What is the Reason for Slow DreamSNES?

Ian Micheal · Post by **Ian Micheal** » Mon Aug 11, 2003 2:55 am

Well I beleive rand the bleemcast creator could. the guy is really , really good. Even little tips he has given me some times by reading his posts made a lot of change in my thinking. Well since you cant use the 3D hardware to help then your about right fullspeed with out short cuts is not going to happen at all. Compatable-ness , drops speed even further. Fully optimize for a few games only. Then fullspeed might be able to be done using underclocking and a very low sample right. Zero frameskip fullspeed with out it being a bought product i would very much like to be proven wrong its not going to happen. but some times im wrong and my wife marks it on the calander. heh!.

This was based on info that Dreamsnes CPU and SPU were SH4 based if there were and this last release was the speed then fullspeed emulation would not be able to be done.

I was just corrected and told by black aura that dreamsnes is still unoptimized straight C which totaly changes my mind on what it can do in the future. i hope that explains were i was coming from.

BlackAura · Post by **BlackAura** » Mon Aug 11, 2003 7:31 am

Erm... You do know that they haven't really tried to speed the emulator up yet? They were working on compatability first, speed second - it's easier to improve unoptimised code than it is to improve optimised code. It's be silly to make it faster, and then fix all the bugs, because fixing the bugs will slow it down again. It's better to fix the bugs, then speed it up.

It should be possible to get SNES emulation running at full speed - just look at Bleemcast, which ran Playstation games at full speed, better than a real Playstation can. That's probably the upper limit of what the DC can achieve, but a SNES emulator at full speed should be possible.

As far as I recall, the biggest slowdown in DreamSNES is the sound code, followed by the rendering code. Both of those are still written in unoptimised C. It should be possible to get the emulator running faster if those parts are optimised, or re-written for the Dreamcast.

Give them time. Until they say they can do no more, I'd say that they're working on it, and they may yet suprise us all.

Ian Micheal · Post by **Ian Micheal** » Mon Aug 11, 2003 7:46 am

Good to hear, i was told that both the main cpu and spu were using sh4 asm thats what my comments were based on and if that had no effect not much would my mistake. and the fact the SH4 chip is not built for number crunching and dreamsnes cant use the real power of the dreamcast which is its 3D power. so it was simple logic to come to that anwser. Bleemcast used the dreamcasts 3D hardware if it was using framebuffer access it be running like the PSX emulator im working on.

I was given the wrong info on the project so that changes what is possable . If most of it is still just C then im wrong on my comments so i will edit it now.

# I edited my above post to now include the point, I was told was not correct and that Dreamsnes uses no asm what so ever. now that know that it makes fullspeed emulation, doable unlike if both the cpu and spu were SH4 asm as i was told.

So in simple terms its still unoptimized C and can attain fullspeed with some rewrites.

hope that clears that up. now that i know its just unoptimized c fullspeed i think can be done.

BlackAura · Post by **BlackAura** » Mon Aug 11, 2003 8:15 am

The main CPU emulator is in SH-4 assembly, but the rest of the emulator isn't. Since the SNES's CPU isn't very fast (between 1 and 3MHz, depending on the game), I don't think the DC would have any problems whatsoever with that. It's all the additional hardware that really slows things down, especially the SPC700's DSP hardware, and the unbelievably complex (for a 2D system) graphics hardware this thing has.

It should be possible. And considering how long it'd take to implement, and how long it's been since the last release... Well, I can be optimisitic if I like, can't I?

Ian Micheal · Post by **Ian Micheal** » Mon Aug 11, 2003 8:44 am

Yeah man never hurts makes the world a happer place.

Rand Linden · Post by **Rand Linden** » Mon Aug 11, 2003 11:46 am

This has been discussed over and over to death -- why don't people just use search?

Search is your friend... Search *wants* to help... Search has all the answers...

Full speed SNES is very possible to achieve -- but not likely because of the time required to do it.

Rand.

curt_grymala · Post by **curt_grymala** » Mon Aug 11, 2003 12:26 pm

Rand Linden wrote:This has been discussed over and over to death -- why don't people just use search?

