Theoretically Speaking, Is The Pandora At Least Capable Of Dreamcast E

[jbrodack]

i doubt its going to even be as good as psx on gp2x. dreamcast is more powerful than people gave it credit for. yeah, you will have a port of an emulator for dc but don't get your hopes up for anything near fullspeed. something running on a psp doesn't mean much. if someone put enough time and effort they could probably have a dc emulator "running" on the gp2x at 0.5 fps on menus.

if you want portable dreamcast emulation get a good laptop.

 

[Exophase]

not sure i follow there... does he just mean that he is emulating an under clocked DC? if so that is obvious from the videos i believe i remember seeming the clock being 30mhz ish which is way lower than the DC... sorry can't check myself on dialup atm

That's what he's saying, but it's not at all obvious that that's what those numbers mean.

The one problem with all of this is that no one really tries to get CPU timing accurate for more recent CPUs, especially one with a lot of scheduling variables like SH4, and some major variables with cache performance.

SH4 can execute up to two instructions per second. So the theoretical max is 400 million cycles per second. Real code could run at this, but it probably wouldn't be useful code. In normal code the number is lower, first because you can only execute some kinds of instructions at the same time. Then because of stalls for various multi-cycle instructions, branches. And possibly most significantly because of cache misses (Dreamcast's caches are only direct mapped too). What lxdream and nullDC consider to be "normal" Dreamcast execution speed is 0.5 instructions per cycle (or 2 cycles per instruction). That's one fourth the theoretical maximum, and while I don't know where they got this number I'm sure it's a lot closer to the overall average than the maximum is. At least Dreamcast games seem to be okay with it, by and large.

What the PSP videos are running at is 6 cycles per instruction. So with all things scaling evenly that's 1/3rd the Dreamcast's clock speed, except a real Dreamcast at 66MHz would probably execute more than that because the cache penalties wouldn't scale with the clock speed (unless the bus was lowered too). I have no idea what the compatibility is like at this. If it's still pretty good then it shoots major holes in the arguments anyone uses for CPU speed in console games, although psx4all kind of does this already.

 

[conso]

I'm predicting that this thread will become a boulevard of broken dreams.

balls of steel

Damn it. Do you really think it is necessary to remind everyone to be not to optimistic every day? When it comes to dc-emulation there are quite some realism-nazis around.

I have no idea if it will be possible or not. I'll wait if we will see a near fullspeed emulator at some point, but nobody can proof it is impossible. Really, no way to proof this, all speculations on both sides, only difference is the pessimists think they are clever for being pessimistic. B)
Only way to stop this would be a natural agreement, that everybody here telling us it is impossible or we should be realistic will loose a finger once a near-fullspeed emulator is available.

 

[icurafu]

Good point. I would also like to rewind my pessimistic statements made in regards to N64 on GP2X.

I have a feeling I will be keeping my finger.

 

[Lord_Doku]

http://pspupdates.qj.net/New-video-clarifi...g/49/aid/122851

read the bit below the vid. thats just awesome.


EDIT: Merged with existing DC thread - Chip

 

[Lord_Doku]

posted an thread about the dreamcast here, and the link in it says all.

 

[Fishbong]

Although we already have a thread on DC emulation, i must say, this is great news. I'm still sceptical if playable speed is a possibility even on the Pandora, but we can always hope, and the dev seems optimistic.

Reading through the comments though, i wonder why anyone would want to dev for the PSP. The community is made up of some of the worst idiots on the whole internet. And to think people here get angry when someone asks for a WINE port

 

[Lord_Doku]

agreed, the comments there reek of fail....massive fail. the reason internet is seen as stupid is cuz of these people and others like em.

anyway, now theres even more reason for me to get an pandora. i might scrap my plans on buying an 360 now.

 

[jakshep2]

I reckon it's theoretically possible but it will be nearly at the end of the pandos lifespan before it gets perfected.

We should ask the guy for the nullDC sourcecode.

 

[Firefox]

SH4 can execute up to two instructions per second.

 

[TyBO!]

Excellent news!

I remember how much zod's Playstation emulator benefited from a dynarec; I'm sure it will do wonders for Dreamcast emulation as well. Granted, there will need to be a brand new dynarec for Pandora's ARM processor, but the devs of nullDC seem rather serious about working on the Pandora.

 

[nate9771]

wow thats impresive,it could happen.

 

[Exophase]

SH4 can execute up to two instructions per second.

Oops :>

Jaguar is probably another good arch for this discussion. The RISC CPUs can perform instructions in as little as 1 cycle but because of register dependencies they'll be stalled all the time. I doubt a Jaguar emulator would emulate this if it wanted high performance, unless it had a recompiler, so effectively cutting the number of cycles per second would work to the same effect. Unfortunately these stalls probably varies a lot from game to game.

 

[jaycee900]

This is fantastic news, it imo brings a playable DC emulator closer to reality on the Pandora..i doubt the PSP port will get higher than say 10-12fps which is still a feat itself and maybe more who knows, but with more ram and a faster CPU in the Pandora a pretty decent DC emulator is a bloody dream come true...i mean Speed Devils on handheld! Where's that bloody tornado!

 

[MagicPants]

For every page in this thread the Pandora gets 10% faster and DC emulation gets 10% easier. We're almost there! :rolleyes:

 

[quadomatic]

We should ask the guy for the nullDC sourcecode.

Damn, do you ever pay attention?

drkIIRaziel. the maker of nullDC, is porting nullDC to PSP so that the source code can be released, from which the emulator can be made for other embedded platforms. He's also porting nullDC to Pandora once he gets it.

 

[TaG]

We should ask the guy for the nullDC sourcecode.
Damn, do you ever pay attention?

drkIIRaziel. the maker of nullDC, is porting nullDC to PSP so that the source code can be released, from which the emulator can be made for other embedded platforms. He's also porting nullDC to Pandora once he gets it.And from his blog:QUOTE
The code will be open sourced as soon as it gets stable.

 

[gibberish]

I reckon it's theoretically possible but it will be nearly at the end of the pandos lifespan before it gets perfected.

We should ask the guy for the nullDC sourcecode.

i know you mean well but please stop posting rubbish.

 

[jbrodack]

people dev for the psp because its the most widely available handheld out there that is also fairly powerful. this means more devs are likely to have one, more resources are available to devs, and they have the largest possible audience for their work.

of course the psp community isn't as tight knit as this one (pandora and gp2x) and the our systems are more open plus the pandora will be quite a bit more powerful than a psp.

just responding to fishbong saying why even dev for the psp.

 

[CyruzDraxs]

For every page in this thread the Pandora gets 10% faster and DC emulation gets 10% easier. We're almost there! :rolleyes:

Maybe if we make it to 100 pages we'll get fullspeed PS3 emulation!