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Area 5150 for IBM PC 4.77MHz

EMS an option?

No, but perhaps it can help indirectly if your board and drivers let you use it as UMBs (or even just the page frame window) to free up more conventional RAM... I've seen reports about that being possible on a PC/XT.
Supporting EMS directly would be cumbersome and probably not as effective as having the same amount of contiguous conventional memory. Although the loader's memory management is Trixter's purview, so he could correct me if I'm wrong. :)
 
First all, congratulations to all the creators of this mind blowing demo. I think it's the most amazing one I've never seen, given the theoretical limitations of the platform choosen. You, guys, did what seemed impossible: even surpass 8088 mph!

VileR, I'll take your word for it and I'll start with a little barrage of questions, if you guys want to answer some of them ;-)

So here come the first topic. The Marble Madness part:

- What mode is made with? Is it also "ANSI from hell"?

- How did you do the vertical scroll, and specially the horizontal scroll, without side glitches (like in Prohibition or Boulder Dash)? Does it has something to do with the overscan? AFAIK, the CGA controller doesn't have a logical width register, like EGA/VGA's, which allows to update the next scroll's column in advance while hidden from sight. So, while CGA lacks this feature, how can this be done horizontal scroll without seen how the columns are being updated on the fly?

I'll make only a battery of questions, a topic, at a time.

Thank you everyone!
 
Sorry, I forgot to ask one more question about Marble Madness:

Would it be possible to make it interactive? In other words, would it be possible to make a full port of the arcade machine?

Thanks again!
 
Would it be possible to make it interactive? In other words, would it be possible to make a full port of the arcade machine?
You can bet there are not enough CPU cycles left for any game logic.

Also, the CGA port of the game didn't look that bad. They made good use of the colors.
 
Just got a chance to see the demo in action. I downloaded it Saturday but didnt try till just now. Good thing I D/L it Sat as today the link wouldnt work for me. Dunno. Truly incredible Demo. You guys do great work keep it up!

And maybe its me the but initial chip tune music that plays after the initial Text/color portion in the beginning sounds very similar to Life of a pixel. I know I have spent a ton of hours playing that game. Im not saying anyone stole the music, It just sounds similar and my ear caught it.
 
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- What mode is made with? Is it also "ANSI from hell"?

- How did you do the vertical scroll, and specially the horizontal scroll, without side glitches (like in Prohibition or Boulder Dash)? Does it has something to do with the overscan? AFAIK, the CGA controller doesn't have a logical width register, like EGA/VGA's, which allows to update the next scroll's column in advance while hidden from sight. So, while CGA lacks this feature, how can this be done horizontal scroll without seen how the columns are being updated on the fly?

Yes, that's "ansi-from-hell" at 80x100 characters. That's why the tiles weren't simply converted from the arcade version (they had to be redrawn for optimal use of the fixed CGA charset). Are you saying you see visual glitches when Prohibition/Boulder Dash scroll sideways? I don't remember them glitching at all on my CGA, although I guess I could check.

The horizontal component in the Marble part scrolls pretty much the same way those games do; you don't really need the logical width to be different from the display width. When you hardware-scroll by modifying the video start address, you're exposing a column of video RAM that doesn't have the right data (yet). But if you time it right, you can update that column with new content before the CRT starts scanning the next frame (with its new start address). So by the time that column is actually drawn on screen everything is already in place.
So the principle isn't really new. The difference here is that 80-column mode lets you scroll sideways at finer increments, but the tradeoff is that you also have to avoid 'snow' (in addition to wrong-content glitches).

The "special" bit here is actually the vertical component - it scrolls at a single scanline per frame, and you can't do that in a full-screen CGA mode by changing the start address alone. (Feel free to take guesses here, although I won't confirm or deny until it's time for a writeup) ;)
 
You can bet there are not enough CPU cycles left for any game logic.

