>>>>> "gb" == g baltissen <email@example.com> writes: gb> Hallo allemaal, I have two question that possibly fits in this gb> discussion: The SCPU uses its own memory to maintain maximum gb> speed. But the the content has to be copied in some or another way gb> to the original memory - how is this done? Probably DMA? Seems reasonable. gb> - what range is copied and how does the mechanism know? There are "optimization" registers in the SuperCPU that determines what ranges are copied. The default in SuperCPU V1 is to mirror every- thing, and the default in V2 is to mirror everything but page 0 and 1. So unless a program wants to display $0000-$01ff, it'll run without problems. Of course, this slows down all memory writes to 1 MHz, so a SuperCPU optimized/aware program uses the optimization registers to only mirror the parts of memory that will actually be used for memory, such as $4000-$7fff. gb> We already discussed replacing a non 6502 CPU by 6502 + Hardware. gb> I prooved it can be done. Now to find a way to be able to use fast gb> memory. If you have a way of intercepting write cycles to memory it shouldn't be too hard to implement mirroring. This way the CPU will read at X MHz and write a 1 MHz, running at full speed most of the time. gb> This triggered another question: the 65816 can run on 20 MHz. The gb> SIMMs SCPU uses ar mostly of the 70 ns type. 20 Mhz means 25 ns gb> cycles. How does that fit? Wait states. I don't have the numbers with me, but access to SuperRAM can take several cycles. -- ___ . . . . . + . . o _|___|_ + . + . + . . Per Olofsson, konstnär o-o . . . o + MagerValp@cling.gu.se - + + . http://www.cling.gu.se/~cl3polof/ - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail firstname.lastname@example.org.
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