Atari v Commodore

[atariksi]

I'm sorry - but where is your proof that I thought wrong? The clocking is the same as required for the high res case and the internal circuitry is actually smaller - rather than 4 16 bit shiftregisters and 4 16bit latches ( for the ST case ) I can implement a similar system with 1 16 bit latch and as little as 20 bits of shift register..

 

The EGA system used a planar architecture in part to allow faster programming (though the usefulness of those features was limited until the VGA added a couple of practical enhancements). For certain applications, the planar design is very nice; for others, it's a pain in the tush. Nobody uses those modes any more, but for some purposes they worked quite well.

 

As for hardware complexity or simplicity, planar modes make it easy to support an arbitrarily-variable number of bits per pixel. Using two or four bits per pixel may be more convenient in a "chunky" system than in a planar one, but what about using three or five? A bit-plane architecture which is equipped to handle pixel-level shifting of two sets of bit planes may use the two sets individually to produce an parallax-scrolling background, or together to produce more colors.

 

Unless one is using byte-sized "chunky" pixels, I don't see a huge difference between planar and chunky approaches for most applications.

 

BTW, I wonder what machines have used interesting addressing tricks to allow a processor to view memory in different formats? Rescue on Fractalus on the 7800 omitted an address line from its RAM chip, so as to allow each byte of RAM to be displayed twice, but what other tricks have been done?

 

I had an EGA card w/64K RAM and it could only do 640*350*4 colors but then you pop in an extra 64K and it did 640*350*16 colors so that's one advantage of using planar modes. And it didn't slow down the system anymore to have those extra two planes nor did the clocking change to the i/o ports to do that mode.

[Crazyace]

Weren't some of the EGA design decisions related to the fact that there was only 64k of memory visible to the host - ( It's been a very long time since I looked at any EGA/VGA programming )

I remember the write expansion being quite nice ( host writes to single bitplane - EGA writes value to multiple bitplanes )

[atariksi]

You need higher clocking for chunky rather than using planes which get read in parallel.

 

No. You don't. This is the source of much of your confusion.

...

List all my confusions and then I'll answer you otherwise it's Chewbacca defense.

I just did. You think you need higher clocking to read the same amount of data once the bits are in a different order.

 

What takes more bandwidth to read? A 32K screen or a 32K screen? You seem to think that planes are some sort of compression scheme. You are therefore confused.

 

Okay, so you only had one in mind but you make it sound like "much of your confusion" as if it already existed.

 

Planes have their advantages. I don't think they are a compression scheme-- that's your speculation. I have seen implementations where the bandwidth is lower with planes vs. chunky modes.

[frogstar_robot]

you will find pitting atari against commodore has a way of going on and on, it's the secret to the never ending thread! la laaa laaaaa la la la laa laaaaa never ending thread!! la laaa laaaaa la la la laa laaaaa (beware the nothing!)

 

The best thing to do is to never close the thread. After all, two or three months down the road someone will innocently ask something like "Which games were superior on the C-64 and on the A8?" Rather than pointing them at this thread, it starts aaaaaaaaaaalllllll over again.

 

The C-64 can sometimes do better scrolling, has more sprites, can easily do a 320x200 16 color screen, with cleverness can do screens with more apperant colors, often has more flexibility for charmode screens, has a sound chip that that very like a early analog synth and is thus very plastic for music and has some VERY good sidescrollers to it's name.

 

I have no problem giving the 64 those points and some others I no doubt left out. I still like the A8's particular bag of strengths and weaknesses better. So neyyyuhhhhh!

[Bryan]

Planes have their advantages. I don't think they are a compression scheme-- that's your speculation. I have seen implementations where the bandwidth is lower with planes vs. chunky modes.

 

I don't know about your EGA card, but I do know what happens on modern graphics cards. There are many levels of graphics card in a particular series and there are two main factors that affect performance. One is the bus clock. When you spend more you usually get faster RAM. The other is bus size. Better cards have more parallel bits going into the chip so more data is read per clock cycle.

