the ISAM handlers, without introducing still another piece of software
that must be supported.
CHAPTER 5
RUNTIME SYSTEM INTERNAL TABLE STRUCTURE
The primary tables that the runtime system utilizes are: OTFTAB,
FTBTAB, DEVTAB, ICHTAB, OCHTAB, ARRTAB, and CHNTAB. All except CHNTAB
are set up by the compiler and output as part of the object program.
CHNTAB is allocated and set up by RPGLIB. IDTTAB is also used by the
runtime system, but each entry is assigned a unique location in the
literal pool. Thus, although the entries are formated that same as in
the compiler, the table itself is distributed throughout memory,
rather than grouped in one place as with the other tables.
5.1 CHNTAB - THE CHANNEL TABLE
CHNTAB consists of one 23 word table for each file. Its primary use
is to allow quick access to some of the information contained in
OTFTAB and FTBTAB. When a file is opened, it is assigned a
pseudo-channel number. This psuedo-channel number is the entry number
within CHNTAB. The offsets into CHNTAB are defined as follows:
0 CHN I/O channel assignment
1 BLK Blocking Factor (obsolete)
2 CUR Current block in buffer (not always correct)
3 PNT SIXBIT byte pointer
4 KEY Relative key for next file access
5 RWF REWRITE flag
6 BSZ Buffer size in words
7 BUF Base of I/O buffer
10 BCN Byte count in current buffer (obsolete)
11 EOF This file has reached end-of-file
12-16 UPD Update key
17 LIN Line counter
20 IPC Input chain pointer
21 SEQ Sequence number
22 RII Record identifying indicator
Those entries marked as obsolete are defined for historical reasons
only.
RUNTIME SYSTEM INTERNAL TABLE STRUCTURE Page 5-2
5.2 OTFTAB - THE OBJECT TIME FILE TABLE
OTFTAB contains much the same information as FILTAB but has been
rearranged and condensed to be of more use to the runtime system.
While this table is built at compile time, it is used only at runtime
by the runtime system. Each file used by the object program generates
one 9 word OTFTAB entry.
Within this entry are pointers to the input and output chains related
to the file. These pointers point into ICHTAB and OCHTAB,
respectivly. Also contained in this entry is a pointer to the
corresponding FTBTAB entry so that the runtime system can gain access
to CBLIO generated information.
The entries are defined as follows:
Word 1:
OT.COR Bits 0-17 Pointer to core index (not supported)
OT.ADP Bits 18-35 Pointer to ADDRout file
Word 2:
OT.BFP Bits 0-17 Pointer to record buffer
OT.OPC Bits 18-35 Pointer to OCHTAB output chain
Word 3:
OT.IPC Bits 0-17 Pointer to ICHTAB input chain
Word 4:
OT.NAM Bits 0-35 Physical SIXBIT name of file
Word 5:
OT.TYP Bits 0-2 File type (as defined in FI.TYP)
OT.DES Bits 3-5 File description (as defined in FI.DES)
OT.PRO Bits 6-8 Processing mode (as defined in FI.PRO)
OT.ORG Bits 9-10 File organization (as defined in FI.ORG)
OT.RAF Bits 11-12 Record address format (as defined in FI.RAF)
OT.DEV Bits 13-16 File device (as defined in FI.DEV)
OT.EOF Bit 17 EOF option (as defined in FI.EOF)
OT.BLK Bits 18-35 Blocking factor
Word 6:
OT.KYP Bits 0-11 Key position within record
OT.SEQ Bits 12-13 Sequence checking (as defined in FI.SEQ)
OT.BUF Bits 14-19 Tape buffer offset
OT.AST Bits 20 ASCII file option
OT.REW Bits 21-22 Tape rewind option (as defined in FI.REW)
OT.EXT Bits 23-28 Number of extents
OT.ADD Bits 29-30 File addition option (as defined in FI.ADD)
OT.KYL Bits 31-35 Length of key field
RUNTIME SYSTEM INTERNAL TABLE STRUCTURE Page 5-3
Word 7:
OT.OVI Bits 0-7 Overflow indicator
OT.EXI Bits 8-15 External conditioning indicator
OT.OVL Bits 16-21 Overflow line
OT.CHN Bits 32-35 Psuedo-channel number assigned to file
Word 8:
OT.CRS Bits 0-17 Core index size (not supported)
OT.BSZ Bits 18-35 Buffer size in words
Word 9:
OT.BSC Bits 0-17 Buffer size in characters
OT.LAS Bit 18 "I am the last OTFTAB entry" flag
OT.LPP Bits 19-25 Lines per page
5.3 FTBTAB - THE CBLIO FILE TABLE
FTBTAB is generated to be compatible with the CBLIO module, which does
all of the actual I/O for the runtime system. A bare minimum of
explanation is given here, as little trouble should ever be
experienced with this table. It should be kept in mind that all items
defined below are used by RPG II but are defined only for CBLIO
compatibility. More complete documentation may be found in CBLIO.MAC.
