beta version of CZ80 released :)

ethoscapade · Post by **ethoscapade** » Mon Jan 24, 2005 1:48 pm

wow, i had given up on this.

fantastic job, stef.

so... this being the spark that starts a whole new round of releases...

where are the releases?

Untamed · Post by **Untamed** » Mon Jan 24, 2005 4:30 pm

Hawq wrote:Dont forget watches & musical xmas/bday cards, the Z80 just wont die ever it seems

Let's emulate musical bday cards on the Dreamcast!

Link2k4 · Post by **Link2k4** » Mon Jan 24, 2005 11:38 pm

Untamed wrote:
Hawq wrote:Dont forget watches & musical xmas/bday cards, the Z80 just wont die ever it seems

Let's emulate musical bday cards on the Dreamcast!

ROFLMAO

GPF · Post by **GPF** » Tue Jan 25, 2005 8:46 am

Untamed wrote:
Hawq wrote:Dont forget watches & musical xmas/bday cards, the Z80 just wont die ever it seems

Let's emulate musical bday cards on the Dreamcast!

Thats just what we need people trading in musical xmas/birthday rom warez

Hey does anybody have the new Rudolph xmas card rom ? lol

doragasu · Post by **doragasu** » Tue Jan 25, 2005 3:09 pm

And also All gameboys have a Z80 (even the GBA, for backwards compatibility with older gameboys).

Sir Savant · Post by **Sir Savant** » Tue Jan 25, 2005 4:00 pm

I think I have that rom, here is a link to it.

http://www.darksavant0.com/files/rudxmacard.ton

YAY, more emulators!

Alexvrb · Post by **Alexvrb** » Thu Jan 27, 2005 3:33 pm

Well, the Zilog chip was certainly superior in many ways to the 8080 is was compatible with. But in the next era of chips, they screwed up. So the Z80 continued to see new versions in more and more focused enviroments, but there was no popular successor. Heck, at one point they even had plans to make an x86 compatible chip as well, but they of course chickened out because they as a company preferred floundering.

Also, I can't believe nobody mentioned GB and GBC when talking about Z80. While they may not have succeeded with Z800 or whatever they called their planned successor chip, they did manage to get the good old Z80 to be very power efficient. My TI-83 lasts for many hours on those AAAs.

Untamed · Post by **Untamed** » Thu Jan 27, 2005 4:24 pm

GPF wrote:
Untamed wrote:
Hawq wrote:Dont forget watches & musical xmas/bday cards, the Z80 just wont die ever it seems

Let's emulate musical bday cards on the Dreamcast!
Thats just what we need people trading in musical xmas/birthday rom warez

Hey does anybody have the new Rudolph xmas card rom ? lol

http://www.cardwarez.tk

...

If only that site were real.

Stef.D · Post by **Stef.D** » Thu Jan 27, 2005 6:18 pm

I was going to post that on DcEmu.co.uk forum, but site is down for now.
I quickly set up an autoframe skip feature for Genesis Plus.
I'm even surprised i never did it before, it took me about 2 mn to do it (it worked on first attempt). Actually all was already here : a function to know where is the current read position in sound buffer, streaming sound etc ...
I modified about 10 lines of code to get it running.
Code is a bit ugly, but it was just a test ... and it worked directly almost perfectly

I give only the sources since anyway with my built, autoframe skip make Genesis Plus almost unplayable because we have something as 3-4 FPS ! Software renderer is too slow, and seems that sound code is not nice too.

BlackAura> I mainly modified the snd_stream_poll function which now return the number of samples still required to fill sound buffer. Beside that, i compare this number with the sound buffer size for 1 frame (42000/60 for 42 Khz)... if it's greater then i do a frame skip (no VDP display) else i do complete frame render.... simple but efficient.
Now sound code need to be reworked and optimised. I remember i did that in rush just to get stuff working... but that's not optimised at all.

You can download my last Genesis Plus DC sources here :
http://gens.consolemul.com/download/GenPlus_DC.zip

BlackAura · Post by **BlackAura** » Thu Jan 27, 2005 6:43 pm

Ooooh... Neat.

