Over the course of a few posts, I will be constructing an NES emulator that will allow you to play NES ROMs. Today’s post is the first in this series, where I will be walking through the process of emulating the CPU the NES used, the MOS 6502. STRUCTURE The 6502 has 6 primary registers we need to emulate in our program. The A register is the accumulator, which is 1 byte long The X register is an index register, which is also 1 byte long The Y register is another index register, also 1 byte long