Sega Saturn Core Update

cathrynmataga
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Re: Sega Saturn Core Update

Unread post by cathrynmataga »

Woah, did this guy build the CPU and the graphics chips both from scratch? Saturn has a pretty oddball CPU.
zakk4223
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Re: Sega Saturn Core Update

Unread post by zakk4223 »

douglasamcintosh wrote: Tue Sep 14, 2021 4:48 pm When (if) this core is released will it accept CHD files like most of the other disc based consoles?
CHD and BIN/CUE support is implemented entirely within Main_MiSTer, so it's basically independent of the core. There's a bit of 'glue' in Main that's specific to each core (since they all have some quirks) but the majority of the heavy lifting is non-core specific.

Assuming this core is implemented like other CD based cores, if the initial release doesn't include CHD support I'll add it like I did for the current CD-based cores.
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jdeberhart
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Re: Sega Saturn Core Update

Unread post by jdeberhart »

cathrynmataga wrote: Tue Sep 14, 2021 5:00 pm Woah, did this guy build the CPU and the graphics chips both from scratch? Saturn has a pretty oddball CPU.
All of the CPUs in the Saturn are normal CPUs: it uses a pair of Hitachi SH-2s, an SH-1, and a 68000. Maybe you're thinking about the VDPs? Most machines of this and previous generations used custom chips for the graphics, but the CPUs are all normal parts that are used in many other devices.
mic_
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Re: Sega Saturn Core Update

Unread post by mic_ »

The SH family isn't all that common though - nothing like the M68k. So I could well imagine that srg wrote his own SH-1 and SH-2 implementations. Fortunately they have pretty small instruction sets, so as far as processors go, those should be pretty easy to implement. At least that's my experience from writing software emulators, though I don't know how well that carries over to FPGA development.
throAU
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Re: Sega Saturn Core Update

Unread post by throAU »

mic_ wrote: Wed Sep 15, 2021 8:10 am The SH family isn't all that common though - nothing like the M68k. So I could well imagine that srg wrote his own SH-1 and SH-2 implementations. Fortunately they have pretty small instruction sets, so as far as processors go, those should be pretty easy to implement. At least that's my experience from writing software emulators, though I don't know how well that carries over to FPGA development.
The SH-2 has an open source implementation now (J-Core) as Hitachi let the patents expire.

https://j-core.org/

The 68000 has already been done

The VDP1 and VDP2 would definitely need re-implementing from scratch
srg320
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Re: Sega Saturn Core Update

Unread post by srg320 »

throAU wrote: Wed Sep 15, 2021 9:38 am
mic_ wrote: Wed Sep 15, 2021 8:10 am The SH family isn't all that common though - nothing like the M68k. So I could well imagine that srg wrote his own SH-1 and SH-2 implementations. Fortunately they have pretty small instruction sets, so as far as processors go, those should be pretty easy to implement. At least that's my experience from writing software emulators, though I don't know how well that carries over to FPGA development.
The SH-2 has an open source implementation now (J-Core) as Hitachi let the patents expire.

https://j-core.org/

The 68000 has already been done

The VDP1 and VDP2 would definitely need re-implementing from scratch
SH1/SH2 is not only a SuperH processor core, but also contains some peripheral modules.
Снимок.PNG
Снимок.PNG (33.08 KiB) Viewed 1623 times
J-Core does not match me because it has separate buses for instructions and data as well as the caches, also does not contain most of the peripheral modules.

For 68000 I use fx68k core of course.
Jeruro
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Re: Sega Saturn Core Update

Unread post by Jeruro »

Thanks for the info!
Mr. Encyclopedia
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Re: Sega Saturn Core Update

Unread post by Mr. Encyclopedia »

The Cyclone V in the De10-Nano has 41,910 ALMS in 110k LEs, so according to srg's chart the SH1/SH2 chips seem to take up about one fourth of the FPGA capacity.

