The "original" Colossal Cave Adventure for Windows
==================================================

A few days ago I stumbled upon Dan Nelson's port of the original PDP-10
FORTRAN source code by Crowther and Woods /1/ to ANSI FORTRAN 77 /2/ in
the Interactive Fiction Archive.

Unfortunately, I couldn't find a pre-compiled Windows binary or at least
a DOS executable for running in DOSBox /3/ of this port. And yes, I want
'to play the original colossal cave adventure in its true original form,
with no omissions, additions, or modernizations' /4/ in a modern Windows
environment.

Therefore, I started my own short adventure in compiling this piece of
history for Windows.

As Dan suggested, I compiled his port using g77 which is available in
various versions for Windows on the internet.

I changed the path to the binary state file from '/etc/advent.bin' to
'advent.bin' for obvious reasons. The state file resides now in the
executable directory. Therefore, write permissions to this directory are
required, when using magic.

g77 did compile Dan's source files out of the box without any problems.

But I realized that g77 is fairly old and the compilers I found did only
create win32 executables. I checked the net for more modern GNU Fortran
compilers and ended up with several versions of gfortran (MinGW and
MinGW-w64 environment).

gfortran threw several warnings and errors during the first run. I did
suppress the warnings regarding obsolete features using the option
-std=legacy. For solving the compiler errors I had to change only a
few lines, especially the format argument in the WRITE statements for
issuing error messages when reading and writing files as well as one
sloppy written continuation line. Clive Page's Professional Programmer's
Guide to Fortran77 /5/ helped me find my way. The changes are documented
in the unified diff files.

I tested several versions of gfortran (7.4.0, 8.3.0, 9.2.0 and an
experimental relase of 10.0.0). All versions of gfortran (as well as
g77) did compile the changed source files without any problems.

I decided to use gfortran 9.2.0 for building x86 and x64 releases with
static linked libraries. The resulting executables have been packed with
UPX 3.95w /6/.

This archive contains following files:

advent.dat        data file converted by Dan Nelson
advent.dat.orig   original data file by Crowther and Woods
advent.for        updated source file for advent
advent.for.orig   original source file by Crowther and Woods
advent.unidiff    unified diff file documenting my changes to advent.for
datcvt.for        source file for data file converter by Dan Nelson
make.bat          batch file for compiling advent and wiz (gfortran)
make-g77.bat      batch file for compiling advent and wiz (g77)
README            README by Dan Nelson
README.win        this file
wiz.for           updated source file for wiz
wiz.unidiff       unified diff documenting my changes to wiz.for

x64\advent.dat    Pre-compiled Windows binaries (x64)
x64\advent.exe
x64\wiz.exe

x86\advent.dat    Pre-compiled Windows binaries (x86)
x86\advent.exe
x86\wiz.exe

The binaries have been successfully tested on Windows XP SP3 (x86 only),
Windows 7 SP1, and Windows 10 Pro 1903.

Thanks to Dan we are able to play our beloved Colossal Cave Adventure in
it's true original form (at least until the year 2101; see Dan's comment
in SUBROUTINE DATIME). As long as future GNU Fortran Compilers support
FORTRAN 77 it will be possible to compile executables not only for UNIX
environments but also for Windows operating systems (and others as well,
of course.)

Thank you very much, Dan!

Hartmut Kuehne
Dec 14, 2019


Update: "You fell into a pit..."
================================

Of course, it had to happen: When compiling the sources with gfortran
9.2.0, I did fall, full of confidence, into a pit prepared only for me
by the developers of the gfortran compiler. I did not break my neck, but
the random number generator. No dwarfs, no pirate, no escape from Witt's
End...

According to the documentation of gfortran 9.2.0 /7/, the compiler does
provide an intrinsic function RAN as alias for RAND for compatibility
with HP FORTRAN 77/iX. This intrinsic function has been called instead
of advent's own random number generator function RAN. After declaring
RAN as external procedure (EXTERNAL RAN) the dwarfs did return!

This archive contains now the updated sources and binaries.

Jan 04, 2020.


References:

/1/ https://www.ifarchive.org/if-archive/games/source/advent-original.tar.gz
/2/ https://www.ifarchive.org/if-archive/games/source/advent-orig-nelson.tar.gz
/3/ https://www.dosbox.com/
/4/ see README by Dan Nelson
/5/ Page, Clive G.: Professional Programmer's Guide to Fortran77
    https://www.star.le.ac.uk/~cgp/prof77.pdf
/6/ https://upx.github.io/
/7/ https://gcc.gnu.org/onlinedocs/gfortran/RAN.html