A method for detecting a pattern from an arithmetic logic unit (ALU) in an integrated circuit. The method includes the steps of: generating an output from an ALU; bitwise comparing the ALU output to a pattern to produce a first output; inverting the pattern and comparing the ALU output with the inverted pattern to produce a second output; bitwise masking the first and second outputs using a mask of a plurality of masks to produce third and fourth output bits; combining the third and fourth output bits to produce first and a second output comparison bits; and storing the first and second output comparison bits in a memory.