Visibility enhancement for silicon debug

Several emerging Design-for-Debug (DFD) methodologies are addressing silicon debug by making internal signal values and other data observable. Most of these methodologies require the instrumentation of on-chip logic for extracting the internal register data from in situ silicon. Unfortunately, lack of visibility of the combinational network values impedes the ability to functionally debug the silicon part. Visibility enhancement techniques enable the virtual observation of combinational nodes with minimal computational overhead. These techniques also cover the register selection analysis for DFD and multi-level design abstraction correlation for viewing values at the register transfer level (RTL). Experimental results show that visibility enhancement techniques can leverage a small amount of extracted data to provide a high amount of computed combinational signal data. Visibility enhancement provides the needed connection between data obtained from the DFD logic and HDL simulation-related debug systems.