Network code

Technical discussion for those interested in Supermodel development and Model 3 reverse engineering. Prospective contributors welcome.
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Re: Network code

Postby Jiterdomer » Thu Jul 11, 2019 8:52 am

Does it tend to hang like Supermodel did?
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Re: Network code

Postby Ian » Thu Jul 11, 2019 9:01 am

To really solve this network thing ..
If someone was able to actually capture the network data between 2 machines, that would really go a long way to working out the missing pieces
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Re: Network code

Postby Hydreigon233 » Thu Jul 11, 2019 1:14 pm

Jiterdomer wrote:Does it tend to hang like Supermodel did?

Yes...mainly because I didn't know Supermodel's network can hang (probably if using a different build or not setting the emulator to single core).
Ian wrote:To really solve this network thing ..
If someone was able to actually capture the network data between 2 machines, that would really go a long way to working out the missing pieces
The question is how to actually capture the network data and if it requires a sophisticated setup? Model 1 data exchange was already "difficult enough" to figure out.
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Re: Network code

Postby Bart » Thu Jul 11, 2019 2:38 pm

Would also be helpful to know what sort of network ASIC was used. That would at least allow the 68K code to be reverse engineered and understood. IIRC, Model 1 used some Fujitsu part. Does the 68K code read out any ID codes from the ASIC? If data sheets for modems from that time period could still be gathered, that sort of thing would go a long way toward identifying the device.
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Re: Network code

Postby Hydreigon233 » Thu Jul 11, 2019 7:31 pm

Bart wrote:Would also be helpful to know what sort of network ASIC was used. That would at least allow the 68K code to be reverse engineered and understood. IIRC, Model 1 used some Fujitsu part. Does the 68K code read out any ID codes from the ASIC? If data sheets for modems from that time period could still be gathered, that sort of thing would go a long way toward identifying the device.
My predicament is there could be some important code from those Sega customs. They are the also the same across the Hikaru and Naomi comm boards too.
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Re: Network code

Postby Jiterdomer » Thu Jul 11, 2019 8:33 pm

Hydreigon, have you used to CPU timing stuff for arcade hardwares that will explain why Scud Race and Daytona 2's link feature made the emulator slow even on high-end PCs.
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Re: Network code

Postby Ian » Fri Jul 12, 2019 3:06 am

From what I understand from Sailorsat and spindizzi is the model2 and model3 network code is very very similar
Model3 uses a different CPU tho but essentially it works the same.

I tried emulating the actual real3d pro-1000 standalone, and got pretty far, but not far enough to actually get it running. If i could have logged the actual traffic between the devices would have gone a long way to getting it working
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Re: Network code

Postby Hydreigon233 » Fri Jul 12, 2019 7:41 am

Jiterdomer wrote:Hydreigon, have you used to CPU timing stuff for arcade hardwares that will explain why Scud Race and Daytona 2's link feature made the emulator slow even on high-end PCs.
No. I am sadly not familiar with this stuff but wish to know. Can you send me a good example sometime?
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Re: Network code

Postby Bart » Fri Jul 12, 2019 9:47 pm

With some work it should be possible to reverse engineer the high level PowerPC/network board protocol but there may be differences from game to game.

The other approach is to try emulating the modem. Nik mostly figured out where the various packet input and output buffers were and generally how to manage them but noted that numerous IRQs were being used by the 68k and that at least one of them had to be fired regularly. Knowing the modem ASIC would go a long way toward making the 68k network program comprehensible. While the high level protocol may be virtually identical to Model 1 and 2, the actual modem is likely completely different. At first glance, I did not think that the part used in Model 1 (by Fujitsu) looked like what Model 3 uses (I looked at what possible interrupt signals the chip could generate).

The part may be labeled as a Sega custom ASIC but I’m certain it is actually an off-the-shelf design from the time period.
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Re: Network code

Postby Jiterdomer » Fri Jul 12, 2019 11:09 pm

Hydreigon233 wrote:
Jiterdomer wrote:Hydreigon, have you used to CPU timing stuff for arcade hardwares that will explain why Scud Race and Daytona 2's link feature made the emulator slow even on high-end PCs.
No. I am sadly not familiar with this stuff but wish to know. Can you send me a good example sometime?


Take Step 2.1 games for example, LA Machineguns and Harley had graphic bugs related to timing where instead of showing screen going black or white, it shows garbage graphics for half a second.
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