 

Your EGA card may well have had a bus split between the two banks of RAM. If you only had one bank, you may have been using a smaller bus.

 

You cannot, however, create bandwidth by rearranging the data (either that, or I'm going to get my DSL provider to send all my data as planes!).

[atariksi]

Ok, some one list some specs:

 

Number of sprites per scanline (hardware and lowest color count - i.e not pairing)?

Number of sprites per screen?

If the total number of sprites can be extended (by changing the registers on the fly), what's the CPU resource ratio?

What res are the sprites available in?

Can you mixed hi-res and low-res sprites, and can you mix them with a different background res?

How many colors per sprite (both for pairing or non pairing)?

Native/max sprite sizes?

 

In the past 100 or so posts, we just discussed most of the above. Atari is always going to win when it comes to extending the sprites via replication-- it can set all sprite data base via a single register and it's sprites are full screen height so you only have to worry about HPOS setting. C64 has the higher resolution sprites (horizontally) and more horizontal coverage by default w/o any CPU tricks-- 24*21 in monochrome or 12*21 in 3 color mode. Resolution in Y direction is the same for both. Atari has 4 players and 4 missiles while C64 has 8 players called sprites (not 7-up).

 

Total number of sprites per screen, Atari wins since you can have thousands of 8*1 sprites flooding the entire screen including overscan using less cycles since it's sprites are 8*248 and missiles are 2*248. Once you get into overscan screen modes, Atari gets more of an advantage. You can read more if you skim through previous few pages...

[atariksi]

Weren't some of the EGA design decisions related to the fact that there was only 64k of memory visible to the host - ( It's been a very long time since I looked at any EGA/VGA programming )

I remember the write expansion being quite nice ( host writes to single bitplane - EGA writes value to multiple bitplanes )

 

Yeah, they are still emulated with standard VGA cards. Some also supported a rotate, xor, or other logical function while you wrote to all four bitplanes at the same time using A000:0000.

[atariksi]

Planes have their advantages. I don't think they are a compression scheme-- that's your speculation. I have seen implementations where the bandwidth is lower with planes vs. chunky modes.

 

I don't know about your EGA card, but I do know what happens on modern graphics cards. There are many levels of graphics card in a particular series and there are two main factors that affect performance. One is the bus clock. When you spend more you usually get faster RAM. The other is bus size. Better cards have more parallel bits going into the chip so more data is read per clock cycle.

 

Your EGA card may well have had a bus split between the two banks of RAM. If you only had one bank, you may have been using a smaller bus.

 

You cannot, however, create bandwidth by rearranging the data (either that, or I'm going to get my DSL provider to send all my data as planes!).

 

Actually, the EGA card had 32K base that gives 640*350*2 colors and it was a brand name (Paradise) and you can incrementally install 32K to get more and more planes without increasing clocking. It was the norm back those days EGA w/less than 64K so it's not some special EGA card. On the other hand, I had this VGA card with 256K expandable to 512K that would not do 640*480*256 mode until I installed another 256K but even after you install the memory the clocking had to be sped up because it was a chunky set up. So don't tell me it's always the same bandwidth/clocking. Yeah, you cannot rearrange the data to create bandwidth (obviously) but if your circuit is set up to handle multiple bitplanes, planar is superior.

 

It's nothing to do with serial buses (DSL)-- that was a joke I guess.

[HiassofT]

either that, or I'm going to get my DSL provider to send all my data as planes!.

Not as planes, but via planes :-)

 

Just remember what Andrew S. Tanenbaum wrote: "Never underestimate the bandwidth of a station wagon full of tapes hurtling down the highway."

 

Now think about the bandwidth of a large bunch of Boings or Airbusses loaded with harddrives would be.

 

Just be sure you live near the airport, otherwise your data has to travel the last miles using a slow bus :-)

 

SCNR,

 

Hias

[Keatah]

I'm just posting to post to what seems to be the longest thread of atariage! Carry on..

