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#59738 03/07/10 01:21 AM
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Hello all,
Just a little question for to use Genesis 32x driver. Somes games need to be started with PAL system, so, actually, 32x is only based at US system or no?
Its possible to add Pal based system to start this game?
For example: Virtua Fighter (Europe)


Last edited by Multipass; 03/07/10 01:28 AM.
Multipass #59740 03/07/10 02:20 AM
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the code just doesn't have pal support enabled right now.

you're not missing anything, none of the pal specific games actually work better.

Haze #59756 03/07/10 10:37 AM
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Originally Posted By Haze
the code just doesn't have pal support enabled right now.

you're not missing anything, none of the pal specific games actually work better.
maybe he wants to play in his mother's language

ReadOnly #59757 03/07/10 10:41 AM
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Originally Posted By MESSfan
Originally Posted By Haze
the code just doesn't have pal support enabled right now.

you're not missing anything, none of the pal specific games actually work better.
maybe he wants to play in his mother's language


then he should use another emulator, you're not going to do much playing with the 32x driver.

Haze #59758 03/07/10 11:14 AM
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Quote:
then he should use another emulator, you're not going to do much playing with the 32x driver.


Wrong, some games work, and in full speed too wink

Dr.Zer0 #59762 03/07/10 12:26 PM
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Originally Posted By Dr.Zer0
Quote:
then he should use another emulator, you're not going to do much playing with the 32x driver.


Wrong, some games work, and in full speed too wink


I know what works and what doesn't, I wrote it. It's very bad. Some games run better than they should even, because on real hardware waitstates cripple them. However, that doesn't mean the driver isn't terrible, the new sound hardware isn't emulated at all, things could break at any given moment due to inaccurate timings, and a lot of things simply don't work.

The original hardware was so bad that developers just shipped things if they 'worked', even if the underlying code was buggy as hell and relying on all sorts of weird timings or quirks of he hardware. I'd actually consider it the worst, and most fundamentally flawed add-on for any system ever. Even just doing a good 2d game on it gave you less video power (due to it being cpu and memory-access bound) than trying to do it with the plain MD hardware.

Even if it's just about the most simple add-on you could think of (2 SH2s, a framebuffer and a DAC) Emulating it well is nasty, and the MESS emulation is awful beyond words. Using it by choice, for any other reason than attempting to improve the driver is simply crazy.

Impoving it in MESS is hard too. From what I'm told (and what other emulators do) anything reading the FIFO buffers is meant to stall until it has data to read, MAME/MESS simply can't do this, you have to return something from a read. Kaotix at least does that, making no real attempt to properly sync the cpus during a massive FIFO based operation. I'd be curious to know if it really stalls the CPU on the read opcode on real hardware, or if that's just a kludge in other emus to get around needing cycle exact timing of everything. I'm told the former, but I still wonder if it's the latter.

Also even simple things don't make sense. The framebuffer mirror that's meant to handle transparency works in most cases, but then you have games like Spiderman and World Series Baseball which write data to the normal area, and expect the transparent pixels to be stripped out as if it was writing to the special mirror. (Maybe it needs the buffered writes, but I can't really see how that would fix anything really)

Increasing the interleave to perfect rates actually breaks some games too, again due to timing issues, and race conditions between the cpus etc. because memory contention and the delays it causes aren't emulated and so increasing interleave only makes some cases *worse*. (Kolibri IIRC)

Some games appear to work but break randomly (Tempo when you pick certain things up)

I hate the damn thing, and making PAL support work is pretty low down the list of things that need fixing, even if it would be an easy enough fix. Anybody is welcome to improve it btw. I don't really plan on looking at it again but right now it's not even a remotely accurate representation of the 32x.

Multipass #59791 03/07/10 06:57 PM
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Thanks Haze for your reply, i dont know, i asked them wink wink

Multipass #59793 03/07/10 07:29 PM
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notice that, while Haze is perfectly correct about the current issues (i.e. go and find another emu if you want to play 32x), you can still pass through that screen by pressing TAB, selecting the PAL region in the Driver Configuration menu and restarting the emulation with Shift+F3 (the same holds true if you want to play non-US Virtua Racing in the megadrive+SVP system).

Haze #59800 03/07/10 09:12 PM
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Originally Posted By Haze
From what I'm told (and what other emulators do) anything reading the FIFO buffers is meant to stall until it has data to read, MAME/MESS simply can't do this, you have to return something from a read.


You can do something like that in MESS. xor100.c uses a scheme where doing a read from a certain port stalls the Z80 by clearing the RDY line, and when a floppy IRQ/DRQ happens, the RDY line is asserted and the Z80 continues.

Curt Coder #59801 03/07/10 09:37 PM
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Originally Posted By Curt Coder
Originally Posted By Haze
From what I'm told (and what other emulators do) anything reading the FIFO buffers is meant to stall until it has data to read, MAME/MESS simply can't do this, you have to return something from a read.


You can do something like that in MESS. xor100.c uses a scheme where doing a read from a certain port stalls the Z80 by clearing the RDY line, and when a floppy IRQ/DRQ happens, the RDY line is asserted and the Z80 continues.


I fail to see how you can do it without special work in the CPU core. Even if you call a function to halt / stall the CPU from within the read handler you still have to return something. The game expects nothing to be returned until there is something to be returned.

Due to the nature of code execution (MAME is running a single thread) there is no way out of the read handler unless you return something, and the opcode must be full executed. The HALT can/will only take effect AFTER the current opcode. This isn't suitable, it must halt mid-opcode for it to work.

I fail to see how it can possibly work, even if some other driver claims to do it, unless there is very special handling in the CPU core and all read/write parts of each opcode are entirely separate. Even a simple hack to step back the opcode wouldn't be suitable, as things like the write part of a read/write operation shouldn't happen until the SH2 is unstalled and able to read the data.

That is if I'm to believe what I'm told about how it works.


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