Also worth pointing out that the 32X and CPS-3 also use SH-2 processors so this hard work is paving the way for those cores in the future.
retro
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Re: Sega Saturn Core Update

Unread post by retro »

Mr. Encyclopedia wrote: Wed Sep 15, 2021 6:57 pm Also worth pointing out that the 32X and CPS-3 also use SH-2 processors so this hard work is paving the way for those cores in the future.
Did not know that! :)

It would be great to see CPS3 reproduced in MiSTer
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madmax
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Re: Sega Saturn Core Update

Unread post by madmax »

I hope we ll see SF3.3 CPS3 for the MiSTer.
PikWik
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Re: Sega Saturn Core Update

Unread post by PikWik »

i would also like to see CPS3 on the MiSTer
the_importer
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Re: Sega Saturn Core Update

Unread post by the_importer »

It would be nice, but I would much prefer that other systems being prioritised since the Dreamcast got 5/6 of the CPS-3 games.
Neocaron
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Re: Sega Saturn Core Update

Unread post by Neocaron »

the_importer wrote: Sat Sep 18, 2021 11:43 pm It would be nice, but I would much prefer that other systems being prioritised since the Dreamcast got 5/6 of the CPS-3 games.
It's not like there is anyway to port the Dreamcast on the Mister though :lol: ... Not in full FPGA way anyway.
the_importer
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Re: Sega Saturn Core Update

Unread post by the_importer »

Neocaron wrote: Sun Sep 19, 2021 12:35 am
the_importer wrote: Sat Sep 18, 2021 11:43 pm It would be nice, but I would much prefer that other systems being prioritised since the Dreamcast got 5/6 of the CPS-3 games.
It's not like there is anyway to port the Dreamcast on the Mister though :lol: ... Not in full FPGA way anyway.
Doubt anyone in this community doesn't own a Dreamcast.
Kannibal
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Re: Sega Saturn Core Update

Unread post by Kannibal »

Would the Sega Saturn core be interchangeable with the Sega ST-V games?
[all assuming development goes as planned of course]
Neocaron
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Re: Sega Saturn Core Update

Unread post by Neocaron »

the_importer wrote: Sun Sep 19, 2021 1:40 am
Neocaron wrote: Sun Sep 19, 2021 12:35 am
the_importer wrote: Sat Sep 18, 2021 11:43 pm It would be nice, but I would much prefer that other systems being prioritised since the Dreamcast got 5/6 of the CPS-3 games.
It's not like there is anyway to port the Dreamcast on the Mister though :lol: ... Not in full FPGA way anyway.
Doubt anyone in this community doesn't own a Dreamcast.
I have a used one actually XD
Too much crazy taxi and soul calibur turned it into a very tired grandma. It goes back to the idea that hardware fails and dies. Especially that gen.
The idea behind FPGA is also to preserve forever the fonctional blueprint of a said hardware. At the same time it's probably close to imposible to create an FPGA implementation of the Dreamcast and up even with all the space in the world... at least in a time where it would make sense. Emulation is probably the only way to go from there.
the_importer
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Re: Sega Saturn Core Update

Unread post by the_importer »

Neocaron wrote: Sun Sep 19, 2021 4:05 am
the_importer wrote: Sun Sep 19, 2021 1:40 am
Neocaron wrote: Sun Sep 19, 2021 12:35 am

It's not like there is anyway to port the Dreamcast on the Mister though :lol: ... Not in full FPGA way anyway.
Doubt anyone in this community doesn't own a Dreamcast.
I have a used one actually XD
Too much crazy taxi and soul calibur turned it into a very tired grandma. It goes back to the idea that hardware fails and dies. Especially that gen.
The idea behind FPGA is also to preserve forever the fonctional blueprint of a said hardware. At the same time it's probably close to imposible to create an FPGA implementation of the Dreamcast and up even with all the space in the world... at least in a time where it would make sense. Emulation is probably the only way to go from there.
There's more to the MiSTer in terms of FPGA to preserve game. An ODE does have FPGA in it and what do you know, the Dreamcast happens to have a few ODE's at its disposal including one that's been cloned the easily obtainable on Amazon.
ExCyber
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Re: Sega Saturn Core Update

Unread post by ExCyber »

Kannibal wrote: Sun Sep 19, 2021 2:21 am Would the Sega Saturn core be interchangeable with the Sega ST-V games?
[all assuming development goes as planned of course]
ST-V has an extra I/O chip to handle the standard player/coin inputs rather than routing those through SMPC, so it's not just a matter of loading the right ROMs into a Saturn core. That being said, the chip in question seems pretty simple, so a developer could probably deal with it after higher-priority stuff is done. Some games have protection chips or custom controllers, which would complicate things.
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