Arlet wrote:
e2020 wrote:
why aren't there 6502 running @ 3Ghz (3000 mhz) ?
please answer hereWhat's the market for such a thing ? No good C compiler, small memory, and no cache. If you need high performance, there are plenty of CPUs already available.
The basic 65xx design at 200 MHz (as found in custom ASICs) has greater throughput than an Intel architecture MPU at the same clock rate, especially when interrupt latency is considered. So it could be argued that the market isn't there because the 200 MHz iteration performs more than adequately in its intended task. I suspect that if a 65xx application were developed where higher performance was required someone would figure out how to make it go faster.
Something Mr. e2020 should think about is just what is getting accomplished at 3000 MHz. While the MPU core may be running that fast, the buses and memory subsystem are not. A contributing factor to the 65xx family's efficiency is the fact that the address and data buses are synchronous to the MPU clock, not a submultiple of it. If an AMD Athlon II system running at 3000 MHz were slowed down to 200 MHz, with a corresponding reduction in bus and memory subsystem speed, it wouldn't produce the throughput of a 65xx system running at the same clock rate.
Regarding memory, the 16 MB limit of the 65C816 may seem terribly small to some. However, I need to remind you that it wasn't all that long ago when 16 MB of memory was luxurious. My first UNIX box (c. 1988) ran on 2 MB of RAM and had little difficulty in supporting 16 simultaneous users (albiet with a fair amount of disk thrashing). I will say that it noticeably speeded up when I added another 2 MB to it.
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When I built my new AMD 486DX100 box in 1994, I started with 8 MB of RAM and it ran fine. So capacious memory in itself is not necessarily a particular advantage unless a system fully utilizes it.
As for the C compiler, there are several good ones for the 65xx family. WDC's own ProSDK has an excellent C compiler that is tailor-made for emitting efficient 65C816 native mode code. While ProSDK is pricey, its cost to a professional developer would not be an issue.