Zilog Z80 discontinued after nearly 50 years

[Thomas Okken]

(06-01-2024 08:18 PM)Steve Simpkin Wrote:  “The 6502 was never, and I mean never, talked about as being a CPU (Central Processing Unit) for a computing system,” says Bill Mensch. “The instruction set was picked for controllers. In other words, the controller instruction set was designed specifically to compete with the Intel 4040, which was a two- or three-chip-system solution.”

Now I'm curious as to what the ramifications of "designing it for a computing system" would have been. Because I've done 6502 assembly language programming, on the Commodore PET and on the C64, and I found the experience delightfully easy. I certainly never experienced the kind of frustration I'd expect from using a CPU that was being used for something it wasn't designed for. On the contrary, the 6502 instruction set seems really general-purpose, with the crucial bit of cleverness being a good set of addressing modes, and avoiding the complexity of a large set of registers by off-loading them to page 0 of main RAM. A well-rounded design, so how would they have done it differently if they had been designing a CPU specifically for computers?