Well, this is a bit simpler than what I had in mind. For some reason, I didn't think of using the sound output to control the emulator. Duh...

Assuming it works correctly (I'll throw it into my copy, play a few games, and see if it blows up or not), there's really only one thing left to do to get it working properly - decrease the size of the buffer to reduce the sound delay.

As for optimizing it, off the top of my head...

Remove the mixing code in GP that mixes the two mono buffers into a single stereo buffer
Remove the unmixing code in the sound driver that unmixes a single stereo buffer into two mono buffers
Use DMA to transfer the sound data directly from the buffers
Find places where we're needlessly copying sound data, and put a stop to it
There's probably a few places we can simplify things
Try using the Gens sound system, which might be faster than the MAME one

If I remember correctly, the Gens sound system outputs as 32-bit values, and does all it's own mixing, right? I don't suppose there's any way to get it to output 16-bit values in a format we can transfer directly? If we have to convert back to 16-bit samples, we might lose any speed gain that we might get.

The way I had the system running in a PC test version of Genesis Plus was basically running the DAC emulation / FM timers each scanline, and then running the PSG and FM synths for an entire frame of audio at once, at the end of the frame. Probably not the most accurate way to do it (it'll break at least one game), but it seems to work well enough.

sakuragi · Post by **sakuragi** » Thu Jan 27, 2005 6:47 pm

Bravo Stef

congratulations for all your work. Je me suis inscrit ici juste pour te dire bravo ^^. You think we can have a version of genesis plus with good sound in few times ?

BlackAura · Post by **BlackAura** » Thu Jan 27, 2005 6:55 pm

Hang about... I just downloaded the source you linked to, and I can't find anything even resembling what you just described.

Salamander2 · Post by **Salamander2** » Thu Jan 27, 2005 9:15 pm

Please, dont forget about the MSX2 and sega Master System emulation.

DcSteve · Post by **DcSteve** » Thu Jan 27, 2005 9:28 pm

doesnt stef's source use software rendering, so what happens when u switch the sound changes from stef's builds into BA's built. Im pretty sure sound would be loud and clear now with hardware rendered:)

Stef.D · Post by **Stef.D** » Fri Jan 28, 2005 3:10 am

BlackAura>

Ooooh... Neat.

Well, this is a bit simpler than what I had in mind. For some reason, I didn't think of using the sound output to control the emulator. Duh...

Actually we have 2 choices to synchronise emulation speed : Video Synchro (VBlank) or Sound synchro (Sound buffer wait).
Unfortunatly, we can't have perfect synchro for both of them.
If we choose to synchronise on V-Blank, we will have some annoying noises in sound (except if we interpolate it, but sound is then a bit distorded).
If we choose to synchronise on Sound Buffer (it's what i'm doing in Gens) then we'll have sometime some tears on the screen... we can always wait for VBlank but then we will miss some frames :-/

In my viewpoint, sound synchro is far more important, i really dislike having noises in sound, it's so irritating :p

What i'm doing in Gens : i'm just comparing the "current read segment" against "current write segment" in sound buffer... while i can write new sound segment without raising "current read segment" i do frame skip, else i do a complete frame... and i'm waiting for writing a new segment without overlapping "current read segment"... what i call segment is the sound buffer for a frame (buffer lenght = 44100 Hz / 60 Hz)

Assuming it works correctly (I'll throw it into my copy, play a few games, and see if it blows up or not), there's really only one thing left to do to get it working properly - decrease the size of the buffer to reduce the sound delay.

Hey, don't erase your sources ! mine are really old

At least you can copy the snd_stream.c file and maybe doing some hand modifications to system_frame function because i assume you modified it.
I also modified the main loop (function emu_run in main.c) which normally does manual frame skip.

As for optimizing it, off the top of my head...
- Remove the mixing code in GP that mixes the two mono buffers into a single stereo buffer
- Remove the unmixing code in the sound driver that unmixes a single stereo buffer into two mono buffers
- Use DMA to transfer the sound data directly from the buffers
- Find places where we're needlessly copying sound data, and put a stop to it

There's probably a few places we can simplify things

- Try using the Gens sound system, which might be faster than the MAME one

Well, you're right, there are many ways of optimising the sound code, and we should use all these you mentionned

My built already use the Gens sound core, but it doesn't performs well on DC, it's almost as fast as MAME core :-/ i think it's due to it memory usage (use 32 bits, does more memory buffer access when updating...)
I think the best thing to do is to use an old MAME version (0.35 or 0.36) of the core (newers are quite slow and not really more accurate).

If I remember correctly, the Gens sound system outputs as 32-bit values, and does all it's own mixing, right? I don't suppose there's any way to get it to output 16-bit values in a format we can transfer directly? If we have to convert back to 16-bit samples, we might lose any speed gain that we might get.

Yeah, Gens sound engine work in entire 32 bits, because today's CPU computes 32 bits datas faster than 16 bits ones, and it was easier for final mixing. Unfortunatly on DC that doesn't help much, since it also takes x2 more memory.

The way I had the system running in a PC test version of Genesis Plus was basically running the DAC emulation / FM timers each scanline, and then running the PSG and FM synths for an entire frame of audio at once, at the end of the frame. Probably not the most accurate way to do it (it'll break at least one game), but it seems to work well enough.

It's the most common way of doing

PSG is used as DAC in AfterBurner 2, so this game won't product voice with this method, but that's not really important compared to the speed gain

Hang about... I just downloaded the source you linked to, and I can't find anything even resembling what you just described.

I just checked the sources on the site, and they are correct.
As i said, that need very minors modifications compared to the old sound code. Just check in the snd_strem_pool function in the snd_stream.c file, now i do :

Code: Select all

return (needed_samples - got_samples);

at end of function to return the number of samples yet required...

then in system_frame(...) i also did some minors modification :

Code: Select all

if(snd.enabled)
{
    if (audio_update() >= snd.buffer_size) return 1;
}

returning 1 mean i want a frame skip for the next frame, else i return 0

By the way, i used the Z80 CPU interface as you can see, and it works

That will probably help you to fix it... if needed. CZ80 seems to work pretty nicely actually

Sakuragi>

Bravo Stef congratulations for all your work. Je me suis inscrit ici juste pour te dire bravo ^^. You think we can have a version of genesis plus with good sound in few times ?

Merci

Pour la prochaine version, je pense qu'il vaut mieux voir avec BlackAura

J'ai juste modifi? la gestion du frameskip, mais au niveau du VDP je n'ai rien chang?, et c'est le plus important ? mon sens car sur ma version c'est injouable tellement c lent !

DcSteve>

doesnt stef's source use software rendering, so what happens when u switch the sound changes from stef's builds into BA's built. Im pretty sure sound would be loud and clear now with hardware rendered:)

Yeah my sources still use the software renderer and it's unplayable because it's slow as hell... sound code seems to be pretty slow also. I don't expect the BA version can run at full speed with sound enable... close to full speed, but not really full speed.

DcSteve · Post by **DcSteve** » Fri Jan 28, 2005 4:56 pm

so BA> did anything good happen to the sound after incorperating these changes into your source?

Post by **Quzar** » Fri Jan 28, 2005 11:22 pm

DcSteve wrote:so BA> did anything good happen to the sound after incorperating these changes into your source?

do you REALLLY think he wouldnt post that information anyways without you asking? and as a secondary note to that, if he wasnt going to post it, do you think you asking him would change his mind about posting it if he wasnt going to?

relax. go work on something instead of nagging him.

MetaFox · Post by **MetaFox** » Sat Jan 29, 2005 4:02 am

Well said quzar, it seems you and I are thinking on the same wavelength lately.

If you want to say something, but don't want to come off as a jerk, I say it. Likeways if I want to say something, but don't want to come off as a jerk, you say it.

It's getting kind of creepy.

Salamander2 · Post by **Salamander2** » Sat Jan 29, 2005 11:29 pm

My question is WHEN.

Post by **Quzar** » Sat Jan 29, 2005 11:38 pm

Salamander2 wrote:My question is WHEN.

when what?