Also, the CGA port of the game didn't look that bad. They made good use of the colors.
The per-frame code really doesn't take all that much CPU time - IIRC no more than ~20% in this version ("profiled" using border-color changes). Should be plenty left for game logic, but the real problem would be all the writing to video RAM, which has to fit in vertical blanking for a 'snowless' display. Combined with the scrolling I don't think it'll handle more than 2 additional sprites of a respectable size. I'd like to make it slightly more interesting in the planned final version, so we'll see.

The Marble Madness IBM port doesn't look all that bad on CGA, but it doesn't play well at all at 4.77 MHz. The screen is only updated every 8th frame...
 
Just got a chance to see the demo in action. I downloaded it Saturday but didnt try till just now. Good thing I D/L it Sat as today the link wouldnt work for me. Dunno. Truly incredible Demo. You guys do great work keep it up!

And maybe its me the but initial chip tune music that plays after the initial Text/color portion in the beginning sounds very similar to Life of a pixel. I know I have spent a ton of hours playing that game. Im not saying anyone stole the music, It just sounds similar and my ear caught it.
Glad you liked it!

Ha- never heard of that game until now, but apparently there's a 'Super Life of Pixel' now which includes a "CGA"-styled world...
 
Glad you liked it!

Ha- never heard of that game until now, but apparently there's a 'Super Life of Pixel' now which includes a "CGA"-styled world...
Yes those of us that bought the first release got the updated "Super" version free. Its a nice trip down memory lane with graphics and sound from all the vintage computers and consoles. Each "Zone" is themed after the aforementioned equipment. Worth downloading the demo at least.

Again Beautiful Demo! I had to remove my 8bit VGA card to install a CGA card to view it but it was definitely worth it. I think that pushed Text mode graphics further than anyone ever has before 👍 🍸
 
I think Area 5150 will partially run with 512kB but (from memory) it'll stop rather than skip parts when it runs out. I'm not sure how much of the demo you'll be able to see - it may depend on how much memory the version of DOS you use takes up.

For grins, I ran it in such a configuration (512K, assuming 30K used for DOS), and it doesn't start. We preload and decompress as much as we can right at the start.
For a "544K" configuration if someone has a Rev 0 or 1 BIOS, assuming ~514K free, the demo starts, but ends about 3 minutes in, just after displaying the Shrine picture.

EMS an option?

LOL, no. I mean, sure, I could add it, but if you can add an EMS board to your system, surely you can add either a hard drive or 640K, which would allow the demo to run.
 
You can bet there are not enough CPU cycles left for any game logic.

That is not true for all the effects in the demo. Viler already mentioned a few that only take up 20% CPU, and the real tragedy are all the hoops Viler and reenigne had to jump through avoiding CGA snow. If we happily don't care about CGA snow (like Paku Paku does), then even more time is available, although it seems a shame to limit such a game to clone CGA cards.

And considering 99% of XT-class action games don't run at 60fps, there's even more time available at a more "acceptable" 30fps.
 
*IBM PC 5150 Rev.0 (04/24/1981) BIOS
*IBM PC 5150 Rev.1 (10/19.1981) BIOS
if someone has a Rev 0 or 1 BIOS
I don't think that people should be referring to the IBM 5150's BIOS' as rev 0 and rev 1 and rev 2. It's just going to cause confusion. For example, in another thread, someone may refer to the "rev 1" BIOS, and a reader interpret the "1" as the first BIOS. I think that we should only use '04/24/81' and '10/19/81' and '10/27/82'.
 
A game that keeps smooth scrolling at 60fps (60 frames) on XT (4.77MHz) reminds me of "Battlestorm" by Titus as far as I know.
However, this is also when running in EGA / VGA graphics, not CGA, and when running CGA, 60 frames did not come out.
Even when running in EGA/VGA, there is a slight stutter at 4.77MHz as the number of characters increases.
(Although there is no stutter at 8088 8MHz)
 
Was that in question? 8088MPH ran well on it too.
Most parts are expected to run well enough on clones, but sections like the end credits are more sensitive to inaccuracies than anything in 8088 MPH was. Some later clones (chiefly ones based on custom chipsets) are already known to have issues. Compaq's are some of the most compatible out there, but it's good to have confirmation.
 
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