In addition to the 32 word entry defined below, there is also a 32
word DEVTAB preceding each FTBTAB entry. This DEVTAB area is used
only by CBLIO, thus the compiler merely outputs zeroes for this area.
Documentation on the contents of DEVTAB can also be found in
CBLIO.MAC.
Words 1-5:
FT.FNM The filename used within the users program in
SIXBIT. This is not the physical filename
that a LOOKUP is done on, but rather the
descriptive filename given by the user. Used
for error messages.
Word 6:
FT.CVR Bits 0-5 Compiler version number
FT.BLC Bit 6 Buffer location is assigned
FT.SDF Bit 7 SORT descriptor flag
FT.NOD Bits 8-17 Number of devices
FT.DNM Bits 18-35 Pointer to first device name
Word 7:
FT.NFL Bits 0-4 Number of file limits
FT.PMT Bits 5-17 File position on Mag-tape
RUNTIME SYSTEM INTERNAL TABLE STRUCTURE Page 5-4
FT.NFT Bits 18-35 Pointer to next file table
Word 8:
FT.NAB Bits 0-4 Number of alternate buffers
FT.MRS Bits 5-17 Maximum record size
FT.RRC Bits 18-35 Records between RERUN dump
Word 9:
FT.VLR Bit 0 Variable length EBCDIC records
FT.NSL Bit 2 Non-standard labels
FT.STL Bit 3 Standard labels
FT.IOF Bit 6 Input/output file
FT.DDM Bits 7-9 Device data mode:
0 = SIXBIT 3 = EBCDIC
1 = Binary 4 = ASCII-8
2 = ASCII 5-7 = Unused
FT.RRE Bit 10 RERUN dump at end-of-reel
FT.RCR Bit 11 RERUN on record count
FT.OPT Bit 13 File is optional
FT.CDM Bits 14-15 Core data mode:
0 = SIXBIT
1 = Binary
2 = ASCII
3 = EBCDIC
FT.MOD Bits 16-17 File I/O mode:
0 = Sequential
1 = Random
2 = ISAM
3 = Unused
FT.REC Bits 18-35 Address of record area
Word 10:
FT.NLS Bits 0-17 Non-standard label size
FT.FSD Bits 18-35 Link to file that shares same device
Word 11:
FT.BKF Bits 6-17 Blocking factor
FT.ACK Bits 18-35 Address of actual key table
Word 12:
FT.VID Bits 0-35 Byte pointer to value-of-id
Word 13:
FT.VDW Bits 0-35 Byte pointer to value-of-date-written
Word 14:
FT.SBA Bits 0-17 Link to file that shares the same buffer area
FT.EUP Bits 18-35 Address of error-use procedure
RUNTIME SYSTEM INTERNAL TABLE STRUCTURE Page 5-5
Word 15:
FT.BBR Bits 0-17 Address of before-beginning-reel procedure
FT.BBF Bits 18-35 Address of before-beginning-file procedure
Word 16:
FT.ABR Bits 0-17 Address of after-beginning-reel procedure
FT.ABF Bits 18-35 Address of after-beginning-file procedure
Word 17:
FT.BER Bits 0-17 Address of before-ending-reel procedure
FT.BEF Bits 18-35 Address of before-ending-file procedure
Word 18:
FT.AER Bits 0-17 Address of after-ending-reel procedure
FT.AEF Bits 18-35 Address of after-ending-file procedure
Word 19:
FT.DNS Bits 0-2 Mag-tape density:
0 = System standard
1 = 200 BPI
2 = 556 BPI
3 = 800 BPI
4 = 1600 BPI
FT.PAR Bit 4 Mag-tape parity:
0 = Odd
1 = Even
FT.OUP Bit 5 Open use-procedure when enter fails
FT.PPN Bits 18-35 Pointer to PPN
Word 20:
FT.BSK Bits 0-35 Byte pointer to symbolic key
