1. A method of converting RTL description to a computer-executable program language by a computer, the RTL description describing hardware, the hardware including a controller and a data path, the controller having a state register and a first combinational circuitry, the data path having a data-path register controlled by a control signal from the controller and a second combinational circuitry, the computer functioning as an element analyzer, a data-flow analyzer, a control-structure reconstructer, a data-flow reconstructer, a control-structure/data-flow combiner and an object-code generator, the method comprising: analyzing elements of the RTL description, at the element analyzer; creating a first data flow from the state register and a second data flow from the register in the data path, at the data-flow analyzer; reconstructing a control structure in which the controller controls the data path based on the first data flow, at the control-structure reconstructer; reconstructing the second data flow to create a data flow from the data-path register operating in each state of the control structure, at the data-flow reconstructer; mapping each reconstructed data flow in each state of the control structure, thus outputting an behavior-level intermediate language, at the control-structure/data-flow combiner; and converting the behavior-level intermediate language into a programming language executable on computer, at the object-code generator.