Anyone looked into porting Sega Genesis games?

[doctorclu]

So anyone looked into porting Sega Genesis games to the Jaguar? What steps would a person need to do to bridge the two? (Looking to see if anyone has researched this yet).

 

Thanks!

 

Doctor Clu

[justclaws]

Hello Doc,

 

So anyone looked into porting Sega Genesis games to the Jaguar?  What steps would a person need to do to bridge the two?  (Looking to see if anyone has researched this yet).

I looked into the Sega Genesis/Megadrive home-brew scene a while

back, thinking maybe there was something I could learn or use from

there, but unless I just failed to find the good stuff, there isn't much

going on there, and they lack so much information compared to the

Jaguar (which with Sega still around, make sense, sadly, although it

might seem the opposite should be true to some people....) and so

there was nothing to do. Interesting little community of hackers...

 

With regard to actually porting binaries, that looks just too impossible

once again, as is the case with most binary ports. The Jaguar would

need to run an emulation layer of some sort, to pick up writes to the

Megadrive addresses, and remap them onto a "hardware emulation

layer" running on the GPU or DSP perhaps. However, they would be

needed in any case to emulate the Megadrive custom chips, and it

is impossible anyway, because the 68000 has no support for memory

protection of the sort necessary to trap these writes to such addresses.

 

Now if somebody had source, that might be more possible, but then

we are back to the age-old problem of somebody having the time

and interest to rewrite lots of code to port a (probably 2nd-rate)

game from Megadrive to Jaguar, avoiding any legal hassles, and an

artist who could upgrade the 4-bit graphics to at least 8-bit to look

better I guess on the Jaguar. (Not that I would object to playing a

Megadrive game intact on the Jaguar... as I would any new games!)

 

Anyway... sorry for the long slightly rambling post on the subject,

but I'm just "thinking on the fly", so you've got a minor brain dump,

and that is bound to be a bit ragged with all the things going on here!

 

Cheers, and regards,

JustClaws,

[doctorclu]

I believe someone said once that Double Dragon 5 was a port from the Sega 32 or Genesis? Am I correct in that?

 

I also hear of ports from the Amiga, and a few others. To matter the fact, I would love to learn what it took to "port" these from various systems, and what systems have been ported from.

 

Emulation is nice, but the Jag "Dunna have the power cap'tain!" So we need programs changed to work in the Jag.

 

I hear of a lot of games that were pulled from other 68k systems for example. Were these simply ported over, using primarily the 68K, and then told how to display visdeo and changed so the Jag controller would work?

 

Been wondering this for the early Arcade games that used the 68K progrocessor, and there were a few. Wondering what it would take for a little mini-mame that would run those that were run on the 68K.

 

(I think Joust sadly was run on a 68030.)

 

Anyway, thoughts?

[justclaws]

Hello,

 

I believe someone said once that Double Dragon 5 was a port from the Sega 32 or Genesis?  Am I correct in that?

Most likely from the Genesis (Megadrive in Europe). I'm not sure.

 

I also hear of ports from the Amiga, and a few others.  To matter the fact, I would love to learn what it took to "port" these from various systems, and what systems have been ported from.

So would I, it would be nice to hear some stories from developers who worked on porting other system's titles to the Jaguar, but these people seem to be "lost" to the scene, original Jaguar developers, less so. I guess to most developers doing ports, it was purely for the money, and so they didn't dwell on the Jaguar so much, and never really cared about it.

 

I hear of a lot of games that were pulled from other 68k systems for example.  Were these simply ported over, using primarily the 68K, and then told how to display visdeo and changed so the Jag controller would work?

The source code is necessary. Yes, most other systems like the Atari ST, Amiga, PC, they have a frame buffer, and the program writes to that. Thus, it's quite easy to change the source code to write to another address, patch a few sprite blitting routines, and get the sound running, if you already have 68000 source from such a system. It is this sort of thing which allowed several Amiga games to be ported to the Jaguar.

