The commercial microprocessor fabricated using the MOS technology is normally contained in a single chip. The microprocessor is comprised of a register section, one or more ALUs and a control unit. Depending on the register section the microprocessor can be classified either as an accumulator based or a general purpose register based machine.

In an accumulator based microprocessor such as the Intel 8085 and Motorola 6809, one of the operands is assumed to be held in a special register called the accumulator. All arithmetic and logic operations are performed using this register as one of the data sources. The result after the operation is stored in the accumulator. Read More