by Bodo Wenzel
A tale of a GEM-based generic Gameboy emulator for the ST!
Sometime towards the latter end of last year, news began to filter
through to the Alive! UK HQ of a new and intriguing development on the
normally quiet emulation scene. A handy chap by the name of Bodo Wenzel
had taken up where the Reservoir Gods legendarily got close to, but left
off in the world of Gameboy emulation on the Atari.
Checking out his web page (patience! URL to come at the end of this
article!) indeed revealed that he was pursuing a TOS-based Gameboy
emulator. The other interesting facts that followed hard upon this, was
firstly that he was developing this as a 'template' or beta for a
Palm-pilot based Gameboy emulation, known of course, as Palmboy! The
second interesting point was, that Bodo seemed to be an ancient survivor
from the olden days of the ST scene, as a closer examination of his
website revealed that he was one of those crazy people who wrote demos
in ST hi-res mono, back in the Karsmakers/Exceptions era! Indeed, he had
resuscitated his ancient Mega ST from a dusty attic tomb, to work on
Early versions seemed to promise a fair bit, but accomplished nothing on
my normal 'default' hardware set-up, that is, the Centurbo 2 Falcon.
Even prodding around with various ways and means of getting more
'compatibility' had no result. This was something that remained
stubbornly ST-bound. The other major drawback for these early versions
was that they depended on a ST hi-res display, which still means a
minority of ST owners, even in this day and age. Of course, the Falcon
was capable of producing an ST mono hi-res display, but the program
didn't work on a Falcon (sigh!)
But what about that lovely 4MB STe that you've got at home, I hear you
all cry. Well I do have this, but it has been acting as an art deco
doorstop since last November. It was last in action at the Stafford
Computer Show, where a bearded hairy individual known as Chris Crosskey
borrowed my monitor cable "For a short while." Now the end of March is
in sight, and I have just got this monitor cable finally back in my
In the meantime, after a Mega ST meltdown inspired layoff, Bodo is back
with a new version of STemBoy, developed under the STonX ST emulation
environment. This is version 3.2.
Any good? Well, there have been some improvements, as the mono-only
restriction has been lifted, and STemBoy is capable of at least the
other available ST screen modes, and quite probably, some others
besides. Background stuff like ROM compatibility has been improved, no
doubt, and the bugs have been slapped around and shown their place in
the overall scheme of things. Does it run on Falcons and later Atari
models? Nope, afraid not, although I managed to get the menu shell
working in a stable fashion (by regressing my Falcy back to 4 meg with a
handy little prog called 'Figgy'!) It still decided to bomb out when
attempting to run a Gameboy ROM image.
With my STe restored to fully working order, I tried STemBoy again with
that. Got the menu shell up, loaded a ROM file, and IT WORKED!
I'll say a bit more on how well it worked a bit later on, but firstly, a
little bit about the physical aspects of this program.
STemBoy is GEM-compliant, and seems to run in a wide variety of screen
modes. I suspect that if the Falcon/later model Atari compatibility
problem is beaten, it should run with third-party operating systems,
such as Mint and MagiC well enough. It is also comfortable with screen
gadgets such as NVDI too. Booting up brings up a screen or console on
the desktop, where all the Gameboy action takes place. There is a menu
bar with various options at the top, so straightfoward actions such as
'load' and 'run' are immediately to hand. It is also possible to display
information on the currently loaded ROM image.
You can set up various options for the emulation, with a pure emulation,
to include checks, opcode profiling, and single step operation, or not,
if you choose. You can obtain CPU messages, presumably if it does
something illegal, and there is even a debug panel, which lets you
tinker a little bit deeper.
Loading a ROM image either results in a two bomb crash (Falcon), or
something happening in the console window (STe). For the purposes of the
review, I obtained some Gameboy Demo images from a handy and
attractively presented site linked to from Bodo's home page. Yes, there
is such a thing as a Gameboy demo scene, which seems to be closely
linked to an active homebrew game developer scene. And yes, I'll get you
that URL sorted at the end of the article as well!
A couple of these were conversions of Autodesk animations (.FLI) The
famous, if slightly cliched spinning clown's head has got a Gameboy
version. It is somewhat monochrome, but immediately recognisable to
people who were active in 1993! On an 8 mhz STe, it is not the fastest,
running at 1-2 frames a second. According to Bodo, on a stock 8 mhz
machine, the emulation is running at around 10% of normal Gameboy speed.
It does run quicker on those PC emulations of ST's, where you are able
to tap into the full power of the PC, and speed up many times. STemBoy
also checks out okay with TOS 2.06, so the Mega STe, with its 16 mhz,
should be able to do a better job with it.
I also tried an extra large Kirby sprite demo, and a Mario zoomer thing.
All worked, pretty slowly. I stayed away from any game ROM images,
figuring that faster TOS hardware would be definitely needed there!
All of the above were based on a standard (32kb) format. The one failure
thus far, was a demo using an extended ROM format, from Acorn demo nuts
Icebird, which almost worked, but gave up.
At this point in time, this emulation is starting to have real
possibilities, but Bodo announces that he is concentrating on the
PalmBoy version, and there is unlikely to be any more versions of
STemBoy! Apparently, the Linux environment that Bodo currently uses
has eliminated the need for a TOS version to act as a beta for PalmBoy.
He has put out an appeal to some kind coder to take it off his hands, at
least to sort out the later model Atari compatibility issue, so we
remain hopeful that someone will prod the source code into something
runnable on my two Falcons of enhanced abilities! Which would be extremely
Okay,the URL stuff is here now..
To get hold of STemBoy, and take a look at Bodo in general, try
To grab hold of those lovely demos, and some freeware games too (how
about a Gameboy Lemmings stylee production for example!)
It's generic! (The missing link for Godboy?)
It's GEM compliant!
It seems to be pretty compatible.
Runs (slowly) on a stock ST or STe.
Runs (more quickly) on an emulated ST.
It bombs on a Falcon or TT. (Milan etc?)
Some extended ROM images not compatible.
Author not pursuing active development anymore?
CiH for Alive! - March '00