[atariksi]

you will find pitting atari against commodore has a way of going on and on, it's the secret to the never ending thread! la laaa laaaaa la la la laa laaaaa never ending thread!! la laaa laaaaa la la la laa laaaaa (beware the nothing!)

 

The best thing to do is to never close the thread. After all, two or three months down the road someone will innocently ask something like "Which games were superior on the C-64 and on the A8?" Rather than pointing them at this thread, it starts aaaaaaaaaaalllllll over again.

 

The C-64 can sometimes do better scrolling, has more sprites, can easily do a 320x200 16 color screen, with cleverness can do screens with more apperant colors, often has more flexibility for charmode screens, has a sound chip that that very like a early analog synth and is thus very plastic for music and has some VERY good sidescrollers to it's name.

 

I have no problem giving the 64 those points and some others I no doubt left out. I still like the A8's particular bag of strengths and weaknesses better. So neyyyuhhhhh!

 

You exaggerated on some points-- C64 does not have a 320*200*16 color screen-- even their 160*200 does 16 colors with restrictions. I can also do a 160*200*16 screen on Atari (ANTIC mode K) w/restrictions. You can have more sprites on Atari but the trend on C64 software is to use more and more sprites since that's their best graphical elements. Even where they squeeze more colors in-- you still run into shading issues since those are hardly ever a choice.

[potatohead]

The C-64 can sometimes do better scrolling, has more sprites, can easily do a 320x200 16 color screen, with cleverness can do screens with more apperant colors, often has more flexibility for charmode screens, has a sound chip that that very like a early analog synth and is thus very plastic for music and has some VERY good sidescrollers to it's name.

 

Neither do I. Those are actually rational, solid points. It is a nice 8 bit machine, after all.

 

...it's just no Atari

[frogstar_robot]

You exaggerated on some points-- C64 does not have a 320*200*16 color screen-- even their 160*200 does 16 colors with restrictions. I can also do a 160*200*16 screen on Atari (ANTIC mode K) w/restrictions. You can have more sprites on Atari but the trend on C64 software is to use more and more sprites since that's their best graphical elements. Even where they squeeze more colors in-- you still run into shading issues since those are hardly ever a choice.

 

Well perhaps not "easily" and not strict 320x200x16 screens but good results are nonetheless possible with the VIC-II and a C-64 CAN build 16 color 320x200 screens with a mix of liberties and restrictions that isn't open to the A8. A C64 can achieve a fine grained screen with less apparent effort than an A8 can. And what I said about "apparent" colors is not to be neglected. As much as I hate to defend Commies here, it isn't going to kill you to admit that a C-64 can do some amazing things in the right hands:

 

http://www.cascade64.de/csc_graphics.php

http://www.studiostyle.sk/dmagic/gallery/gfxmodes.htm

[+Stephen]

Well perhaps not "easily" and not strict 320x200x16 screens but good results are nonetheless possible with the VIC-II and a C-64 CAN build 16 color 320x200 screens with a mix of liberties and restrictions that isn't open to the A8. A C64 can achieve a fine grained screen with less apparent effort than an A8 can. And what I said about "apparent" colors is not to be neglected. As much as I hate to defend Commies here, it isn't going to kill you to admit that a C-64 can do some amazing things in the right hands:

 

http://www.cascade64.de/csc_graphics.php

http://www.studiostyle.sk/dmagic/gallery/gfxmodes.htm

Yeah - IFLI mode looks incredible. It seems to be their version of our HIP mode (higher res of course).

 

Stephen Anderson

[atariksi]

You exaggerated on some points-- C64 does not have a 320*200*16 color screen-- even their 160*200 does 16 colors with restrictions. I can also do a 160*200*16 screen on Atari (ANTIC mode K) w/restrictions. You can have more sprites on Atari but the trend on C64 software is to use more and more sprites since that's their best graphical elements. Even where they squeeze more colors in-- you still run into shading issues since those are hardly ever a choice.

