The architecture of microprocessor chip is a description of the physical layout of the various elements that form it. It directly affects how information and electrical current flows throughout the chip.
A microprocessor can either have a CISC, or complex instruction set computer, architecture or a RISC, or reduced instruction set computer, architecture. The CISC architecture is more complex and has the ability to perform complex commands. The RISC architecture is simpler, smaller and faster.
Microprocessor architecture has evolved from single core processors to multi-core processors. Processors with two or more cores are faster because they can process multiple pieces of information simultaneously.
The basic components of microprocessor architecture include:
- ALU: The Arithmetic Logic Unit performs all arithmetic and logic operations.
- Accumulator: Holds the operands are results of operations performed by the ALU.
- PC (program counter): Holds the memory address of the next instruction to be executed.
- Status, data and address registers: The status register stores information about the result of a previous ALU operation, the data register stores data going to or coming from an I/O port or memory, and the address register stores the address of the memory location to be accessed.
- Control unit: Holds the circuitry that controls the process of executing, decoding and fetching program instructions.