It is often said the 6502 has 256 registers - being all the bytes in zero page (assuming 256 bytes in zero page exist, the Atari just had 128). It's a fair lea

It is often said the 6502 has 256 registers - being all the bytes in zero page (assuming 256 bytes in zero page exist, the Atari just had 128). It's a fair leap - all of the "indirect" instructions that do access-through-pointer stuff are zero page and would be register-oriented in most other architectures. Plus loading and storing stuff to zero page consumes the same cycles as a register (2), zero page is not slower than registers generally. You want something really icky try to make sense of Fairchild F8 with it's 64 internal bytes of "scratchpad" RAM which are kinda halfway between registers and RAM due to the weirdness of the F8 architecture.