Word 21:
FT.BRK Bits 0-35 Byte pointer to record key
Word 22:
FT.KTY Bits 15-17 ISAM key type:
0 = Non-numeric
1 = Numeric display < 11 digits
2 = Numeric display > 10 digits
3 = COMP < 11 digits
4 = COMP > 10 digits
5 = COMP-1
FT.KSG Bit 20 ISAM key is signed
FT.KLB Bits 24-35 ISAM key length in bytes
Word 23:
RUNTIME SYSTEM INTERNAL TABLE STRUCTURE Page 5-6
FT.OWA Bits 0-8 ISAM owner write access. Rightmost 4 bits
correspond to Read, Rewrite, Write and Delete
privledges.
FT.OTA Bits 9-17 ISAM other write access. Same bit assignments
as FT.OWA.
FT.RTC Bits 18-35 ISAM retained record count
Word 24:
FT.PFS Bits 0-35 Byte pointer to file-status
Word 25:
FT.PEN Bits 0-35 Byte pointer to error-number
Word 26:
FT.PAC Bits 0-35 Byte pointer to action-code
Word 28:
FT.PID Bits 0-35 Byte pointer to value-of-id
Word 28:
FT.PBN Bits 0-35 Byte pointer to block-number
Word 29:
FT.PRN Bits 0-35 Byte pointer to record-number
Word 30:
FT.PFN Bits 0-35 Byte pointer to file-name
Word 31:
FT.PFT Bits 0-35 Byte pointer to file-table
Word 32:
FT.LHL Bits 0-35 Pointer to low,,high file limit
5.4 ICHTAB - THE INPUT CHAIN TABLE
ICHTAB contains entries chained together much as the DATAB items were;
the chaining path defines a data structure representing the users
input specifications. Each of the 7 word entries contains 2 pointers
of interest; the first is IC.NXR which points to the next record
level item in the chain; the second is IC.NXF which points to the
next field level item in the chain. In both cases, a pointer of zero
terminates the chain.
RUNTIME SYSTEM INTERNAL TABLE STRUCTURE Page 5-7
The remainder of the entries are defined below:
Word 1:
IC.DES Bits 0-35 Byte pointer to assigned core location
Word 2:
IC.RII Bits 0-17 Pointer to IDTTAB record identifying indicator
chain
IC.NXF Bits 18-35 Pointer to next field level item
Word 3:
IC.NXR Bits 0-17 Pointer to next record level item
IC.ARP Bits 18-35 Pointer to array this item references
Word 4:
IC.INP Bits 0-17 Pointer to array index (or array index itself
if IC.IMD = 1
Word 5:
IC.FMN Bits 0-7 Minus field indicator
IC.FBZ Bits 8-15 Blank/zero field indicator
IC.FPL Bits 16-23 Plus field indicator
IC.CLI Bits 24-31 Control level indicator
IC.NPS Bits 32-33 Number per sequence (same as DA.NPS)
IC.FLD Bits 34-35 Field type (same as DA.FLD)
Word 6:
IC.FRR Bits 0-7 Field record relation indicator
IC.MAT Bits 8-15 Matching indicator
IC.RTR Bit 16 Record type required
IC.LHI Bit 17 Look ahead item
IC.STS Bits 18-20 MFCU stacker select
IC.SIZ Bits 21-32 Size of field
IC.SEQ Bits 33-34 Sequence check option (same as DA.SEQ)
IC.IMD Bit 35 Immediate array reference
Word 7:
IC.SRC Bits 0-11 Character position in source
IC.OCC Bits 12-26 Number of occurs for array item
IC.FMT Bits 27-31 Data format (same as DA.FMT)
RUNTIME SYSTEM INTERNAL TABLE STRUCTURE Page 5-8
