VPTERNLOG: A Deeper Insight into Ternary and Binary Operations

Like many, upon encountering VPTERNLOG, my initial reaction was to appreciate that \(\log_2(3) \approx 1.58\) is a notable reduction in depth, despite not frequently encountering super deep reductions in my code.

The Power of Ternary Operators

Upon reflection, a significant advantage emerges on smaller, reasonable scales: while a binary operator processes two values into one, a ternary operator processes three into one. In reduction scenarios, each binary operator application reduces the number of values by \(2 – 1 = 1\). Conversely, each ternary operator application reduces it by \(3 – 1 = 2\).

Efficiency and Performance

This means we require half as many ternary operations to reduce a given set of bitvectors compared to binary operations. Importantly, this efficiency doesn’t come at the cost of throughput or latency. The orthogonal nature of a lookup table further enhances its utility.

The verdict? VPTERNLOG proves to be a lightweight and efficient instruction, deserving of high praise.

Authored by Paul Khuong