[theamk]

That Z80 code is not the equivalent of the modern code though, is it?

for example your modern code mentions 64KB lookup table.. no way you can port this to Z80 which has 64KB of address space total, shared for input, output, cache and code.

So what do those timings mean? Are those just a made up numbers for the sake of narrative?

[michalpleban]

Input and output are in a separate address space on the Z80. It's on the 6502 where they share space with code and data.

[theamk]

what do you mean?

Memory and i/o ports are in separate address spaces in Z80, but for use cases described in post ("dot product for 1536-bit vectors") i/o port space does not matter, it's all memory - and there is just a single address space there.

(Granted, some Z80-based systems had funky paging setup, but author makes no mention of those, they just say generic Z80 - and that means total 64KB for code, input data, cache and output data)