 

Bastian Schick who wrote BJL also wrote code which emulated the Amiga sound system on the DSP, making Amiga sound code more portable, and Nanomonic did something the same as I recall, or maybe another UGD-JAG developer. Also Sinister Developments wrote the excellent MOD player, which allows popular Amiga format music to be played on the Jaguar. (I forget off-hand who did what on the Amiga sound emulation though, they're all Jaguar UnderGround good guys for several years.)

 

Been wondering this for the early Arcade games that used the 68K progrocessor, and there were a few.  Wondering what it would take for a little mini-mame that would run those that were run on the 68K.

I don't believe it helps a lot that they're 68000. The thing is that you need to either modify the code, or have a system which can intercept writes to memory, and cause a trap. This needs memory protection support in the CPU, and this is OK from the 68020 onwards. The 68000 cannot do this. Even with a 68000 it would need code written to emulate the hardware of the old system, it's a subset of any emulator.

 

That's my take anyway, but I'm not an emulator expert, I may be wrong!

 

Regards,

JustClaws.

[justclaws]

Hey Doc,

 

So anyone looked into porting Sega Genesis games to the Jaguar?  What steps would a person need to do to bridge the two?  (Looking to see if anyone has researched this yet).

 

A Jaguar devkit (Alpine or BJL) and one of these perhaps...

http://home.hiwaay.net/~eubanks/SegaDevKit.htm

 

There's also some source code on that site, and on here...

http://www.emulationzone.org/projects/meta...alix/index2.htm

 

Cheers,

JustClaws.

[JAGUAR]

So whats up with this? Seems Genesis ports via 68k wouldn't be hard at all...

[sh3-rg]

So whats up with this? Seems Genesis ports via 68k wouldn't be hard at all...

 

Well you've had 11 years since that post was made, how far have you got?

 

Also, http://atariage.com/forums/topic/175672-1995-e3-2-hours-of-jag/page-2#entry3170406 ?

Edited February 5, 2015 by sh3-rg

[+CyranoJ]

If all these porting things "wouldn'd be hard at all" you'd have figured the ultra active, ossum old skool devs would have done them all by now. After all, there's plenty of source code for them out there.....

 

LOL.

 

Roawr.

 

Edited February 5, 2015 by CyranoJ

[Felyx]

Anyone looked into porting Call of Duty Black Ops or Battlefield 2142 on Jaguar? nothing difficult...

Edited February 5, 2015 by Felyx

[walter_J64bit]

Anyone looked into porting Call of Duty Black Ops or Battlefield 2142 on Jaguar? nothing difficult...

I was wanting halo!

Edited February 5, 2015 by walter_J64bit

[Felyx]

I was wanting halo!

Lucky you: some succeeded to port it already on VCS2600, that is piece of cake to port Halo on Jag

 

Do the math

Edited February 5, 2015 by Felyx

[Rick Dangerous]

I was wanting halo!

 

If the guy who did Halo for the 2600 did Halo for the Jag I would be first in line..

 

I'm guessing the Jag doesn't have the same appeal and nostalgia factor for him though..lol

Edited February 5, 2015 by travistouchdown

[Bill Loguidice]

 

Well you've had 11 years since that post was made, how far have you got?

 

Also, http://atariage.com/forums/topic/175672-1995-e3-2-hours-of-jag/page-2#entry3170406 ?

 

Apparently I made his extensive block list. I'm honored I guess.

[Rick Dangerous]

With Sega gegesis consoles and games being so plentiful and relatively cheap (especially compared to jaguar) doesn't it make sense to just play those games on that system?

 

I mean st games I understand, my local play and trade doesn't have a half dozen of them shrink wrapped on the shelf. Genesis though...not so much.

[+madman]

 

Apparently I made his extensive block list. I'm honored I guess.

I'm pretty sure 95% of the active participants on the Jag forum are on his block list.

