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-   -   Possible route to increase PPC RAM. (https://eab.abime.net/showthread.php?t=83313)

headkase 02 July 2016 06:16

Possible route to increase PPC RAM.
 
I really think this can be done. Everyone is going down the path of "Hyperion should add support for using Z3 RAM as fast RAM." Bollocks. Think about the Blizzard and Cyberstorm PPC expansions. They come with different amounts of memory even within the exact-same-for-the-rest of the parts. Then AmigaOS 4 itself supports different amounts of memory. Here is where I think a fruitful approach is to increasing the amount of fast RAM for PPC emulation: edit the Blizzard or Cyberstorm ROMs and get them to use more memory at the very lowest level. I don't think the limit is in the operating system, I think the ROMs only look for a (known) maximum amount of RAM and stop there. If the ROM would configure more RAM I think that OS 4.x would just use it.

Diz_57 02 July 2016 06:31

Surely someone would have already done this if the limit really wasnt in the os

headkase 02 July 2016 06:47

What made me think this: in the install guide I did for A1200/Blizzard, I overrode the ppc_model to basically put the Cyberstorm PPC processor into the Blizzard hardware configuration. The Cyberstorm is "limited" to 128MB of RAM, yet that processor configuration has no trouble running with the Blizzard 256MB of RAM. It would seem to be silly for a hard-coded RAM limit to be in the upper-layers, in the OS, especially since there are so many variations of possible amounts of RAM. This leads me to firmly believe that OS4.x just uses the configured RAM from the lower-level: the PPC expansion logic. And then in that expansion logic I think it is a reasonable assumption to make that the RAM "limits" come from the physical hardware layouts and not from address problems. The ROMs came from real hardware that could only hold so much RAM so they stopped at that amount of RAM. If the ROMs could be patched to configure more RAM at that lower-level then I think the higher-levels would just inherit it.

headkase 02 July 2016 07:51

Are there any other PPC operating systems that can be used in WinUAE? A test to determine if the above is true is to boot one of those operating systems with the accelerator memory set above 256MB and see if it gets it or not.

Diz_57 02 July 2016 15:44

How does a different os prove anything? the limit can still be hard coded into os4!

kamelito 03 July 2016 00:18

Alain (Wazp3D author) already patched the rom and it didn't worked.
Kamelito

DarrenHD 10 July 2016 05:06

Quote:

Originally Posted by headkase (Post 1099303)
I really think this can be done. Everyone is going down the path of "Hyperion should add support for using Z3 RAM as fast RAM." Bollocks. Think about the Blizzard and Cyberstorm PPC expansions. They come with different amounts of memory even within the exact-same-for-the-rest of the parts. Then AmigaOS 4 itself supports different amounts of memory. Here is where I think a fruitful approach is to increasing the amount of fast RAM for PPC emulation: edit the Blizzard or Cyberstorm ROMs and get them to use more memory at the very lowest level. I don't think the limit is in the operating system, I think the ROMs only look for a (known) maximum amount of RAM and stop there. If the ROM would configure more RAM I think that OS 4.x would just use it.

Unfortunately it won't work. OS4 looks at specific memory regions and those are specifically defined, so it just won't work. All I will say is...patience is a virtue :)

antiriad76 11 July 2016 05:44

I believe the request has already been made to increase the supported Z3 RAM on the Hyperion Website.

The was a misconception that the Z3 in emulation is as slow as the original Amiga Z3 RAM.

http://forum.hyperion-entertainment....hp?f=36&t=3331


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