Re: C64/128 Wolf and GS upgrade support

[Cameron Kaiser <cdkaiser@delete.these.four.words.concentric.net>]

supertimer@aol.com (Supertimer) writes:

>>     A significant GS upgrade is a tougher challenge than a significant
>>C64/128 upgrade. One thing seems fairly certain, the only way to sell GS
>>users on the idea of a major Speed/Memory upgrade (e.g. 20MHz/32MB) is
>>to include an SVGA Video upgrade on the same board. Do this plus permit
>>access to the OS and CBM or whoever makes the plug-in will have a
>>winner.

>Rubywand, the above statement appears to indicate that the C64/128
>accelerators can't access their OS.  From what I have read about these
>CMD accelerators, I have been led to believe that they function with
>all Commodore software.  I thought they had no restrictions and could
>be used like we GS users utilize TWGS or Zip GS accelerators.  I have
>read testimonials of phenomenal success under GEOS (their OS) and
>games of all sorts.  How well do these accelerators perform?

They can and do access the OS with no trouble. Not all software is compatible,
not because of any flaw in the device, but because some C64 software takes
advantage of defects in the NMOS logic of the 6510 (the so-called "undocumented
opcodes") that are either patched up in the CMOS 65816 or replaced by an
entirely new opcode. They perform exceptionally well and already software is
appearing to take advantage of them specifically.

To be sure, the 16MB memory ceiling is only available to programs running in
the 816's native mode. In emulation mode, the processor emulates the 6510,
bank-switching and all, and is limited to 64K. All pre-SCPU programs need to
run in emulation mode, which is why the processor powers up in that mode.

--
Cameron Kaiser
cdkaiser at concentric dot net (it hasn't helped the spam yet though)
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