JamesD

And if a Coco 3 in an FPGA weren't enough... here is the source for the Amiga in an FPGA! http://home.hetnet.nl/~weeren001/

Well, just look at the history of 8 bit machines. Kits for hobbyists where you have to buy a piece here or there and build stuff yourself. TRS-80 Model I, Apple II and Pet ready to use but made with standard chips... lots of chips. More machines follow. Atari 400/800 integrate functionality and adds improved graphics and sound by borrowing from arcade development. A handfull of machine based on parts designed for arcade machines are introduced (Ti-99/4, Vic 20...) A lot of machines based on standard integrated parts are introduced. Updated versions of older models are introduced. Machines based on more advanced customized chips are introduced. And the most amazing part of all that is each advance and wave of new machines is only a year or so apart from each other. Power increases, costs decrease, sales increase... What was once a geek hobby thing starts looking like something for every home or business.

Cool... I guess sometimes when you kick a horse it gets up and walks. Well, it shouldn't be too difficult to implement bank switching. It will just take a little time. Too bad I don't have a 5200.

http://apple2history.org/history/ah06.html "The Revision 0 board had only four colors (green, violet, black, white), but Wozniak had learned that by making a simple alteration he could get two more colors (blue and orange) and two more varieties of black and white. The Revision 1 and later boards were capable of displaying all eight colors." And if you hook up a monochrome monitor and color monitor to older IIs and draw to the hi-res graphics screen in basic you will see colors appear as dot patterns on the monochrome display. You can see games like Space Eggs actually take advantage of this by shifting the sprite left or right by individual bits... which causes the color of the sprites to change color as they fly around the screen. But where there are multiple set bits side by side to form white, the color stays white. You will also notice a slight shift in the position of the pixels in relation to each other where they are different colors even though they should be right on top of each other. Also, check out the photo of the screen drawn with just lines on the page I linked to above. The colors are artifacts. Double hi-res (IIe/c) added red but the mode wasn't on older machines. You seem to have ignored the part of my post that said "Let's face it... if you pick and choose you can make any 8 bit look bad." BTW, just announced last night... someone has created a CoCo 3 in an FPGA. http://www.geocities.com/gary_L_becker/coco3fpga.html

Actually it is you dismissing the advantages of the C64 version as minor.9 Both sides are dismissing the other machine's strong points and trying say the weak points of their machine aren't a big deal. The slower CPU speed of the C64 and the limitations of Player Missile Graphics are just a couple things that come to mind. What have you been smoking? On the only comparable screen (1st level shot) only the hand and the fly are hires vs multicolor, and the hand is 1 color multicolor resolution on atari vs 1 color hires on C64. Now what's better. Apart from this, both games are all multicolor everywhere. Btw, the colors on both screenshots do not reflect the colors of the real machines, so don't use that excuse to push the A8 version. Ok... first of all... the emulator totally missed the C64 palette by a mile and it looks really drab. At least the Atari colors are close. That alone would bias any screen shot comparison. After that the differences appear minor. The game logic was already complete when the author made the Atari version and he could have spent time tweaking things for better game play on the Atari. The additional colors of the Atari version appear to be mostly in the score area although a couple sprites appear to be multi-color. That doesn't mean the C64 couldn't have done the same with the sprites. If you pick and choose, you can find stuff that is better on one machine than the other no matter which you support. In this case I give the edge to Atari but on another game I might go the other way.

