In this paper we formally define an enhanced RTL semantics. This is intended to elevate the RTL design abstraction level and help bridge the HDL semantic gap among synthesis, simulation and formal verification tools. We define the enhanced semantics based on a new RTL++ language that supports pipelined operations using a new pipelined register variable concept. The execution semantics of RTL++ is specified in a structural operational semantics style aimed to form the basis for related simulation and formal verification algorithm development. A RFSM model is defined to support natively the synthesis semantics of RTL++. We also present an example of extending SystemC to support the notion of pipelined register variable.