A FLOATING-POINT TO FIXED-POINT ASSEMBLY PROGRAM TRANSLATOR FOR THE TMS-320C25

A floating-point digital signal processor-like programming environment is developed for the Texas Instruments TMS 320C25, a fixed-point digital signal processor. Programmers first develop an assembly program using a hypothetical floating-point instruction set and a floating-point data format. Then, floating-point simulation of the assembly program is conducted not only for verifying the program but also for estimating the range of each internal variable. This program is then automatically translated into a fixed-point version. The scaling that is needed for the conversion of floating-point variables and data to fixed-point counterparts is conducted based on the range of the signal being processed. Since the floating-point program is executed after being converted to a fixed-point version, the execution speed is not sacrified. In addition, the implementation result shows a higher SQNR than that employing conventional scaling approaches because scaling is conducted based on the statistics of a real signal. Therefore, this software provides the convenience of floating-point programming without sacrificing the advantages of fixed-point digital signal processors. Application examples for a fourth-order IIR filter, Levinson-Durbin's recursion, and an FFT routine are presented.