Steven Seagal's Atari ST Web Site

Steem

"Today You Hack"

  Coming soon! New fixes for Steem 3.4.

 

 
     
 

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.  
     
 

36.15 Gen4 by Cakeman (STF)

 
 

 
  This program failed because the VBI (VBL interrupt) and the left border trick timings are different for STF. It's all been arranged for v3.4. Cool effects but it's in French.

This demo is also called 3615 Gen4 like the one by ULM because it was a (French) contest. There are many more.

 
     
 

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.  
     
 

Extreme Rage (STE)

 
 

 
  Using the best ST debugger around (and some TRACEs, of course), I found out why we were missing the overscan logo on this screen, which put us in such extreme rage.  
     
 

Golden Soundtracker (STE)

 
 

 
  Not a golden fix, still not a great screen, but it's more accurate we may hope. The flickering background colour was wrong (?). A rather silly effect by the way, but it pointed to a possible problem, so fine.

As usual, I had to redo the fix once or twice to get it right (if it's right, of course).

Some versions of this disk crash when you select tracks F5-F10, maybe one side wasn't copied; the version at pouet.net is OK.

 
     
 

Goldrunner

 
 

 
  Welcome to the... Wait! There was nothing to fix? In fact, a little mod to the low pass filter makes music sound better, although it's subjective. And I wanted to put this great game on the site anyway, so it's a good pretext. I also prefer the BIG demo opening tune with this filter. The former filter was perhaps overkill, too muffling. This one is halfway between the former one and the 'direct' mode. With this little change, YM-2149 emulation sounds the best in Steem, but maybe I'm biased. If you don't like it, unchecking the 'STE Microwire' option restores the original filter and volume. When this option is checked, YM-2149 chip sound should also be 6db quieter, except for samples, to make transitions from STF sound to STE sound (a bit) less harsh.

This game is best played in fullscreen with a correct display (50hz or 100hz).

 
     
 

Mortville Manor

 
 

 
  There was a major hiss issue in this game, probably others (v3.2). Also, the option "sharp STFM samples" has become rather useless, with the new filter samples sound clear enough with the common option, which I renamed "Simulated Monitor Speaker" (instead of "ST speaker").

I'm afraid I can't make the French accent disappear, nobody can. Just play it in French!

 
     
 

Display options

 
 

 
  I looked again at the "very large borders" mode. Since there's a shift of 4 pixels in overscan, it seems that only 412 pixels are necessary and not 416. This avoids the ugly little border on the right side of the picture. For example here:  
 

 
  Ain't it nice? I think this way you really get the beST in Steem's very large display mode: the full useful picture, and it's still cool to behold. Still testing as it's yet another hack in the system.  
     
 

Reality is a Lie (STE)

 
 

 
  This is the Schnusdie screen. The logo in overscan was wrong. Maybe it still is, seems a bit shifted on the right. Looks like another case of left border removal, working now with some more hacks and patches.  
     
 

Death of the Left Border, Omega Full Overscan (STF2)

 
 

 
  Steem 3.3 already claimed those early demos, but I think the fix makes more sense in v.3.4: on a STF, a late shift mode switch without stabiliser shifts the screen by 4 bytes, what a fine theory, hey I try! And it would only work when the STF is in "wake up state" 2. Now the alignment of both demos looks right in 'normal' and 'very large' display sizes.

The hack for Omega in v.3.3 was so outrageous (the concept of sync distortion was bogus) because Steem got the wrong cycles due to 508 cycles lines. It's hard to fix in general without breaking everything.

What is still not emulated is shifter confusion on many STs running those programs (see the interesting screen on a previous page).

 
     
 

HighResMode (STE)

 
 

 
  Argh! I wasn't aware that this 29.791 colours demo (their brag; such pics look better live due to the trick) used to perfectly run in Steem 3.2. I wasn't aware that it was broken in that buggy SSE 3.3. In fact I thought it was a monochrome demo and left it aside until now! There was also an issue with the disk image. The observant will notice it is the second feline in this page.  
     
