FIXED-POINT OPTIMIZATION UTILITY FOR C AND C-PROCESSING PROGRAMS(+ BASED DIGITAL SIGNAL)

Fixed-point optimization utility software is developed that can aid sc aling and wordlength determination of digital signal processing algori thms written in C or C++. This utility consists of two programs: the r ange estimator and the fixed-point simulator. The former estimates the ranges of floating-point variables for purposes of automatic scaling, and the latter translates floating-point programs into fixed-point eq uivalents to evaluate the fixed-point performance by simulation. By ex ploiting the operator overloading characteristics of C++, the range es timation-and the fixed-point simulation can be conducted by simply mod ifying the variable declaration of the original program. This utility is easily applicable to nearly all types of digital signal processing programs including nonlinear, time-varying, multirate, and multidimens ional signal processing algorithms. In addition, this software can be used to compare the fixed-point characteristics of different implement ation architectures. An optimization example for an 8 x 8 inverse disc rete cosine transform (IDCT) architecture that conforms to the IEEE st andard specifications is presented. The optimized results require 8% f ewer gates when compared with the previous best implementation.