DigiFlop

The Lego bricks combinational logic is assembled from.

VLSI Concept · Fundamentals
Adders, Muxes & Decoders
The Lego bricks combinational logic is assembled from.

A handful of small combinational building blocks show up everywhere: a half/full adder adds bits with a carry; a multiplexer (mux) selects one of several inputs based on a select line; a decoder turns a binary code into a one-hot set of outputs. Nearly every larger datapath is these blocks wired together at scale.

Full addersum = A⊕B⊕Cin, carry = majority(A,B,Cin).
MuxThe "if/else" of hardware — the select line literally chooses which input reaches the output.
Why it mattersAn N-bit ripple-carry adder is just N full adders chained together — complexity from repetition, not new ideas.
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