Automatic generation of VHDL hardware code from data flow graphs

The Software/Hardware Implementation and Research Architecture (SHIRA) is a C to hardware toolchain developed by the Computer Architecture Research Group (CARG) of the University of Ottawa. The framework and algorithms to generate the hardware from an Intermediate Representation (IR) of the C code is needed. This paper presents the conceiving, design, and development of a module that generates the hardware for custom instructions identified by specialized SHIRA components without the need for any user interaction. The module is programmed in Java and takes a Data Flow Graph (DFG) as an IR for input. It then generates VHDL code that targets the Altera Field Programmable Gate Arrays (FPGA). It is possible to use separate components for each operation or to set a maximum number for each component which leads to component reuse and reduces chip area use. The performance improvement of the generated code is compared to using only the processor's standard instruction set.