Topic summary
MOS 6502
Extracted from the Wikipedia article MOS Technology 6502.
Programmer's model
Like most simple CPUs of the era, the dynamic NMOS 6502 chip is not sequenced by microcode but decoded directly using a dedicated PLA. The decoder occupied about 15% of the chip area. This compares to later microcode-based designs like the Motorola 68000, where the microcode ROM and decoder engine represented about a third of the gates in the system.