 

Hidden Agenda (STE)

 
 

 
  Argh! My patch for the Super Neo Demo Show broke 14MB recognition in v.3.3. Nice coding dude! Though I regret nothing, better run the demos from the coolest dudes (TEX) first.  
     
 

European Demos boot

 
 

 
  The protected version loads in Steem now (since v.3.3). It's still the same fix as for Phaleon that pays up. In v3.4, this fix is less of a hack. It's not based on the precise opcode anymore, it's more like a general bug-fix at microcode level! Thanks to the way Steem's cpu emulation was coded. Still testing though.  
     
 

Blood reset screen

 
 

 
  A SSE version without bugs HACKS?!? Stop the madness!!!! No way! You just need to check the funny 'Hacks' option and not worry about the rest. It's useless because the demo was already OK with Pasti, but it's fun messing in drive emulation.

Fun but dangerous. All the "fdc" hacks don't operate if the 'Hacks' option is unchecked. Madness must stop somwhere.

 
     
 

TOS106

 
 

 
  I recently discovered the nasty bug in TOS 1.06 (or 1.6). It was corrected in 1.62 (which isn't a major revision but a bugfix, even if the numbers are a bit confusing). The bug is that when you reset, the STE displays the desktop in low res although it was saved in med res. Pretty lame. Shows a lot about dedication. It wouldn't have taken much testing to find it. Two years to plan the STE and they rushed it like that.  
 

 
  It's a useless fix as TOS 1.62 is fine, but I hacked it anyway... an odious patch, as I don't quite understand how it works. I tried to change the TOS to no avail, so we intercept the DESKTOP.INF instead. Ouch! A really stupid hack for a really stupid bug. You don't want to know how much time I've already wasted on this. This is fun.  
 

 
  This screen is also the occasion to compare PC green with ST green (as emulated and copied to other software anyway!).  
     
 

HD6301 true emulation

 
 

 
  Well, I'm working on it anyway, don't know when it's ready. The Hitachi HD6301V1 was the keyboard controller (IKBD) in the Atari ST, it was a full-fledged 8bit processor. In the current version of Steem, it is (very well) emulated on an input/output basis. It would be better to emulate it on a low level. It is very possible. I found some doc, a rom dump, a (very old, but the chip ain't new either!) M68xx emulation in C (which is always trouble interfacing with C++, hello extern "C"), and even a picture of the chip.

Integration in Steem is going on. SSE 3.4 will be released when this integration is a bit satisfying.

 
 

 
  Getting the GEM desktop slowly beginning to work with this 6301 emu was kind of moving!

It proves to be the most interesting hacking I've been doing in Steem yet, even funnier than all those video shifter tricks.

There's still more debugging and tuning to do, but it did what I wanted pretty soon.

 
 

 
  You could already behold those screens in Steem SSE 3.3, thanks to the Hatari hack. Version 3.4 does it thanks to the (3rd party) 6301 emu.  
 

 
  Those are the only ones guaranteed to run for the moment!  
 

 
  That's why it's optional, fake IKBD emulation is generally better (note: I plan to change the option design, this one is strange there).  
 

 
  As a side note, while not trivial, it seems less work doing this than guessing the 6301 behaviour and emulating all its commands on an I/O basis.

That job has been done however, and I also messed with it. Plus, true emu is more CPU intensive. We should keep the option, with hopefully very similar results.

 
 

 
  Now adding the great Barbarian to this puny list, it was quite the debugging quest.

The Psygnosys IKBD issue is a way to check our timings and ACIA tuning, which are probably still wrong.

 
 

 
  Who would believe that a grown-up action man pass his time checking the ST mouse speed? Getting a fast enough mouse to save your skin in Arkanoid (still a bit sticky!) was trouble enough, and it was even more trouble getting it slow enough to draw in the unforgettable NEOchrome, for example. Mouse speed is really tricky. What we have is still far from perfect, it seems we should improve the timings before tinkering further. By the way, the mouse reacts differently in the upper screen of NEOchrome.  
 

 
  Everybody remembers the cooool conversion of Gauntlet on the ST. Now the funny "mouse instead of joystick" bug is reproduced, our wizard even went through the wall! Gauntlet, Barbarian, those were the days!  
     
     

 

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