MIDAS and STINK version of REL file format

[larsbrinkhoff]

The REL file format as used by MIDAS and STINK is not documented. Presumably it could be reverse engineered by looking inside MIDAS and STINK, but it's not very ovbious where to look.

[larsbrinkhoff]

I took a look at SAIL; JOBDAT REL:

It begins with

002002,,000000

Next comes a symbol table. Every symbol is described by five words. Here's an example:

457573,,601127  ;Symbol name in SQUOZE: "JOBSVM"
000000,,000075  ;Symbol value
314201,,176553
004003,,000000
000000,,000000

The first symbol seems to be the symbol table block name or file name.

The table is terminated by a symbol entry that starts with 0. After that comes four words. The first looks like two negative half words. The third is the block name or file name again.

[larsbrinkhoff]

Assembling a simple file titled BARFOO which just defines FOOBAR=1234567.

FAIL produces this REL file:

OCTAL         SQUOZE
002004000000  1O9QJV   ;Type 10, local sybols
051301670001  BARFOO
000000000001       0
014544243324  FOOBAR
000001234567    4C%U
707725407662  9D%33H   ;Checksum
000602000000   %K18N   ;Type 3, code
000000000000        
000000000000        
777176777777   $6VBU   ;Checksum
001001000000  0BK8ZV   ;Type 4, program name
051301670001  BARFOO
725476107776  RCI6%$   ;Checksum

MIDAS produces this REL file:

OCTAL         SQUOZE
000600000000   %BXLF   ;Type 3, code
777200777777   $E%%%   ;Checksum
000600000000   %BXLF   ;Type 3, code
777200777777   $E%%%   ;Checksum
000600000000   %BXLF   ;Type 3, code
777200777777   $E%%%   ;Checksum
000202000001   CBI70   ;Type 1, loader command
000000000000        
000000000000        
777576777776  0NFEDD   ;Checksum
002004000000  1O9QJV   ;Type 10, local sybols
051301670001  BARFOO
000000000000        
014544243324  FOOBAR
000001234567    4C%U
707725407663  9D%33I   ;Checksum
001001000000  0BK8ZV   ;Type 4, program name
051301670001  BARFOO
725476107776  RCI6%$   ;Checksum

[larsbrinkhoff]

There is now a DMCG (DynaMod) document describing the format:
https://github.com/larsbrinkhoff/its-archives/blob/master/dmcg/SYS.03.02.pdf

[larsbrinkhoff]

The format is a sequence of blocks. Each block has a header word, data, and a checksum word.

The header word bits:

• 4.9 EOF. If set, ignore block.
• 4.8-4.6 LCB, loader contitional bits.
• 4.5-3.8 Block type.
• 3.7-3.1 Number of data words.
• 2-1-1.1 Address.

The checksum is a one's complement sum of the header word and the data.

Block types:

• 1 - Loader command
• 2 - Code to be loaded at address (not relocated)
• 3 - Code to be loaded at address (relocated)
• 4 - Program name.
• 5 - Library search.
• 6 - COMMON (Fortran).
• 7 - Global parameter assignment.
• 10 - Local symbols.
• 11 - Load time conditional.
• 12 - End load time conditional.
• 13 - Local symbols to be half-kiled.
• 14 - End of program, for libraries.
• 15 - Entries.
• 16 - External references.
• 17 - Load if needed.
• 20 - Global symbols.
• 21 - Fixups.
• 22 - Polish fixups.

[larsbrinkhoff]

MIDAS doesn't seem to know about block types 13-21.

[larsbrinkhoff]

STINK 201 knows all SYS.03.02 block types, plus 22-30. But 23-30 are not supported.

[atsampson]

I've found at least one feature that MIDAS and STINK know about that's not in that document: extend code 2 in a standard data block can also be used to rename or expunge symbols, depending on the value you pass. See the code in LOCGLO in STINK.

[larsbrinkhoff]

This is documented in DMCG memo SYS.03.02 "STINKING-DYNAL Relocatable Format".