Steven Seagal's Atari ST Web Site

Steem

"Maximum Emulation"

  Coming soon! Features, fixes, hacks, etc. for Steem SSE 3.5.2.

As you can see there are quite some "arghs" already, next version shouldn't be too long to come.

 

 
 

Option Disk drive track info

 
 

 
  Argh! In v3.5.1, the new option Disk drive track info was always checked at startup. I didn't see it because the option is useful for my tests. Fixed in v3.5.2.

Also a similar problem with option STX only for Pasti.

 
     
 

More screenshots please!

 
  On request, you will have 100,000 (wow!) instead of 1,000 available screenshots for one game, for example:  
 
Crackdown_001.NEO before

Crackdown_00001.NEO now

 
     
 

Atari Diagnostic Cartridge

 
 

 
 

 

 
  What you always desired is now reality: Steem can boot the little known Atari Diagnostic Cartridge. I downloaded the ROM files there and made a stc file (Steem's format) from those using WinHEX.  
     
 

 
     
 

Steem will also accept 64KB cartridges (like this one). And 128KB cartridges don't need to start with 4 additional null bytes anymore. Also, Steem won't hang anymore when you try to load a wrong cartridge file (it was one of the rare bugs in Steem 3.2).

Technical notes.

1) Notice it's Keyboard rev. 2. It's because the HD6301 program in ROM sends $F1 to the CPU at reset. If it sends $F0 instead then it will say Keyboard rev. 1.

2) The RAM tests won't work well if we keep the MMU confused thing disabled... so now it's back on (a good thing I used #ifdef instead of just trashing the code), and so we've finally found one use of the costly feature that affects all memory read/writes. What I don't figure is where Steem authors got that kind of information, it's one of the most obscure parts of Steem code.

 
     
 

Riverside

 
 

 
  Riverside, a recent 64KB demo by DHS, didn't display correctly in Steem.

It's because the STE-only technique used to remove the left border, line+20 bytes, causes an 8-pixels shift of the scanline which wasn't emulated yet.

Don't cry rivers, this is fixed for v3.5.2, but because the core video rendering system of Steem is in assembly and modifying it is involved, I used a hack instead, which makes the display of some other demos using the same trick (eg More or Less Zero) less elegant in the borders, only in very large display size mode. The importance of this is more or less zero, just mentioning it.

There was another problem in the lower border due to some tests not being done if the scanline wasn't supposed to be done yet even though cycles were ahead (eg. we're 516 cycles into scanline). Pure internal issue. This latter fix could very well pollute other programs, so some testing is needed.

 
     
 

General Info Box

 
 

 
     
  This is no emulation improvement, just a facility. Beside the other texts, Steem SSE will also display two SSE-specific texts: the version info (a big file already) and the FAQ, provided those files are in the Steem directory. Now you have no more excuses for silly questions!

Because those texts are formatted to be Notepad-friendly, some other mods were applied so that the experience is the same: larger box, proportional font.

For the moment with the 'SSE' icons, it could change.

 
     
 

Just Buggin'

 
 

 
  Argh! For v3.5.0 I changed the threshold for the line -106 bytes shifter trick, to see "what happens", and what happens is that the Just Buggin' menu only displayed correctly in mode wake-up state 2. This bugging mistake has been fixed in v3.5.2.  
     
 

High Fidelity Dreams

 
 

 
  Argh! A silly bug in ACIA emulation made this demo insensitive to space bar bashing in v3.5.1. Fixed in v3.5.2.

Notice the CPU trace mode, the demo is protected.

It's useless to press space bar before the rasters appear.

 
     
 

V8 Music System

 
 

 
  In Steem SSE 3.3, I had copied an insight from Hatari that made this demo work (respond to space bar). In the new version of Hatari (1.7.0), the feature has been removed and replaced with another fix, so Steem follows suit.

The previous fix was a supposed ACIA quirk, apparently it was wrong, the current fix is a MFP quirk. Gasp! This is far more liable to break programs, so it needs some testing...

 
     
 

Fuzion CD 77, 78, 84

 
 

 
  Argh! I checked those disks because they were listed as improvements in Hatari 1.7.0. They crashed in Steem, I thought it was because Steem lacked those MFP improvements. In fact no, they crashed for an unrelated reason, still the CPU fix for Aladin being trouble (since v3.5.0). The MFP thing was already in Steem when Steem authors released the source.

Notice that there's a wrong disk image of Fuzion 78 circulating (the [a] in TOSEC).

I also realised that Aladin was already broken in v3.5.1... Hopefully this is all restored for v3.5.2!

 
     
 

Mindbomb/No Shit

 
 

 
  Argh! To have SNYD/TCB demo working, I had to "hack" the read shifter counter function, and this broke this screen (since v3.3). Fixed in v3.5.2.

TCB still works, it's more a hack than ever though, I don't quite understand what's the real problem, and so you need use option 'Hacks' for TCB now.

 
     
 

Delirious 4 fake GEM

 
 

 
  There! We get the mouse centered again. It was in v3.5.1 too but at the price of broken Hifi dreams.

There are two deliriously fast successive writes into the ACIA TDR register. The second one hits when the ACIA is still transferring the first byte to the shift register and it is ignored. If the program had checked the SR register, it would have known that the TDRE bit wasn't set yet. Just a theory but it makes sense for the moment. We count a delay of 512 CPU cycles before a write to ACIA TDR will work again. Note: I think the feature was already in Steem 3.2 somehow but lost among all the ACIA/IKBD mods.

Update: this fix has been disabled as even on a true ST the cursor isn't centered. }:(

 
     
 

European Demos

 
 

 
  Floppy drive emulation improvement or... hack. Like the screen above, this one isn't so easy to obtain (choose demo Pendrag I). Check option 'Hacks' for this...  
     
     
     
     
     
     
     
     
     
     

 

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