Posted By
MMS
on 2020-04-06
02:01:00
 |  Re: C64portal.pl has started - and it's not only c64 :)
OFF
gerliczer,
actually here you are not corrent. Or in special circumstances you are not correct, in case of main use, then correct 
As visible in SVS Ultimate Map's last version, you can FORCE the C16 / Plus/4 into a mode where it is >200% of the original C64 speed, without HW modification (just by setting some register bits).
Certainly here you need to switch off the screen, but then you get exactly what was realised on C128 as FAST mode for calculations (2MHz CPU). If I am correct, maybe thr 8501 in this special mode is even faster than the 8502 at 2MHz.
(I believe some decompressors or fastloader used this or similar other mode)
So Plus/4 has a speacial mode 2x faster than the C64. You see nothing, but it exists
As we already speak
6502 had a variant was able to run at 4MHz. Maybe 65C02.
TED provide the clock for the 8501.
There is already a CPU repair kit from some guys (including MCeS) utilizing 65C02 CPU.
What if they would add a swichable frq doubler to the story?
http://www.circuit-finder.com/categories/digital/377/frequency-doubler-with-4011
Then the 65C02 (already lost it's full compatibility with 8501, eh) could be use a turbo speed the C16 with a proper heatsink. As it does not influence the RAM chips (handled by the TED) it could reach the speed of BBC Micro with it's fastest CPU card.
As Pigmy explained me several dosens years earlier, most of the jobs during the converted games need to be done at the border time.
The CPU is fastest here, you does not need to share the memory with TED, higher clock rate (given by the TED).
The software sprite (Tass Times), the SID FRQ emulation done by him here. I suppose by all programmers. If SW sprite or moving object update happens during screen area, the vibrations wiln happen.
So all these calculations have to fit into the border time to do not interfere/influence screen data and drawing.
What if the 264 CPU would may have 2x more calculation potential? What could be possible?
-Bigger SW sprites could be used?
-Higher sampling rate of SID emulation? or you can do something next to SID digi emu (as CPU now is almost 100% utilized)
-Real FLI? (change colors and luminance int every rasterline, not only at every second line (DFLI) ?
(AFAIK then Larry's first FLI slideshows would look great, as initially he forced the same mode as available on C64)
You know, I am just a dreamer, not an executor or a developer. Just have different ideas.
But it sounds logical, that double CPU power would open new possibilities on the 264 series, even with the currently available applications.
And at my amateur level it seems it does not need major redesign of an available board, but just adding few cheap components on the existing board (though it also means redesign, but only small components, they may fit).
Certainly it means new incompatibilities or just variations (next to SID card, 1551/1541/SD), but the CPU version could be identified from SW and may or may not utilize the additional CPU power (eg single or double precision SID digi sampling rate).
Or I am completely wrong? Would it kill the memory handling or the screen?
HW experts, please help me here
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