Microprocessor anatomy

Microprocessor anatomy

The microprocessor is a multifunction integrated circuit made up of several parts that work together to execute the instructions passed to the CPU. The primary parts of the microprocessor.

Arithmetic and Logic Unit (ALU): The ALU performs the numerical calculations (except those done by the FPU) and comparative logic functions, including all add, subtract, divide, multiply, equal to, greater than, less than, and other arithmetic and logic operations.

l Bus Interface Unit (BIU): The BIU supervises the transfer of data over the bus system between devices and the CPU and serves as the interface point for the CPU and the external bus for the CU.

l Control Unit (CU): It may sound obvious, but the control unit controls the processor's functions by telling the other parts of the CPU how to operate, what data to use, and where to put the results.

l Decode Unit: Most program instructions are combinations of simpler instructions. The decode unit decodes incoming instructions into individual CPU commands.

l Floating Point Unit (FPU): The FPU handles the floating point operations for the ALU and CU.

Floating point operations involve arithmetic on numbers with decimal places and higher math operations such as trigonometry and logarithms. The FPU also may be called the math

Coprocessor, the Numerical Processing Unit (NPU), or the Numerical Data Processor (NDP).

l Memory Management Unit (MMU): The MMU handles the addressing and cataloging of where data is stored in RAM and cache memory. Any data that the CPU needs from memory is requested from the MMU. The MMU manages memory segmentation and paging allocations and translates all logical addressing into physical addressing.

l Pre-Fetch Unit: The Pre-Fetch Unit preloads the CPU's instruction registers with instructions whenever the BIU is idle, which allows the CPU to look ahead at future instructions.

l Protection Test Unit (PTU): Works with the CPU to monitor that functions are carried out correctly. If it detects something done improperly, it generates an error signal.

l Registers: Built into the CPU are a number of holding areas and buffers used to temporarily hold data, addresses, and instructions being passed around between the CPU's components.