[Chilly Willy]

There's a big difference between porting ST games and Genesis games - let's just look at one area: graphics. The ST uses plain 16 color bitmap graphics; the toughest thing about it is that it's in bitplane format rather than chunky format. You can use DMA to change the color palette on every line, if you so desire, but that's not a big deal. There are no sprites to worry about. Now let's look at the Genny - you have two planes of 16 color tiled graphics, with the ability to choose between four sets of color registers with every tile. You have fairly complicated scrolling and priority modes, as well as up to 80 sprites you have to mix into the whole mess. You can change a number of things on the fly - not the entire palette, but a number of color registers, among other things. At least the tile data is in chunky format, but it is otherwise a big pain in the ass. Even emulators on PCs with near infinite speed have fun getting the graphics right.

[+CyranoJ]

No, you can't use DMA to change colors on the fly. Really, do people use the big bumper book of bollocks to get facts about things they don't know around here?

 

Lol ☺

[sh3-rg]

There's a big difference between porting ST games and Genesis games - let's just look at one area: graphics. The ST uses plain 16 color bitmap graphics; the toughest thing about it is that it's in bitplane format rather than chunky format. You can use DMA to change the color palette on every line, if you so desire, but that's not a big deal. There are no sprites to worry about. Now let's look at the Genny - you have two planes of 16 color tiled graphics, with the ability to choose between four sets of color registers with every tile. You have fairly complicated scrolling and priority modes, as well as up to 80 sprites you have to mix into the whole mess. You can change a number of things on the fly - not the entire palette, but a number of color registers, among other things. At least the tile data is in chunky format, but it is otherwise a big pain in the ass. Even emulators on PCs with near infinite speed have fun getting the graphics right.

 

You seem to be confused as to whether you're talking about emulating or porting... because none of that really matters at the end of the day when you're doing a source port, does it? You keep the logic and scrap the rest, make use of the hardware in front of you to recreate the game as you see fit - all the advantages of the target platform's hardware and none of the originating platform's constraints and quirks.

 

If I wanted to take a megadrive game and bring it to Jaguar, I'm not going to be concerned about the way the md handles its sprites and any of the code that places tiles in those two 16/64 colour layers, that's all platform-specific cruft I'm going to junk. Same goes for the ST... I'm not at all concerned about a software sprite routine that pre-shifts or generates what I see on screen. All that gets binned and in its place I have the Jaguar's OP do what it does best in a way that makes sense given the required results on screen.

 

Well, I mean, I'm not... because I'm not a coder... but even I can see that's not how to go about a game source port.

 

Anyway, all completely moot points because of not only what travis says above, but the fact that, from the point of view of whoever is doing it, porting is the dullest and least creative exercise someone could wish to waste away their time with... probably best left to those without an ability for creative expression or understanding of how to build games that work from the ground up, but with a desire to just do something for the sake of doing something. And this is the main reason why not so much actual porting takes place...

Edited February 6, 2015 by sh3-rg

[Chilly Willy]

You seem to be confused as to whether you're talking about emulating or porting... because none of that really matters at the end of the day when you're doing a source port, does it? You keep the logic and scrap the rest, make use of the hardware in front of you to recreate the game as you see fit - all the advantages of the target platform's hardware and none of the originating platform's constraints and quirks.

 

If I wanted to take a megadrive game and bring it to Jaguar, I'm not going to be concerned about the way the md handles its sprites and any of the code that places tiles in those two 16/64 colour layers, that's all platform-specific cruft I'm going to junk. Same goes for the ST... I'm not at all concerned about a software sprite routine that pre-shifts or generates what I see on screen. All that gets binned and in its place I have the Jaguar's OP do what it does best in a way that makes sense given the required results on screen.

 

Well, I mean, I'm not... because I'm not a coder... but even I can see that's not how to go about a game source port.

You're confusing source ports with the ports like CyranoJ has been doing, which is the type of port being asked for. Virtually NO Genesis games have the source released, and therefore there will be NO source ports. In which case, porting IS more like emulating.

