Definitely the same, at the level Steve and I were talking about. The 6502 has instructions that manipulate registers and memory, logical and arithmetic operati

Definitely the same, at the level Steve and I were talking about. The 6502 has instructions that manipulate registers and memory, logical and arithmetic operations, branches and calls, status flags, and so forth. Just like all the "mainframe" CPUs I'd been programming. The word size is different, the special areas of memory are different, it has different opcodes, and so on. But any competent machine language programmer of the day - regardless of which CPUs they'd programmed on before - would have had no trouble understanding this: http://www.obelisk.me.uk/6502/instructions.html http://www.obelisk.me.uk/6502/instructions.html That's what Steve didn't understand at the time. Not being a programmer himself, he didn't know how familiar all this would look to any machine language programmer.