Compressor3 constructor
Construct a 3-input column compressor (full-adder)
Implementation
Compressor3(super.compressBits, {super.name = 'compressor_3'}) {
sum <= compressBits.xor();
carry <=
mux(compressBits[0], compressBits.slice(2, 1).or(),
compressBits.slice(2, 1).and());
}