 

Well perhaps not "easily" and not strict 320x200x16 screens but good results are nonetheless possible with the VIC-II and a C-64 CAN build 16 color 320x200 screens with a mix of liberties and restrictions that isn't open to the A8. A C64 can achieve a fine grained screen with less apparent effort than an A8 can. And what I said about "apparent" colors is not to be neglected. As much as I hate to defend Commies here, it isn't going to kill you to admit that a C-64 can do some amazing things in the right hands:

 

http://www.cascade64.de/csc_graphics.php

http://www.studiostyle.sk/dmagic/gallery/gfxmodes.htm

 

I am more interested in the truth than making Atari win or Commodore win. There no 320*200*16 mode in the real sense of 4-bit depth. Interlaced modes cannot be compared to 50/60Hz modes. Once you open up interlaced, Atari expands its palette and modes much more so and lesser flicker due to more shading. So to keep comparing apples to apples, compare 50/60Hz modes with 50/60Hz modes. A real 4-bit depth screen would be like GTIA modes 80*200*16 (or 96*240*16 overscanned). Now by playing with char height and sprites, you can get some more colors on C64, but then you have to apply Atari sprite overlays, GPRIOR, etc. as well to its existing repertoire of modes.

[atariksi]

The C-64 can sometimes do better scrolling, has more sprites, can easily do a 320x200 16 color screen, with cleverness can do screens with more apperant colors, often has more flexibility for charmode screens, has a sound chip that that very like a early analog synth and is thus very plastic for music and has some VERY good sidescrollers to it's name.

 

Neither do I. Those are actually rational, solid points. It is a nice 8 bit machine, after all.

 

...it's just no Atari

 

I don't see how "more apparent colors" is a rational statement. More apparent colors than what? You only get more than 16 colors if you use interlace and if you employ interlace on Atari, you get many more combinations.

[Heaven/TQA]

Ok, some one list some specs:

 

Number of sprites per scanline (hardware and lowest color count - i.e not pairing)?

Number of sprites per screen?

If the total number of sprites can be extended (by changing the registers on the fly), what's the CPU resource ratio?

What res are the sprites available in?

Can you mixed hi-res and low-res sprites, and can you mix them with a different background res?

How many colors per sprite (both for pairing or non pairing)?

Native/max sprite sizes?

 

In the past 100 or so posts, we just discussed most of the above. Atari is always going to win when it comes to extending the sprites via replication-- it can set all sprite data base via a single register and it's sprites are full screen height so you only have to worry about HPOS setting. C64 has the higher resolution sprites (horizontally) and more horizontal coverage by default w/o any CPU tricks-- 24*21 in monochrome or 12*21 in 3 color mode. Resolution in Y direction is the same for both. Atari has 4 players and 4 missiles while C64 has 8 players called sprites (not 7-up).

 

Total number of sprites per screen, Atari wins since you can have thousands of 8*1 sprites flooding the entire screen including overscan using less cycles since it's sprites are 8*248 and missiles are 2*248. Once you get into overscan screen modes, Atari gets more of an advantage. You can read more if you skim through previous few pages...

 

thousands??? now we are calling every scanline of a player stripe a sprite? come on... and of course our superfast cpu can move around "thousands" of sprites in 50/60 frames... i have done this several times in more than 20 years... called "stafield" effect...

[emkay]

Yeah - IFLI mode looks incredible. It seems to be their version of our HIP mode (higher res of course).

 

 

If we learn to fulfill complete sentences, the upper one could be written as:

 

Yeah - IFLI mode looks incredible. It seems to be their version of our HIP mode (higher res of course but less colours).

 

 

But. IFLI is interlace. It means that the shown picture is not what the hardware produces for real.

With interlace you could do 256 colours in hires on the A8...

