Steven Seagal's Atari ST Web Site


"A Dangerous Dude"

  Here are some more demos normally running better in Steem.



36.15 GEN4 by ULM


  YEEEEEAAAAAHHHHHH !!! Steem 3.4 displays this demo's scroller a bit better than before.

The scroller was torn at the middle because to save RAM, the video RAM is being modified just after having been fetched, hence some emulation difficulties. The way Steem renders video can sometimes be a pain, but in this instance it's a blessing, it was an easy fix (but targeted to save performance), and it troubles some people!!!

Update: There was a glitch in the left border though, and I wondered if it was so in the demo or an emulation bug. The test has been improved in v3.5.3 and there's no more glitch. Not only that but the test is more general now, and normally it should handle other eventual cases. YEEEEEAAAAAHHHHHH !!! (*)

(* about those YEEEEEAAAAAHHHHHH !!! it's just how the demo starts, I'm not such a braggart!)


Download 36.15 Gen4 by ULM


Beat Demo (STE)


  One of the rare programs using the STE Microwire feature, now emulated thanks to third party DSP code.

update: treble control not operating in current version


Big Wobble (STE)


  This is another 'write to SDP' difficulty in a quite technical demo, one day we will figure it out for real, before that we make do with hacks. It's worth it: ain't that tiger cute?

Hack was refined in v3.5.1 so as not to break Armada is Dead.


Download Big Wobble


Cool STE


  This is a demo that was nearly lost. It's a shame because both the concept and the music are cool (I enjoyed listening to the music while fixing Steem for it). The scrollers are lame though.

There were two problems in Steem:

- Heavy flicker due to borderline timings interfering with what I identified as some Steem hacks! Note that I'm not sure it wasn't flickering on some true STE.

If there's still some flicker in a particular version of Steem, this patch should fix it.

- STE horizontal scrolling not handled in medium resolution (well this is the only case I know).

The video rendering is better now (v3.4).


Download Cool STE


Corporation Megademo (STE)


  This demo could very well bust some part of your anatomy. Maybe it didn't work on purpose before, to protect you. The keyboard hits are taken now (v3.4). Because the fix can interfere with other programs, for a reason I haven't figured out yet, it needs the option 'Hacks' to be enabled.

More recently I found that it may work without the hack, if option 6301 true emu is checked.

Notice that there are bad images of this disk floating around.


Dangerous Fantaisy: credits (STE)


  Another case of SDP (video counter) issue, the lower ST (ST and not STE) flickered. Still looking for more general rules. The question is when Display Enable (DE) exactly starts and stops. Fixed in v3.4.


E605/Planet by Light (STE)


  At first I thought it was amateurish coding compared with the similar Overscan Demos #1 because the planet was cut in half and came on the left and on the right of the screen. But it was in fact an emulation issue (another damn instance of write to SDP). The overscan was trouble too. It was worse in my version of Steem SSE 3.3 than in v3.2. It's apparently all "fixed" (hacked in fact) now (v3.4), but it's an interesting case to further probe.

This is another cool STE demo after all... the stereo sound is at 25khz. The picture is exactly the same as in Overscan #1, only bigger. Some fine "Jarresque" music comes on later screens.


European Demos


  The protected version loads in Steem now. It was easy to fix, just add a case (like, really a C case), to something already handled by our favourite emulator (v3.3).

In v3.4, this fix is less of a hack. It's not based on the opcode anymore, it's more a bug-fix at microcode level, believe it or not! This is made possible by the way CPU emu was coded by Steem authors.



Extreme Rage (STE)


  Only one screen had a problem, the guest screen missed the overscan logo, which put us in such extreme rage. There was a little something to fix in the excellent blitter emulation of Steem. So now here I'm bragging like a dick... but I didn't write the blitter emu, Steem authors did!




  She knows!

A note on the demo: it starts very impressive, but the numerous scrolling pics quickly get boring.




More or less Zero (STE, 2MB)


  Like Anomaly, Braindamage, Froggies, Punish your Machine and too many others, this demo doesn't understand "drive B". It's possible they didn't want anybody to skip the nice request pic. It also uses an overscan technique peculiar to the STE that wasn't emulated in Steem yet (but it was in Hatari), the 224-byte line. Matters get more or less complicated when STE scrolling is involved as well (Spiral screen, maybe the best):  


Don't forget to set the memory to 2MB (the same for many STE demos).


The Musical Wonder 1991 (STF)


  Not a great wonder, just a case of left border removal timings that only worked on STF. Oddly, the 1990 edition worked on STE as well as on STF.


NGC (Delirious 4 STE)


  The rasters are nice (and in overscan) but the logo and the text in "plazma" suck. Anyway, the display in Steem 3.2 was horribly wrong. It's because the demo features a kind of 4bit scrolling (the "new technic") and a very odd (buggy?) 0 byte line that shifted the graphic... and my mind.

