Todays test program: load values into the A and B registers, add (or subtract) them and loop.
I've got the jump working but the ALU ops are not so pretty. It's inverting each bit of A if the bit in B is set. The circuit for the ALU is all standard gates, and I'd be surprised if there's any bugs in there given the rest of the simulator is working so well.
So it's probably a schematic issue, and one which will take a bit of debugging.
