Impact of control flow blocks granularity on custom processor design time

One of the key issues for system level design topic is the design time. This paper describes custom processor design tool as part of C-to-hardware flow and analyses its design time. The flow starts with C code specification and ends with FPGA implementation. The way the C code is processed has impact on the flow execution time. The implemented C code processing results with Control Flow Graph (CFG), and large control flow code blocks severely prolong the overall design time. Between two possibilities for design time improvement, variations in their granularities are chosen over tool internal algorithm and data structures optimizations. For 32-point DCT test case the results show huge design time decrease at the expense on the design quality: implementation resource occupation and execution time.