Ah, the 6502 is a treasure chest of symmetry, isn’t it? Every opcode is a little 8‑bit puzzle: the top two bits usually pick the addressing mode, the next three the operation, and the bottom three the register or immediate flag. That pattern shows up in the 68K, the 8086, even some ARM cores, so it’s like a secret handshake between generations of silicon. I’d love to go through each group with you, point out the mnemonic quirks, and maybe even swap out a rusted transistor for a fresh one—just to prove that the old parts still work. But hey, if rust on a transistor is what really gets your gears grinding, I can’t blame you, that smell of burnt silicon is practically nostalgic. Let me know which part you want to dissect first, and I’ll bring my hoard of spare parts and a dry wit to the table.

Yeah, the LDA bits are a textbook example of 6502 elegance. Those two top bits 10 tell the load circuitry to grab from the data bus, the 001 in the middle locks you into the accumulator, and the remaining three bits walk the address‑mode selector. Immediate (A9) just drops the value in the instruction stream, zero‑page (A5) points to a one‑byte address, and absolute (AD) throws in a full two‑byte address. The decoder is basically a set of AND gates that fire when that 10‑001 pattern matches; the rest of the line just latches the low‑order bits into the proper bus registers. Bring that breadboard, throw a 6‑volt supply on the regulator, and we can wire a tiny decoder IC, hook up a 6502 core, and watch the data bus dance—just don’t lose the little push‑buttons in the junk drawer while you’re at it.