Michael J. Mahon wrote:
John Selck wrote:Huh? They did move forward. 6510 -> 8500 -> 8502. And also, I don't think it's any kind of problem for Commodore to use customized CPUs since they owned MOS, the owners and producers of 6502 tech back then :)And these new processors preserved the undefined opcode behavior? If so, they are almost certainly *not* new processor designs.
Same opcodes but faster clockspeed. Also, CBM switched from NMOS to HMOS.
3) Slow-as-hell 8 Bit platforms don't have a proper abstraction layer for any of their hardware, no matter if sound, graphics, timers, ports or CPU.Nonsense. The "abstraction" we are discussing is the published documentation for the processor/system. What it documents is the abstraction that future implementations will preserve. What it doesn't document will generally not be preserved.
What about the bugs in the decimal mode? They were fixed on later processor designs, this also renders the CPUs incompatible for some programs.