Old Regen pages

Sik · Post by **Sik** » Tue Apr 29, 2008 9:08 pm

Stupid question: does Regen support VDP's mode-4? Yeah, the Master System mode. I know no MD games should be using it, but now that I come to think on it, things such as the stretching part of the Nine Pixels demo can only be reliably done in mode-4 because the scrolling is done using the registers rather than memory, and the effect is immediate (so this would allow for horizontal stretching).

Also supporting it would just make for accuracy, right?

AamirM · Post by **AamirM** » Wed Apr 30, 2008 1:35 pm

Hi,

How it will be more accurate when no software requires it?

stay safe,

AamirM

King Of Chaos · Post by **King Of Chaos** » Wed Apr 30, 2008 1:53 pm

It'd be for the sake of more accurate complete Genesis hardware emulation. Who knows, maybe you can emulate sticking Master System games into the Genesis itself and see what happens?

Zoomer · Post by **Zoomer** » Wed Apr 30, 2008 2:35 pm

Hi AamirM again. It'll be great if I'll can chose on what monitor ReGen should go fullscreen. For example window of Regen is on my first monitor and when I switch to fullscreen - Regen goes on my TV.
Also there is still no selection of rom from archive (in case you forgot that

)

AamirM · Post by **AamirM** » Wed Apr 30, 2008 2:51 pm

Hi,

@ Sik and King of Chaos

If I see any game that relies on it and runs correctly on real Genesis and not in Regen then I'll add it.

@ Zoomer

Yes, I didn't add many requested front-end related things. I have also said this in the History.txt and am sorry for that. The thing is that I always focus more on correcting and perfecting emulation than adding new features. The ROM archiver would've made it into 0.85 if I wasn't lazy enough to add 7zip support to it (I think more people want this, I have implemented browsing from zip file featue. See the resource file with reshacker or something). And to be honest I am not working on the Windows version right now. I am working on making the Linux people happy now. I think the linux version is long due but I have been unable to find some free time nowadays.

stay safe,

AamirM

Sik · Post by **Sik** » Wed Apr 30, 2008 4:18 pm

AamirM wrote:@ Sik and King of Chaos

If I see any game that relies on it and runs correctly on real Genesis and not in Regen then I'll add it.

You added the supervisor and user 68k modes to Regen and no other emulator supports it because no games use it. So I guess it would make sense

Besides I've just thought in some trick that would only work in mode-4 but not in mode-5 due to the way scrolling is done (mode-4 uses registers and they may work in the middle of a scanline, mode-5 uses VRAM and VSRAM and definitely they won't work in the middle of a scanline).

AamirM · Post by **AamirM** » Wed Apr 30, 2008 4:40 pm

Hi,

Sik wrote:You added the supervisor and user 68k modes to Regen and no other emulator supports it because no games use it.

No it does not. What led you to believe that? I guess you are talking about address error exception emulation. Well Tiido made a program that used this flaw in emulation so I added it. And you are partly responsible for it being added because King of Chaos posted your post from SonicRetro forums (you are Sik the Hedgehog...right?) onto ZSNES forums bringing my attention to this and so I knew of Tiido's emu detector.

Secondly, there is nothing to test against if my mode 4 really works.

stay safe,

AamirM

Shiru · Post by **Shiru** » Wed Apr 30, 2008 4:48 pm

Sik, make program which will use this mode (not 'hello world', of course), this will be reason to emulate it. If there no software which uses this mode, how Aamir can make working code? Or do you offer him to write SMS emulator first?

Sik · Post by **Sik** » Wed Apr 30, 2008 5:51 pm

AamirM wrote:
Sik wrote:You added the supervisor and user 68k modes to Regen and no other emulator supports it because no games use it.
No it does not. What led you to believe that? I guess you are talking about address error exception emulation. Well Tiido made a program that used this flaw in emulation so I added it. And you are partly responsible for it being added because King of Chaos posted your post from SonicRetro forums (you are Sik the Hedgehog...right?) onto ZSNES forums bringing my attention to this and so I knew of Tiido's emu detector.

Yes, I'm the same. Seriously, if you added it just for the sake of accuracy, then you should add it too. Simple as that.

And yes, I would make a program, but be warned it would take time to check if what exactly I want to do works (it isn't exactly a simple trick - well, it is, but the code would be an epic mess).

AamirM · Post by **AamirM** » Wed Apr 30, 2008 5:59 pm

Hi,

My way of thinking: if it works on real thing it should work on Regen. So if your test program runs fine on real thing I will try to make it work under Regen. Although it may not be immediatly implemented because I don't have a working Megadrive anymore so my testing and researching abilities are limited now. So take your time making the test program.

stay safe,

AamirM

TmEE co.(TM) · Post by **TmEE co.(TM)** » Wed Apr 30, 2008 6:37 pm

Well, if Regen would work fine under 98SE, I'd create a really mean emu detector that tells you on what its running on... it will require pretty much perfect emu to pass

(there's SOOOOO many not so well, if emulated at all, features regarding YM2612 for example...)

Sik · Post by **Sik** » Wed Apr 30, 2008 6:41 pm

What about the SRAM trick?

If you put an invalid address for SRAM in the header, you'll immediately know if there's an emulator or not (whenever it emulates SRAM or not).

TmEE co.(TM) · Post by **TmEE co.(TM)** » Wed Apr 30, 2008 7:48 pm

Emulators don't care if the SRAM address is there or not... they will emulate SRAM as much as its accessed in area 200000....20FFFF after writing 1 to A130xx

Sik · Post by **Sik** » Wed Apr 30, 2008 8:20 pm

I thought Sonic 3 had SRAM at $300000. Imma check later. Anyways, seriously, am I the only one that expects emulators to respect the header? Sega is very clear about how SRAM is to be specified in the official docs >_>

TmEE co.(TM) · Post by **TmEE co.(TM)** » Wed Apr 30, 2008 8:26 pm

Duke Nukem 3D didn't put the SRAM info in its header, yet it uses it... I put all kinds of stuff into my ROMs header... and I expanded the standard a little too... added MicroWire EEPROM there.......