SIGNAL TAGGING DURING SIMULATION

Approaches for simulating a circuit design. A block diagram of the circuit design is displayed. Each block has at least one input and at least one output, and at least one of the input or output of each block is connected to another block. Simulation data are input to a simulation model of the circuit design. During simulation of each of a plurality of the sub-circuits with the simulation model, an output data value is determined from one or more input data values to the simulated sub-circuit. Concurrent with determining the output data value, an output tag value corresponding to the output data value is determined. Concurrent with output of the output data value from the simulated sub-circuit, each output tag value is displayed proximate an output signal line from the block corresponding to the sub-circuit.