Totally Self-Checking Checkers for Low-Cost Arithmetic Codes

This paper presents totally self-checking (TSC) checkers for low-cost AN codes with generator A = 2r −1. These checkers are composed of two different parts. The first part is a TSC residue generator modulo (22r − 1), and the second part is a TSC checker for the same low-cost AN code with code length 2r. There are r output lines with two code output states: the all O\´s and the all 1\´s states, which can be reduced to 1-out-of-2 code output states by using a "counter-driven comparator." These checkers have the same number of output lines, but they are faster, more economical, and more reliable, compared to the corresponding checkers based on the computation of the residue modulo 2r − 1 of the input states.