Comment Re:Megahertz myth and the 6502 (Score 1) 179
THe 6502 was an amazing processor. the Apple II was also a 6502. Unlike it's near contemporaries, the 8086 and Z-80 (and 6800), the instruction set was reduced. It had only 2 data registers (A,B) and two 8 bit address registers ( X Y) and fewer complicated ways to branch. Instead it effectively memory mapped the registers by using instructions like, offset Y by A, treat that as an address and get the byte at that location. Because it could do all that in one clock cycle, This effectively gave it 256 memory mapped registers. It also didn't have separate input lines for perifprials, and instead memory mapped those.
Actually the 6502 only had one accumulator, the A register. The 6809 had A and B. It is correct that the 6502 had very nice addressing modes. Zero page addresses acted more like machine registers. One commonly used addressing mode was z-page indirect indexed by Y. Two consecutive locations on z-page acted like a 16 bit pointer and register. Either that could be incremented OR Y could be incremented. So a block move of 1 256 byte page was easy.
I don't think I *ever* used ($23,X) where X selects the z-page locs ("register pair") to use as a pointer.
At one time I had an Apple 2+ with a hardware accelerator board which ran at 3 MHz instead of the standard 1 MHz. For many tasks, my fast 2+ outran a comterporary PC-AT machine. For word processing, the Apple was much more responsive.
The conventional wisdom at the time was that the 65xx was clock for clock 4x more powerful. 3x4 effectively was 12 MHz which was faster than an AT. (Yes I'm ignoring memory and disk....).