Data wordlength reduction for low-power signal processing software

Reducing power consumption prolongs battery life and increases integration. In digital CMOS designs, switching activity is closely connected with the total power consumption. Switching activity on programmable processors implementing linear filters, fast Fourier transforms, and other signal processing operations is dominated by the hardware multiplier. In this paper, we employ wordlength reduction of multiplicands to reduce switching activity in hardware multipliers using truncation and signed right shift methods. For 32 bit × 32 bit Wallace and radix-4 modified Booth multipliers, truncation by 16 bits achieves a 4:1 and 2:1 reduction, respectively, in switching activity, whereas signed right shift gives little or no reduction. The key contribution of this paper is the reduction of power consumption by altering multiplicands in software without any hardware modifications.