Note: logo may be shifted on real STE


Nightmare (Delirious 4 STE)


  The nice Nightmare screen features 4bit scrolling like ST-CNX, but more difficult to emulate - at least for me. One could say it was a... nightmare! The scrolling is certified smooth emulation-wise. Shows better in 'normal' display size mode.


No Cooper Greetings


  A screen in medium resolution overscan, not quite as cool as BPOC. Large display isn't necessary but a strange plane shift is. I suspect that's because the shifter is half loaded or something when the shift mode switch occurs.


Omega Full Overscan (STF WU2)


  This screen doesn't look like much but it's another milestone demo running in Steem, thanks to disgusting hacks in v3.3, to more acceptable ones in v3.4 (as an excuse, there already were hacks in v3.2, hard to get around).

To access the real demo, do a warm reset (right-click on the power button). Then endure the intro (or fast-forward, thanks Steem authors for that!), choose the demo with side arrows and start it with 'Help' ('page up' on the PC), then watch in awe this Steem exclusive (AFAIK). This is the first "fullscreen" demo in prehiSTory, but it was very unstable (in v3.4 choose option wake up state 2). Here's how it typically runs on a true ST, so don't nit-pick about Steem rendering:


  On the screen above, we see distortion caused by the amateurish removal of the top border (sorry dudes!). You can also see that half the display is missing on all lines in a strange way, because the shifter is very confused... That's what happens when you don't reset it every line and your ST is still cold! One day we could try to emulate this behaviour (as an option)!  

  V3.5.3: done! Option Shifter panic.


The Overscan Demos


  I suppose the author would have us believe this is his girlfriend... Those fine demos (STE version) already worked perfectly in Steem 3.2 but they may benefit from a larger display, such as 413 pixels wide.  


That's a screenshot of a CRT display I took myself.

If you check left and right borders, you see that they are cut at the same pixel: in "fullscreen" overscan, 413 pixels are visible per scanline, starting from the very first one in the left border. So there's no "4 pixel shift."

Spectrum-like pics like this one are demanding for Steem because this emulator renders part of the screen each time there's a palette change. It does work, it just requires some more CPU cycles.

There are small dots on a real STE. This is emulated in Steem SSE (WU2).

Note that the moving (after a while) Atari symbol is not an emulation glitch like I thought but a feature of the demo!

The older (STF) version didn't work in Steem 3.2.


Download Overscan Demos (STF+STE)


Download Overscan Demos STF


Pacemaker: credits (STE)


  There was a glitch due to changing the video counter while the line is being drawn.




  Like for Dragonnels, a CPU timing problem prevented it from loading in Steem, this time DIVU, as part of the protection.


Reality is a Lie (STE)


  This is the Schnusdie screen. The logo in overscan was wrong. Looks like another case of left border removal, working now with some more hacks and patches (v3.4).


Swedish New Year Demo 1989 (STF)


  This is the TCB screen (F2). Now, OK, it isn't that great but that's what you got from Sweden (they did better too) and a fix is a fix. Believe it or not, it's better than before! You couldn't see the logo previously. It's easier live but normally you should be able to spot it on the screenshot - a good eyesight test. The digi sound already worked fine.  

  V3.5.3, option Wake-up state 2 will have the logo centred!

V3.8.0: the hack has finally been removed thanks to GLU/MMU refactoring.


Swedish New Year Demo 1990 (STF)


  The Sync "in your face" fullscreen (F5) was STF-only. It shows poorly with larger borders (correct emulation).

This screen has been redone for STE, here.


Tekila (STE)


  This strangely named demo is one of the numerous demos of Delirious IV that didn't work in Steem (I suspect the Steem authors never laid their eyes on these). This one uses STE scrolling and write to the shifter draw pointer while the video memory is still being drawn. It's not so easy to emulate.

Is this graphic worth the trouble? I let you judge when you're sober. Though watching this demo won't make you sober, delirious tremens isn't far:



Ultimate GFA Demo (STF)


  The boot screen of this interesting demo has shift mode switches to mode 2 at cycle 508 (except on the lower overscan line) and then at cycle 4. I think it was rendered correctly for an STE in Steem 3.2 (broken lower overscan), but that it showed as above on an STF.

Update: in fact rendering was incorrect for STE as well. Display is shifted and right border is missed. This is correct in v3.8.0.


V8 Music System


  This fine demo needed a patch in Steem 3.2 to activate.

That's because there's a small latency when the MFP (MC68901 Multi-Function Peripheral) requests an interrupt, the processor doesn't see it at once (from Hatari).

Notice that the colours are different in STE mode.

Update: v3.7. It still works, but the theory is different. If the GPIP input has just transitioned, IRQ hasn't fired yet.

Note that before, the theory was a delay inside the ACIA chip.



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