Let's face it... if you pick and choose you can make any 8 bit look bad. For example: Hmmm... high quality says the Apple II fan. Apple II's... no color text... unless you used graphics... which were a memory mapped nightmare. And text is a rainbow mess in hi-res or you have to use a very large font that is then barely readable on a monochrome monitor because its a dot pattern. And as for color... red? What's that? We just use NTSC artifacting and it can't generate red. And sound... bzzzzz click click click bzzzzzaaaaaat... unless you buy a card costing more than the other machines and not all games would use it. Speed? 1MHz... not exactly best in class. Hardware sprites? Who needs em when you have a crappy display that eats CPU cycles for breakfast when you try to display arcade graphics. The commands on the C64 are oh so weird... kinda like PR#6 or CALL -151? (I believe those were Apple) And it was all carried forward until the IIgs which finally had a decent graphics memory map in the new modes and added decent sound... too bad they didn't bother adding sprites or a CPU fast enough to keep up with anything else of the day... but hey... it still cost more. Oh... and how could I possibly forget the Apple III which gets hot and spits out it's chips! If it stops working... DROP IT!!!!!! You mean that kind of quality? See what I mean? All of that stuff may be true but I loved the Apple II series and I think they were great machines. I spent almost as much time programming my friend's Apple II+ in high school as I did my CoCo... up until I bought a disk drive anyway. My 8 bit computer collection includes more Apple II type machines than any other 8 bit. 1 Apple II+, 1 Apple IIe, 2 Apple IIc Pluses, 1 Apple IIgs, 1 Laser 128, 1 Franklin Ace 1000 and 1 Apple III. I love the IIgs. There really wasn't anything low quality about the C64. It was just a later design that took advantage of a higher level of integration. Later Atari's did the same. There were crap games for both machines (ok... all machines) and there were great games for both. If you pick and choose you can find games that were great on one machine but not the other no matter which is your favorite. BTW, if you had a C64 you probably had a fastload cart... most of which also had a "DOS Wedge" that had simplified drive commands.

Actually, now that I think about it... it had an 8 bit register arranged like that. I don't know if it was an 8 bit DAC or 6 bit. Either way, they probably could have multiplexed the lines so it could have had an 8 bit DAC output.

It had an 8 bit DAC but 2 bits were used for cassette and 6 for sound. It made making good sounds during action more difficult since you had to keep driving the DAC from an interrupt. The CoCo3 added a programmable interrupt timer that could be used just for that purpose so it was much better for sound. They also had the sound n speech cartridge which even had it's own PIC microcontroller that could drive the sound and speech chip while the cpu did something else. Sadly they priced it too high at first and it didn't sell real well. It did get quite a bit of software support from some companies. It's too bad they didn't make all 8 bits of the DAC available for sound. They could have multiplexed the chip outputs. It would have offered better dynamic range and sound quality. You had to write to all 8 bits anyway so it's not like it would have been slower. There are programs that will play music in 4 part harmony over that lowly DAC and as time went on more and more games did the same. The CoCo3 had a true 16 color modes up to 320x200 as well with palette registers and 64 colors. With artifacting you could easily get hundreds on a TV if you wanted. It was also planned to have a true 256 color mode but it required weird steps to turn it on. Tandy never released the info and destroyed all the Coco stuff when they canceled it so we'll never know if it made it into production machines and how to turn it on if it did. Too bad Tandy drug their feet with the CoCo from day one. If the Coco 3 had come out instead of the CoCo2... it would have been a major player. They still sold millions of the machines. It was Tandy's top seller right up until it was discontinued. The MMU was nice. With OS-9 you could run multiple programs at once with true preemptive multitasking before the Amiga. You could bank the graphics mem in and out of the CPU address space so it didn't take up all your program space. The GIME chip would access it wherever you placed it even if it wasn't loaded in to the CPU address space which makes it a lot more convenient than some of the other setups other systems used. There was even a program that would let you use the additional RAM for BASIC programs. The only other machine that might have been better than the CoCo 3 was the Apple IIgs. It's sound chip was designed by one of the people that designed the SID if I remember right and it was a whole lot better... hands down the best sound chip of any 8 bit machine. It was something strait out of a synthesizer. But then it came years after the other machines. The 65816 isn't quite as good as the 6809 but it did have extended memory addressing built in and higher clock speeds... though the 6309 is even faster than the 6809 and just plugs in place of it. Something like 30% faster at the same clock speed. The IIgs had similar graphics modes to the CoCo 3 but even had a mode where the hardware could have different pallets for different sections of the screen and it was handled in hardware. It allowed many more colors on the screen even though only 16 were used at any location. You could do the same thing on the CoCo but you had to manually change the palette which took clock cycles. For that matter the CoCo I/II could switch color sets on the fly resulting in more colors on a screen than it officially supported. Dragonfire used that trick. Actually, the deluxe joysticks were pretty nice. The tape interface was 1500 baud and worked really well. If your CoCo could handle the double speed poke you could save tapes at about double speed. It took a few pokes to get the machine to read them back in but it did work pretty reliably. A cassette faster than some disk drives... pretty nice. I've been working on a port of a C compiler for it from time to time and I must say that the 6809 supports high level languages and operating systems much better than any other 8 bit CPU of the time. Instead of just page 0 you have a direct page register that lets you access any page in memory with faster instructions. 16 bit pointer registers, multiply instruction, multiple stack pointers, auto increment or decrement... the thing was great. But then you knew that if you programmed it. Some people have been able to drive a lot of sprites with just the CPU but you almost have to convert each sprite to code to reduce the clock cycles if you really want to push things. At 4MHz the thing probably would have been able to keep up with hardware sprites but sadly, they never came out with a model based on one of the faster 6809s. I think there were some available that could handle 8MHz. Well... there were versions of almost every arcade game but they weren't licensed versions. Tandy was clearly to blame for a lot of that since they barely supported the machine. It wasn't until later in the CoCo's life that Tandy offered a program where you could order a lot of aftermarket software through your local Radio Shack. Otherwise it was pick up a magazine and order it. Radio Shack actually pulled additional sound support and the 256 color mode from the CoCo3 so it wouldn't interfere with 1000 sales. I switched to the Amiga instead of the Coco3 and didn't buy one till years later. Looking back I wish I had gotten a CoCo3 when they first came out.

