Described is a signature accumulator with a first set of logic devices, a second set of logic devices, and a memory device. The first set of logic devices includes compaction logic that couples an N-bit input bus to a K-bit first intermediate bus. The second set of logic devices includes commutative arithmetic operation logic that couples both the K-bit first intermediate bus and a K-bit signature bus to a K-bit second intermediate bus. The memory storage device includes a storage element that couples the K-bit second intermediate bus to the K-bit signature bus. The K-bit signature bus is also coupled to a valid-data input signal path.