palbart - BART enhanced PDP8 crossassembler

palbart [options]inputfile

This manual page documents briefly the palbart command. It is a cross-assembler to for PDP/8 assembly language programs. It will produce an output file in bin format, rim format, and using the appropriate pseudo-ops, a combination of rim and bin formats. A listing file is always produced and with an optional symbol table and/or a symbol cross-reference (concordance). The permanent symbol table can be output in a form that may be read back in so a customized permanent symbol table can be produced. Any detected errors are output to a separate file giving the filename in which they were detected along with the line number, column number and error message as well as marking the error in the listing file.

The following file name extensions are used:

.pal source code (input)

.lst assembly listing (output)

.bin assembly output in DEC's bin format (output)

.rim assembly output in DEC's rim format (output)

.err assembly errors detected (if any) (output)

.prm permanent symbol table in form suitable for reading after the EXPUNGE pseudo-op.

A summary of options is included below.

-d

Show symbol table at end of assembly

-h

Display help.

-l

Allow generation of literals (default is no literal generation) Show version of program.

-p

Generate a file with the permanent symbols in it. (To get the current symbol table, assemble a file than has only a $ in it.)

-r

Produce output in rim format (default is bin format)

-v

Display version information.

-x

Generate a cross-reference (concordance) of user symbols.

Assembler error diagnostics are output to an error file and inserted in the listing file. Each line in the error file has the form

<filename>(<line>:<col>) : error: <message> at Loc = <loc>

An example error message is:

bintst.pal(17:9) : error: undefined symbol "UNDEF" at Loc = 07616

The error diagnostics put in the listing start with a two character error code (if appropriate) and a short message. A carat '^' is placed under the item in error if appropriate. An example error message is:

17 07616 3000 DCA UNDEF

UD undefined ^

18 07617 1777 TAD I DUMMY

When an indirect is generated, an at character '@' is placed after the the instruction value in the listing as an indicator as follows:

14 03716 1777@ TAD OFFPAG

Undefined symbols are marked in the symbol table listing by prepending a '?' to the symbol. Redefined symbols are marked in the symbol table listing by prepending a '#' to the symbol. Examples are:

#REDEF 04567

SWITCH 07612

?UNDEF 00000

Refer to the code for the diagnostic messages generated.

Only a minimal effort has been made to keep the listing format anything like the PAL-8 listing format. The operation of the conditional assembly pseudo-ops may not function exactly as the DEC versions. I did not have any examples of these so the implementation is my interpretation of how they should work.

The RIMPUNch and BINPUNch pseudo-ops do not change the binary output file type that was specified on startup. This was intentional and and allows rim formatted data to be output prior to the actual binary formatted data. On UN*X style systems, the same effect can be achieved ing the "cat" command, but on DOS/Windows systems, doing this was a major chore.

The floating point input does not generate values exactly as the DEC compiler does. I worked out several examples by hand and believe that this implementation is slightly more accurate. If I am mistaken, let me know and, if possible, a better method of generating the values.

This assembler was written to support the fleet of PDP-8 systems used by the Bay Area Rapid Transit System. As of early 1997, this includes about 40 PDP-8/E systems driving the train destination signs in passenger stations.

This assembler is based on the pal assember by:

Douglas Jones <jones@cs.uiowa.edu> and

Rich Coon <coon@convexw.convex.com>

See the symbol table for the set of pseudo-ops supported.

See the code for pseudo-ops that are not standard for PDP/8 assembly.

Refer to DEC's "Programming Languages (for the PDP/8)" for complete documentation of pseudo-ops.

Refer to DEC's "Introduction to Programming (for the PDP/8)" or a lower level introduction to the assembly language.

If you don't like it the way it works or if it doesn't work, that's tough. You're welcome to fix it yourself. That's what you get for using free software.

This is free software. There is no fee for using it. You may make any changes that you wish and also give it away. If you can make a commercial product out of it, fine, but do not put any limits on the purchaser's right to do the same. If you improve it or fix any bugs, it would be nice if you told me and offered me a copy of the new version. Gary Messenbrink <gam@rahul.net>

Version Date by Comments

v1.0 12Apr96 GAM Original

v1.1 18Nov96 GAM Permanent symbol table initialization error.

v1.2 20Nov96 GAM Added BINPUNch and RIMPUNch pseudo-operators.

v1.3 24Nov96 GAM Added DUBL pseudo-op (24 bit integer constants).

v1.4 29Nov96 GAM Fixed bug in checksum generation.

v2.1 08Dec96 GAM Added concordance processing (cross reference).

v2.2 10Dec96 GAM Added FLTG psuedo-op (floating point constants).

v2.3 2Feb97 GAM Fixed paging problem in cross reference output.

v2.4 11Apr97 GAM Fixed problem with some labels being put in cross reference multiple times.

This manual page was written by Vince Mulhollon <vlm@debian.org>, for the Debian GNU/Linux system (but may be used by others).