Touching as many subtopics as I can stand in a single post. Reguarding the slow C64 drive discussion... The slow C64 disk drive issue goes all the way back to the Vic20. The chip in the Vic20 which would have allowed fast transfers (6522) was buggy and it wasn't detected until production of the chip had already started. So they just made it a slow software driven bit banger interface. The C64 had fixed hardware (6526) but for compatibility with the Vic20 drive, didn't use it. A marketing decision. And, because the processor in the C64 is turned off for 40 microseconds every 512 microseconds, it kept missing the interrupt signals that control the disk interface. The solution: slow the drive down even further. Boggles the mind doesn't it? They weren't allowed to make it faster but it was ok to make it slower. Attaching a couple wires between the port and serial chip along with a driver allow the C64 to use the C128 burst mode that was available on later drives. That mode was supposed to be available on the Vic20 from the beginning btw. http://www.cs.tut.fi/~albert/Dev/burst/ As for Atari VS C64... The C64 had a better sound chip technically speaking but it was used to the point of annoyance in a lot of games. It definitely had better sprite hardware and better graphics in SOME ways. The Atari had more colors, a faster clock speed and 4 voice sound. And Atari licensed a lot of arcade games which lead to a lot of titles for it. The serial bus was also pretty advanced for it's day. To be honest neither machine is drastically superior to the other and depending on what you were doing either could be the better choice. This also applies to other machines as well. The Speccy had a pretty decent clock speed among Z80 machines and due to the way it's display works you could drive graphics to it pretty fast. It probably has the largest library of 3D or isometric games of all the 8 bits. The Plus/4 makes up for the lack of sprites and a SID with with fast speed, more memory and more colors. I've seen some of the best looking 8 bit graphics out there on this "loser" of a machine. It also offered an excellent BASIC with more available RAM for BASIC programmers out of the box than any other 8 bit system. It definitely looks cooler than a breadbox C64. The Tandy CoCo had the best 8 bit CPU and the artifact graphics of the older models were used to do some amazing things from a 2 color mode... unless you didn't have an NTSC machine and then it was pretty blah. Extended Color Basic was the best built in BASIC of the day which is why I got one. The CoCo 3 is nothing short of amazing in the hands of a great programmer. The new Donkey Kong game is by far the best version for an 8 bit. But then the author does work on video games for a living and had access to the original source apperently. The Apple II display was a total hack but they made it work. It had a decent BASIC, one of the nicest boxes and floppies were common. Games were everywhere. With it's expandability and some marketing guaranteed it a solid place in the industry. 80 column text and floppies made it a hit with businesses. The TRS-80 Model I beat the Apple II to market and evolved into the Model III/IV machines which were a hit with businesses. Game wise... there was some cool stuff in spite of it's limitations. The Atari Star Trek game discussed elsewhere on these forums grew out of a Model I game. In reguards to the Amiga discussion... Atari funded them at some point but Jay Miner was NOT an Atari employee at that point. The Amiga was neither an Atari or Commodore. Atari had no exclusive and did not direct the design of the machine. They should have asked for first right to purchase the technology in their financial agreement but they didn't and Commodore swept in with an offer and bought the technology. If anything the Amiga was a product of Jay Miner but Jay = employee... not Atari and not Commodore. As a person that used to sell Amiga machines I can tell you that we always talked about Amiga like it was a different company than Commodore.