5.5 OCHTAB - THE OUTPUT CHAIN TABLE
OCHTAB is the direct counterpart of ICHTAB, but for the output
specifications. OCHTAB is linked in the same manner as ICHTAB, but
each 7 word entry contains information pertaining to output records
and fields. Each entry is defined as follows:
Word 1:
OC.IDX Bits 0-17 Pointer to array index
OC.NXR Bits 18-35 Pointer to next record level item in chain
Word 2:
OC.NXF Bits 0-17 Pointer to next field level item in chain
OC.IND Bits 18-35 Pointer to conditioning IDTTAB chain
Word 3:
OC.SRC Bits 0-35 Pointer to data source
Word 4:
OC.FLD Bits 0-1 Field type (same as DA.FLD)
OC.SIZ Bits 2-13 Size of field
OC.DEC Bits 14-17 Number of decimal positions in field
OC.STP Bits 18-29 Sterling position (not supported)
OC.PRI Bit 30 MFCU print & punch (not supported)
OC.PRO Bit 31 MFCU print only (not supported)
OC.STR Bit 32 Sterling sign (not supported)
OC.ORT Bits 33-34 Output record type (same as DA.ORT)
OC.ADD Bit 35 Add a record
Word 5:
OC.FOV Bit 0 Forced overflow
OC.SKB Bits 1-7 Skip before line number
OC.SKA Bits 8-14 Skip after line number
OC.SPB Bits 15-16 Space before count
OC.SPA Bits 17-18 Space after count
OC.END Bits 19-30 Field end position in output record
OC.STS Bits 31-34 MFCU stacker select
OC.IMD Bit 35 Array index is immediate
Word 6:
OC.OCC Bits 0-14 Number of occurs of array/table
OC.EDT Bits 15-18 Edit code (same as DA.EDT)
OC.LTF Bit 19 Literal only output flag
OC.LSZ Bits 20-28 Size of literal
OC.RSV Bits 29-32 Reserved word code (same as DA.RSV)
OC.BLA Bit 33 Blank this field after printing
OC.TAB Bit 34 "This is a table" flag
Word 7:
RUNTIME SYSTEM INTERNAL TABLE STRUCTURE Page 5-9
OC.ARP Bits 0-17 Pointer to array this item references
OC.EDP Bits 18-35 Pointer to edit word/literal
5.6 ARRTAB - THE ARRAY LOAD/DUMP TABLE
ARRTAB is generated for use by the runtime system whenever a table or
array must be loaded or dumped by the runtime system. This table
consists of a series of 4 word entries each defining a table that is
to loaded or dumped. The entries are set up as follows:
Word 1:
AR.PNT Bits 0-35 Byte pointer to array/table
Word 2:
AR.SIZ Bits 0-9 Size of array entry
AR.OCC Bits 10-19 Number of occurs of the array/table
AR.EPR Bits 20-29 Number of entries per record
AR.LDM Bit 30 Dump/Load flag:
0 = Load
1 = Dump
AR.LAs Bit 31 "This is the last entry" flag
Word 3:
AR.FIL Bits 0-17 Link to OTFTAB entry for file this loads/dumps
from/to
AR.ASZ Bits 18-27 Size of alternating table/array (if any)
Word 4:
AR.ALT Bits 0-35 Byte pointer to Alternate table/array (if any)
APPENDIX A
REFERENCE TABLES
A.1 INDICATOR VALUES
In both the compiler and the runtime system, all indicators are
referenced by the numbers described below:
Indicator Octal Value
01-99 1-143
H1-H9 144-154
L1-L9 155-165
LR 166
OA-OG 167-175
OV 176
M1-M9 177-207
MR 210
L0 211
1P 212
U1-U8 213-222