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Once upon a time, Jon Bentley wrote one of his Programming Pearls (IIRC) about two string reversal algorithms; both were Big-O identical, but one finished in seconds on a sufficiently large string and he killed the other after several minutes. The punchline was that the second was exactly pessimal with regard to paged VM.

This wasn't a new realization, even in 2010.

The neat thing is that Bentley's string could probably be reversed in cache today.



> The neat thing is that Bentley's string could probably be reversed in cache today.

Yeah, those big Zen 2 Epyc CPUs have 256 Megabytes of L3 cache. Now. That's more than like, either of my first two computers had in RAM.


Zen 2 EPYC CPUs have more than a third as much storage in their register file as my first computer had RAM.


Are you including the shadow registers? I suspect EPYCs actually have quite a bit more.

Edit. 8 byte registers * 168 total regs = 1344 bytes, so a) you were and b) guessing it was a VIC20?


I was working off a figure of 180 in the Zen 2 core for 1440. It was the TRS-80 Model III with 4K, though I did acquire a VIC-20 a little later too.




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