To write RTL code that gives the best possible QoR (quality of results) during datapath synthesis, it is important to understand what datapath functionality current synthesizers can efficiently implement, how the datapath synthesis flow works, and how coding can influence the effectiveness of datapath synthesis. This document summarizes coding guidelines addressing the synthesis of datapaths. Two classes of guidelines are distinguished: (1) Guidelines that help achieve functional correctness and the intended behavior of arithmetic expressions in RTL code and (2) Guidelines that help datapath synthesis to achieve the best possible QoR.