Arithmetic Circuit Optimization in Finite Word Length Approximation of Arbitrary Functions
Takao Sasaki, Koji Kotani, Hisamishi Toyoshima · ITC-CSCC :International Technical Conference on Circuits Systems, Computers and Communications · 2008
In digital circuit design using a hardware description language, some elementary functions and user defined functions can not be expressed directly. In such cases, the target function is approximated as a polynomial to be implemented by additions and multiplications. If an approximation error exceeds the permissible one, it can be corrected with a look-up table (LUT). However, considering discrete and nonlinear relation between the approximation error and the circuit area, optimization of reducing the total hardware cost would be more complex. In this research, for an arbitrary function, we propose the optimization technique of minimizing the hardware cost. The proposed method starts with multiple initial solutions based on two hardware models. Furthermore, for optimization algorithm, tabu search (TS) is used, and it is parallelized to make a global search.