The accumulator-based ST6 with only 40 instructions is a low-end µC with two 8-bit index registers; two 8-bit, general-purpose registers; an 8-bit accumulator register; and a 12-bit program counter.
The COP8's accumulator-based architecture includes six to eight control and data registers, one of which is an 8-bit program-status register. The CPU also includes two 8-bit address registers, a ...