Modernizing Hardware Circuits through High-Level Synthesis

This works presents a design methodology to reoptimize legacy Register-Transfer level (RTL) designs specified in synthesizable Verilog or VHDL through High-Level Synthesis (HLS). The proposed methodology is based on an RTL to C compiler that converts synthesizable RTL descriptions into functional equivalent behavioral descriptions optimized to maximize its re-usability though HLS. This implies stripping off all the timing information from the RTL description and generating only C/C++ code that is functionally equivalent that has arrays, loops and functions. Generating these structures is very important in order to maximize the re-optimization potential as commercial HLS tools make extensive use of synthesis directives in the form or pragmas (comments) that allow HLS users to control how to synthesize them. E.g., loops can be fully unrolled, partially unrolled or pipelined, arrays can be synthesized as registers, memories or fully expanded into individual flip-flops and functions inline or not. Thus, generating C/C++ code with a larger number of these structures ensures that a larger variety unique implementations with different area vs. performance and power trade-offs can be generated from the converted C/C++ code. Experimental results with a variety of applications from different domains show the effectiveness of your proposed flow.