TROLOZY wrote:
now x86 is most used cpu type in home PC, Workstation, Server, and etc,
if 6502 and CPU based on it, was more popular choice in 80's . Why can't 6502 grow?
A few thoughts on this area...
First, I think it's very much the exception that x86 has had the life it has. Most CPUs are replaced by something incompatible, which usually does much better or much worse in the market. Moto did pretty well, in fact, with 6809 and then 68000. But 68000 was not an endpoint: 88000 and powerpc came after, IIRC. And these are not nearly so compatible as the x86 line - compatibility was not a goal. Zilog tried similarly but got very little traction with their successor ideas, the not-z80-compatible
Z8000 and the Z8000-compatible
Z80000.
Second, Intel tried several times to do the normal thing, to kill x86 and make a successor. But it was too much of a monster. I can think of
i432/8800,
i960,
i860,
Itanium.
So, if 6502 had had an owner interested in higher performance implementations and architectural extensions, we might have seen different developments - but it still would have been unusual. Both Commodore and Atari, in rather different ways, went to 68000 for their successor lines. Apple dallied with '816 but again went to 68000 (and ARM, and PowerPC, but that's all later.) Acorn dallied with '816, tried National Semiconductor's 32000 line, and then made ARM. That's interesting, because it was a move which said a new architecture was a better way to proceed than an improved implementation: nothing would have prevented Acorn from trying to make an improved 6502, but they judged that a simple pipelined machine with a wide memory interface and regular instructions was the way to go.
Finally, of interest in this discussion, a mid-'85 project idea within Apple which didn't fly but could be compared to Acorn's idea: