Using advanced logging techniques to debug & test SystemVerilog HDL code

By Bindesh Patel and Amanda Hsiao, SpringSoft US.
Embedded.com (05/12/09, 07:08:00 PM EDT)

SystemVerilog provides an advantage in addressing the verification complexity challenge—not simply as a new language for describing complex structures, but as a platform for driving a more efficient, realistic test of the design. It is no surprise then that the adoption of the language for verification purposes has been rapid.

However, there is a gap when it comes to the debug and analysis of SystemVerilog testbench code. The accepted "dumpvars"-based techniques are not practical for the softwarelike object-oriented testbench code, and their benefits in this realm are also questionable.

But, at the end of the day, engineers do need to know what the testbench is doing at any given point in time. Thus far, engineers have been forced to revert to low-level, text-based message logging and subsequent manual analysis of the resulting text log files.

Logging—the process of recording history—has been widely used in systems and software environments. And most SystemVerilog libraries used today provide some built-in utilities for logging information from the testbench to low-level text files that can be analyzed after simulation.

Engineers then manually correlate the testbench data to the design activity along the time axis. This is a painfully low-tech process with inherent disparity in the design and testbench debug flows, in which the visualization "tool" is often "vi" or "emacs".

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