CPU / GPU emulation complexity

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omarsis81
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CPU / GPU emulation complexity

Post by omarsis81 »

Just curious… does cpu / gpu emulation complexity depend on how many transistors the chip has? Or I’m just talking nonsense?
I’m reading that the Pentium II (Klamath or Deschutes) has 7,500,000 transistors and the K6-III, the staggering amount of 21,400,000 transistors. So… is the K6-III emulation much more difficult to emulate than the Pentium II?
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SarahWalker
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Re: CPU / GPU emulation complexity

Post by SarahWalker »

You have to subtract the number of transistors used for memory, as they don't count towards complexity! A Pentium II has 32kB cache, which, assuming 6 transistors per byte (standard for SRAM) and with a bit of rounding to account for any tag RAM, comes to about 2 million transistors, leaving about 5.5 million of logic. The K6-III has 64kB L1 cache + 20kB predecode (attached to L1 code cache) + 256kB L2 cache = 340 kB, which comes to ~16 million transistors, do a bit of rounding and I think the K6 core is about 4-4.5 million transistors.

This gives you a rough idea of chip complexity, but this doesn't necessarily translate into emulation complexity. As it happens though, the Pentium II is probably harder to emulate accurately than the K6-III, so it works okay for this example...
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omarsis81
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Re: CPU / GPU emulation complexity

Post by omarsis81 »

Thanks for your words of wisdom. It's always a pleasure to read your posts!
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