Edited April 8, 2009 by emkay

[emkay]

thousands??? now we are calling every scanline of a player stripe a sprite? come on... and of course our superfast cpu can move around "thousands" of sprites in 50/60 frames... i have done this several times in more than 20 years... called "stafield" effect...

 

Reduce this technique to a common attack wave and you have at least tenths of "sprites" on the screen, as needed for a good scrolling game...

The Atari offers so much to ease up game programming . But at the end only some guy like Archer McLean handled the moving objects correctly.

I bet, if he'd gone further with coding on the A8, you'd have seen a "Dropzone" with full parallax scrolling later...

[Allas]

i like those TIP pictures with lot of colors.

 

[Bryan]

So don't tell me it's always the same bandwidth/clocking.

 

Well, you can't tell me why the clocking should be different- just that you believe it to be so. Let's see a cycle by cycle breakdown of what happens on the bus and where the savings are. I am an electronic engineer by trade and have never encountered this planar clocking advantage.

 

Planar data doesn't make the ST read data any faster and it doesn't make the Amiga read data any faster (after all, we can calculate the size of the screen and the cycles used and it all adds up as it should), but apparently it makes old PC cards defy physics.

 

Yeah, you cannot rearrange the data to create bandwidth (obviously) but if your circuit is set up to handle multiple bitplanes, planar is superior.

 

If your circuit is set up to handle planar, then the only difference is how you program for it. There are some software tricks that are more easily done on planar data and there are many things that are easier with chunky data. That's the only performance difference you will ever see.

 

Anyway, until you present me with a technical description of clocking for chunky vs. planar, I am done with this discussion.

Edited April 8, 2009 by Bryan

[frogstar_robot]

I don't see how "more apparent colors" is a rational statement. More apparent colors than what? You only get more than 16 colors if you use interlace and if you employ interlace on Atari, you get many more combinations.

 

I provided two links that show it is rational. Yes the C64 can only output 16 actual colors from it's hardware and yes PAL and NTSC quirks and page flipping can be used to generate the appearance of more colors than that. And yes I know that if versions of those techniques are employed on an A8 then the apparent color depth goes up past anything a C64 will be able to do.

 

Nonetheless without extensive register diddling, the A8 320x200 screen has count 'em two colors. This color resolution can be vastly increased vertically but one still only has two colors per scanline. Tricks to get it up horizontally are at least as onerous as the C-64 restrictions on their modes if not more so. Indeed, software mode 320x200 pix (C8 mode say) aren't terribly common.

 

I think my original point fully valid: The C64 can do some amazing things in the right hands and it won't kill us to admit it. And I've already said that I prefer A8s over Commodores but that isn't a need to ensure the A8 must be the winner of every possible comparison.

 

I think making ANY of these old 8-bits exceed what their original designers thought possible is very very cool.

[irwin]

i like those TIP pictures with lot of colors.

Atari: 160x119 - 256 colors - interlace

but

I find this:

C64: 320x200 - 16 colors and dithering - and no interlace!

or

C64: 296x200 - 16 colors and dithering - interlace

[R6502A]

I think my original point fully valid: The C64 can do some amazing things in the right hands and it won't kill us to admit it. And I've already said that I prefer A8s over Commodores but that isn't a need to ensure the A8 must be the winner of every possible comparison.

 

 

The same is true of the Atari 8 bit. In the right hands some amazing things can be achieved with the amazingly flexible hardware of the Atari 8 bit. It is just that back in the day, more often than not, the Atari was in the hands of lazy?/time/cost constrained developers content only to use the Atari's vanilla setup and code for the lowest common denominator 16k machine.

[Allas]

Atari: 160x119 - 256 colors - interlace

but

I find this:

C64: 320x200 - 16 colors and dithering - and no interlace!

or

C64: 296x200 - 16 colors and dithering - interlace

 

 

Looks great, I've never seen before. But 1st image haven't 16 colors, maybe you can send the exact C64 pictures, or better send a link to the executable to view on the real C64.