README.axp

Exult on Alpha/Linux
--------------------


Running Exult on Alpha/Linux has no special restrictions, but compiling
it does, since the current (2.95.2) g++ is known to be broken on this
platform. This document discusses how Exult can be built on the Alpha
anyway.


1. Problem description
----------------------
GCC's g++ frontend on Alpha/Linux is, simply put, broken. This is very visible
when using code optimization, but even without optimization, incorrect virtual
function tables are being generated. This doesn't happen everywhere, but it
affects Exult; therefore, compiling Exult can't be done with g++ at the moment.

Compaq has provided us with an alternative, though: DEC's cxx compiler, ported
to Alpha/Linux. This compiler is non-free, but available without charge from
their website. Unfortunately, most Linux system headers appear to be set up for
g++, which does some magical internal name mangling. This doesn't conform to
the standard, but, more importantly, it breaks cxx, unless names are mangled
manually.

cxx has two other problems: It does not appear to like static methods that use
templates, and its object files don't work with many versions of ld
(specifically, it requires ld to accept --style=compaq. All modern ld versions
from the GNU binutils claim that they do, but most of them are lying).

Finally, ladebug appears to be either too slow or- in some way (multithreading)-
incompatible with Exult or one of the libraries (SDL?) used by it.

Sections 3 and 4 will discuss how these problems can be worked around.

As far as I know, all other issues are general 64 bit cleanness issues.


2. Updates and binaries
-----------------------

Up-to-date information about Exult on Alpha/Linux and pre-compiled binaries
can be found at

http://www.darmstadt.gmd.de/~jameson/exult/


3. Preparing for the compilation
--------------------------------

First, I'd like to point out that it may take a while until your system meets
all preconditions required for compiling Exult. If you just want to play the
game, it might be easier to use a pre-compiled binary from the URL mentioned
in section 2.

All right, if you're still reading this, you appear to be seriously considering
to compile the beast. Here's what you'll need:

- Compaq cxx for your Alpha/Linux flavor
- Compaq's libots

Compaq ccc might be required as well; I had it and cpml installed, too
(just in case).

Refer to

http://www.support.compaq.com/alpha-tools/software/index.html

for instructions on downloading these tools for non-commercial usage.

Also, you'll need to link the generated object files. As discussed in section 1,
your version of ld might not cut it. Try running "ld --style=compaq"; if you get
an error message, you'll need a different version.
I copied mine from one of the Compaq Test Drive systems, which you can get a
free account for. Matching versions of the GNU binutils should be available
in a more official way from Compaq somewhere; please contact me if you're found
a place that carries them.

If you got a new ld, you will need to replace yours with the new one. Remember
to make a backup first!


4. Compiling
------------

./configure --enable-long-long-warnings --with-cxx="cxx -O5 -D__inline__=inline"

should do it for normal compiles. If you want to debug, you should use "-g3"
instead of "-O5", or an appropriate combination of both (refer to the cxx
man page for details).

The --enable-long-long-warnings is required because cxx passes the
-Wno-long-long option on to the linker, which chokes on it. Therefore,
-Wno-long-long must not be used for compiles, which is enforced by the
--enable-long-long-warnings option.

If everything went well, your system should be set up for compilation. Run
"make" and (as superuser) "make install". Some sort of "make install" or
equivalent action is required for Exult to install its own data files.

You should now have an "exult" binary ready to run!



-- Christoph Reichenbach <jameson@linuxgames.com>

Please contact me if you find any of the information contained herein to be
wrong, incomplete, or misleading.


[Last updated on 12/08/2000]