Search is your friend... Search *wants* to help... Search has all the answers...

Yes, but you can't win for losing. I try to do that whenever I have something to say about an old topic, but then I get flamed for "bumping".

Celauve · Post by **Celauve** » Mon Aug 11, 2003 1:50 pm

I know it's been talked about to death, but it gives me something to do. Anyway, can any of you figure out why Seiken Detsetsu 3 does that blasted flash every time a text box comes up? lol

BlackAura · Post by **BlackAura** » Mon Aug 11, 2003 5:32 pm

Bug? Check the buglists.

-Johnick- · Post by **-Johnick-** » Mon Aug 11, 2003 8:10 pm

impact135 wrote:
It just baffles my mind how a 200mhz machine has trouble emuating a machine thats 50x slower. .

My Athlon XP2000 is 50x more powerfull then the Sega Saturn and i still cant play Radiant Silvergun at full speed in Giri Giri.The reason being the Saturn's dual sh2 processors are a nightmare to emulate.The sooner people stop measuring computers speeds by clock cycles alone the better, otherwise we all might aswell get Celerons

impact135 wrote: The genesis emulator (i cant mention the name here) is FULL SPEED with sound (the sound is crap though).. and the genesis is faster then the snes.

The Genesis/Megadrive had a faster cpu............thats it.It could only handle 64 colours on screen at once from a pallete of 32768 with no special effects or transparencies.The Snes could have 256 from a pallete of 16777216 colours, it could do transparencies and it could scale/flip/rotate sprites at will.The Genesis had 8bit sound while the Snes was the first console to have real 16bit fm stereo sound.

BlackAura · Post by **BlackAura** » Mon Aug 11, 2003 9:54 pm

Erm... no. The Genesis used digital FM synthesis, which (I think) used a 16-bit DAC. The SNES used a totally different principle for producing sound - it plays back short sound samples of instruments, as the Amiga does.

-Johnick- · Post by **-Johnick-** » Tue Aug 12, 2003 11:47 pm

BlackAura wrote:Erm... no. The Genesis used digital FM synthesis, which (I think) used a 16-bit DAC.

My bad, must have been thinking of the PC-Engine/TG16 (didnt that have 8bit sound ?).Still, the Snes still blew the Genesis out of the water sound wise.

BlackAura wrote: The SNES used a totally different principle for producing sound - it plays back short sound samples of instruments, as the Amiga does.

Yea like midi, but it could still reproduce sounds like speech far better then the Genesis.Listen to the intro for Tales of Phantasia, the Genesis could never pull off sound of that quality.

BlackAura · Post by **BlackAura** » Wed Aug 13, 2003 12:43 am

Well, not really like MIDI. MIDI is just a system for transmitting musical notation. It's more like wavetable synthesis, or Amiga-style MOD music.

Ian Micheal · Post by **Ian Micheal** » Wed Aug 13, 2003 3:50 am

There were a few genesis games that had nice music the jap first version had much better sound then the other genesis's later on. i own it and there worlds apart from the PAL megadrive and the us genesis. I would have to record it for any one to hear the change is it noticable. I realy dont think the snes had that great sound.

FlashPV · Post by **FlashPV** » Wed Aug 13, 2003 8:39 am

Listen any Genesis game with a soundtrack made by Yuzo Koshiro and you'll see that the Genesis is able to produce some great music

BlackAura · Post by **BlackAura** » Wed Aug 13, 2003 10:20 am

It's all a question of how it was used. FM synthesis can create some fantastic sounding tunes, provided it's done properly. It's kinda like the difference between NES and SMS music - the NES had technically superior sound hardware (just about) but it was hardly ever used properly, so (in my opinion) most SMS games had better music. Even if it was the same game, the SMS versions sounded better. But some of the stuff I've heard produces by a NES was far superior - it's just a shame that it was never used in a game.

There's no point in having something in a console if nobody can use it properly. Unfortunately, FM music is a little tricker to do than sampled music, so the SNES games tended to have better sounding music most of the time.