I haven't kicked the dead horse in a while so... any progress?

I ran across a Star Trek game web page that had a fairly complete history of the game a few years ago but I don't know if it's still around. Lance Micklus had one of the best if not the best variation on the theme IMHO. I first played it on the TRS-80 Model I (first published in Softside Magazine if I remember right) and later versions got better and better. I think his last port was for the Tandy CoCo which he claimed was the best version. I had a Coco and to this day I've never played the coco version.

Looks good - not sure if its possible to add a bit of texture to the side walls - understand you are looking from above but maybe a small pattern to give it a rocky look. Texture? I don't think I'd use that term with any 8 bit games. The original Gauntlet had a mix of different dungeons. Some were brick others were rock or whatever. I don't see any problem with at least some of the walls looking like that. Oops... I meant Diablo. Gauntlet did have different wall types but lacked the depth of gameplay. Building characters, variety of enemies and such are much better on modern role playing/shoot em ups. There's nothing wrong with making an entirely different game that borrows the best features of these games.

Looks good - not sure if its possible to add a bit of texture to the side walls - understand you are looking from above but maybe a small pattern to give it a rocky look. Texture? I don't think I'd use that term with any 8 bit games. The original Gauntlet had a mix of different dungeons. Some were brick others were rock or whatever. I don't see any problem with at least some of the walls looking like that.

I picked up a couple 128MB cards cheap a few years ago and still use them. Now you can get 1GB for about 1/3 the price.

Wow, I managed a thanks? Guess I should help more and earn my keep.

The PC game 'Clive Barker's Undying'. I paid $10 for it and 'American McGees Alice' at Walmart. I expected both to be turkeys given the price and the fact I'd never heard of either one. Both were good, especially Undying. Sadly it still has a couple bugs so if you ever play it, save your place regularly just to be safe.

The coco was Tandy's top selling computer for a long time as it was. I don't know how many were sold but it was likely in the millions (just look at the number on ebay). If Tandy hadn't dumped the Coco line it would have continued to be there top seller for a while. I think Tandy wanted buyers to become fans of their PC line rather than the Coco. Tandy *supposedly* had a Coco4 in the works that was going to be an all in one system with a built in drive similar to some of their PC line. I'm not sure if that is true or not since I've never heard of a prototype surfacing. But then Tandy pretty much destroyed everything Coco when the line was canceled. I think someone wanted to make sure it was never brought back to life again. BTW, that Donkey Kong game may not have been possible back in the day since people were rarely given access to the original source when creating a licensed version.

It could probably be done without the GAL.

I've tried the output of about every old computer I have with my Magnavox 15" LCD TV/Monitor and there isn't much that works. However, I've seen the same monitor working great with an RGB to VGA converter box on a Tandy Coco3. I don't know if the box will work with an Atari without mods but the picture was beautiful.

That is undeniably true, but it misses the point. You could make that argument about any number of things. For the general case, though, I don't consider floats a good utility/performance tradeoff in an 8bit compiler. No it doesn't. What you say is true but you still can't take a program and port it from one machine to the next without creating some sort of custom library for every machine you want it to run on and existing software will need to be rewritten to port it. You can actually use whatever decimal representation you want behind the scenes and the compiler could use it as a float library without software knowing the difference unless it requires more significant digits than your math lib.

They were more worried that it was competing with their own machines. The coco was their top seller right until the end of it's production. Impressive.

Keep in mind that is an unfinished version and with some additional work it might have been faster. With some optimizations for the 6309 it would definitely be faster. Yeah, it was a cool game for it's day. Someone at Tandy must have really disliked the Coco to cancel everything the way they did. I'm guessing someone from the PC projects got into higher management but that may not be true.

Here are screenshots and a video from the actual game. It seems Tandy canceled it and several other games for the Coco3 that were near completion. Alternate Reality: The City(?) was supposedly another title this happened too. Link

More screenshots http://www.lcurtisboyle.com/nitros9/donkeykong.html

And there are some Dragon games running on the Coco now. Link