Gnusto-Frotz-Tops20

Status

It seems to play the Infocom games and a smattering of community-written Z-code games.

It passes the tests in czech but not all the ones in praxix; behavior on the test suite seems to match dumb-frotz 2.32 for Unix.

The Reason It Wasn't Trivial

@type testc.c
#include <stdio.h>
int main ( int argc, char **argv) {
    char c=-1;
    short s=-1;
    printf("Max unsigned char is %d\n", (unsigned char) c);
    printf("Max unsigned short is %d\n", (unsigned short) s);
}
@cc -o testc testc.c
KCC:   TESTC
 "testc.c", line 8: [Note] Parameter "argc" not used
       (main+6, p.1 l.7): "Max unsigned short is %d\n", (unsigned short) s); }

 "testc.c", line 8: [Note] Parameter "argv" not used
       (main+6, p.1 l.7): "Max unsigned short is %d\n", (unsigned short) s); }

<ADAM>TESTC.PRE.4
<ADAM>TESTC.FAI.4
FAIL:  TESTC
LINK:  Loading
@testc
Max unsigned char is 511
Max unsigned short is 262143

And this line in the Dumb-Frotz README, in the CAVEATS:

     - lack of 8-bit char and 16-bit short.  I didn't bother to think
       much about this.  If you're using a 36-bit Honeywell or
       something, let me know.

Introduction

What?

This program has only one function: create a version of dumb-frotz that is playable on TOPS-20 on a PDP-10.

It does this by acquiring a fork of dumb-frotz 2.32r1, transmogrifying it so that the TOPS-20 linker can handle the symbols, and outputting the mogrified sources.

This isn't as easy as it sounds, because:

[https://github.com/PDP-10/panda/blob/master/files/kcc-6/kcc/user.doc#L519]

However, the situation is different for symbols with external
linkage, which must be exported to the PDP-10 linker.  Such names are
truncated to 6 characters and case is no longer significant.

So you need to map all the symbols in the header files, everything declared "extern" in the source files, and also make sure that your input file names are unambiguous and no more than six characters before the extension.

But even that's not enough, because there are a number of places where Frotz is assuming 8-bit chars and 16-bit shorts. So now gnusto-frotz-tops20 pulls from my fork of the sources at https://github.com/athornton/tops20-frotz, where I've been hacking to sanitize the code such that TOPS-20 is happy with it. I think I have finally succeeded.

Why?

To bring Zork back home.

More generally, with the dump of "The Infocom Drive" showing up on the Internet, I decided it'd be fun to be able to play Z-machine files on a PDP-10, as God and Nature intended.

License

Gnusto-Frotz-Tops20 is MIT licensed.

Copyright 2019 Adam Thornton [email protected]

Usage

You will need a Perl 5 interpreter with the standard Perl libraries, a working sed, and a working git. You will need to be in a writeable directory.

Generating compilable source

In there, just execute gnusto-frotz-tops20. This will generate a bunch of files in the output directory.

Compiling that source

Copy those files to a TOPS-20 system (e.g. FTP in text mode) that has KCC installed, and compile them with cc -o frotz *.c. That will generate frotz.exe, which is the TOPS-20 executable.

I'm using the late Mark Crispin's "Panda" distribution of TOPS-20 and the klh10 interpreter.

Running a game

From the directory containing frotz, frotz <directory>game does the trick.

Future steps

I presume there's an OK curses library for KCC, although I haven't looked. The PDP-10 certainly should be able to talk to a VT-100 or one of its successors, so we should be able to do a pretty decent representation of all the non-graphical games.