Once you have enough transistors on a board, though, one of the first layers of abstraction that arises is the Arithmetic Logic Unit ... perform seven functions: ADD, SUB, XOR, XNOR, AND, OR ...

So what’s the discrete logic aficionado to do if they want to stand out from the pack? Perhaps this CPU-less computer with a single NOR-gate instead of an arithmetic ... couple of add-on cards ...

An earlier logic chip used as a building block for ... etc.). They included inputs and outputs for borrow and carry bits (addition and subtraction require carrying to and borrowing from the ...