 

 

Anyway, all completely moot points because of not only what travis says above, but the fact that, from the point of view of whoever is doing it, porting is the dullest and least creative exercise someone could wish to waste away their time with... probably best left to those without an ability for creative expression or understanding of how to build games that work from the ground up, but with a desire to just do something for the sake of doing something. And this is the main reason why not so much actual porting takes place...

And that is the biggest load of crap I've ever heard. It certainly is clear you are not a coder. That sounds more like an attempt at insulting certain coders than anything else. If it wasn't meant as an insult, you really found the worst possible way of wording what you meant to say. Porting is very often one of the most challenging tasks a programmer can do. Even with the source, making a game meant for one platform look it best on a completely different one is a challenge most programmers aren't up for. Programmers who do source ports make good money because they're in high demand.

[+CyranoJ]

And that is the biggest load of crap I've ever heard.

 

Try reading your previous post about DMA. That should solve that problem for you.

[Chilly Willy]

Try reading your previous post about DMA. That should solve that problem for you.

Excuse me, but I was defending YOU. Did you actually read what he wrote?

 

but the fact that, from the point of view of whoever is doing it, porting is the dullest and least creative exercise someone could wish to waste away their time with... probably best left to those without an ability for creative expression or understanding of how to build games that work from the ground up, but with a desire to just do something for the sake of doing something.

That's him talking about everything YOU have been doing here lately. All those ST games you've ported for Jaguar folk - he's spitting in your face, so don't go spitting in mine when I defend you.

 

Anywho, I went back and checked some old ST code, and it's not DMA, but using the HBL ints to change all the palette registers. A simple mistake given how long it's been since I did anything for the ST. You don't need to be snotty about it... especially as I'm on YOUR side.

[twoquickcapri]

 

[BillyHW]

When I first read this thread, I though to myself, hey it would be cool if somebody ported Genesis Snow Bros. to Jag. But then I thought to myself, Jag is a next gen system compared to Genesis, why not port Snow Bros. 2 over from the arcade instead? That would make more logical sense. And it would make more sense to port over some 32X games. Or maybe even SegaCD and Saturn.

 

Not sure who will do it all. I don't know how. But someday I'd to learn how to do some C64 programming and maybe finish Ghosts'n Goblins. (It's missing levels, which is pretty unforgivable for a floppy disk game, considering they could have just added a second disk.)

[+CyranoJ]

 

 

Excuse me, but I was defending YOU. Did you actually read what he wrote?

 

First off, I don't need defending. Second off, he's talking about PORTS.

 

 

 

That's him talking about everything YOU have been doing here lately. All those ST games you've ported for Jaguar folk - he's spitting in your face, so don't go spitting in mine when I defend you.

 

Not a single one of those is a source code port. They're more like emulation than porting. If you knew anything about how they worked, you'd know that. And he's right, I've only done one source port (Beebris) and that was from my own game. And it was deadly boring to do. I'd much rather be doing anything else.

 

Also, he's sh3-rg of Reboot. You know, that group I'm the coder for?

 

 

Anywho, I went back and checked some old ST code, and it's not DMA, but using the HBL ints to change all the palette registers. A simple mistake given how long it's been since I did anything for the ST. You don't need to be snotty about it... especially as I'm on YOUR side.

 

I really don't need someone who does this on my side, kthnkxbye. Wot no wikipedia entry on ST for delicious copypasta?

 

You also said that 'emulating the colour changes per line' would not be a big deal.. I'd like to know how you came to that conclusion.... what Jaguar mechanism are you proposing to use to emulate that function? (Note, I've already done this, and no, it wasn't at all easy) - I suppose you could disassemble one, change the labels, and say you worked it out yourself. *shrug*

Edited February 7, 2015 by CyranoJ

[sh3-rg]

You're confusing source ports with the ports like CyranoJ has been doing, which is the type of port being asked for. Virtually NO Genesis games have the source released, and therefore there will be NO source ports. In which case, porting IS more like emulating.

 

You're confusing 2015 with 2004. Go read the OP. You made a silly assumption.