Register Transfer Level

In digital circuit design, register-transfer level (RTL) is a design abstraction which models a synchronous digital circuit in terms of the flow of digital signals (data) between hardware registers, and the logical operations performed on those signals. Register-transfer-level abstraction is used in hardware description languages (HDLs) like Verilog and VHDL to create high-level representations of a circuit, from which lower-level representations and ultimately actual wiring can be derived. Design at the RTL level is typical practice in modern digital design. Unlike in software compiler design, where the register-transfer level is an intermediate representation and at the lowest level, the RTL level is the usual input that circuit designers operate on. In fact, in circuit synthesis, an intermediate language between the input register transfer level representation and the target netlist is sometimes used. Unlike in netlist, constructs such as cells, functions, and multi-bit registers are available. Examples include FIRRTL and RTLIL. Transaction-level modeling is a higher level of electronic system design. A synchronous circuit consists of two kinds of elements: registers (Sequential logic) and combinational logic. Registers (usually implemented as D flip-flops) synchronize the circuit's operation to the edges of the clock signal, and are the only elements in the circuit that have memory properties. Combinational logic performs all the logical functions in the circuit and it typically consists of logic gates. For example, a very simple synchronous circuit is shown in the figure. The inverter is connected from the output, Q, of a register to the register's input, D, to create a circuit that changes its state on each rising edge of the clock, clk. In this circuit, the combinational logic consists of the inverter. When designing digital integrated circuits with a hardware description language (HDL), the designs are usually engineered at a higher level of abstraction than transistor level (logic families) or logic gate level.

Scalable Logic Rewriting Using Don’t Cares

Giovanni De Micheli, Alessandro Tempia Calvino

Logic rewriting is a powerful optimization technique that replaces small sections of a Boolean network with better implementations. Typically, exact synthesis is used to compute optimum replacement on-the-fly, with possible support for Boolean don't cares. ...

2024

Contemporary Logic Synthesis: with an Application to AQFP Circuit Optimization

Highly Parallel RTL Simulation

Scalable Logic Rewriting Using Don’t Cares

Contemporary Logic Synthesis: with an Application to AQFP Circuit Optimization

Highly Parallel RTL Simulation

Scalable Logic Rewriting Using Don’t Cares