Microarchitecture

Intel_Core2_arch

Single_bus_organization

Intel_i80286_arch

Microarchitecture

Microarchitecture, also known as computer organization and sometimes abbreviated as µarch or uarch, is the way a given instruction set architecture (ISA) is implemented in a particular processor. A given ISA may be implemented with different microarchitectures; implementations may vary due to different goals of a given design or due to shifts in technology.

Components of Microarchitecture

Microarchitecture encompasses several key components, including:

• Arithmetic logic unit (ALU)
• Control unit
• Registers
• Cache
• Buses
• Pipeline

Arithmetic Logic Unit (ALU)

The ALU is a critical component of the microarchitecture, responsible for performing arithmetic and logical operations.

Control Unit

The control unit directs the operation of the processor. It tells the computer's memory, ALU, and input and output devices how to respond to the instructions that have been sent to the processor.

Registers

Registers are small storage locations within the CPU that hold data temporarily. They are used to store intermediate results and frequently accessed data.

Cache

Cache is a smaller, faster memory that stores copies of the data from frequently used main memory locations. There are typically multiple levels of cache (L1, L2, and sometimes L3).

Buses

Buses are communication systems that transfer data between components inside a computer, or between computers.

Pipeline

Pipelining is a technique where multiple instruction phases are overlapped. It allows for faster processing by executing multiple instructions simultaneously.

Microarchitecture Design

Microarchitecture design involves several stages, including:

• Instruction fetch
• Instruction decode
• Execution
• Memory access
• Write-back

Instruction Fetch

The instruction fetch stage retrieves an instruction from memory.

Instruction Decode

The instruction decode stage interprets the instruction and prepares the necessary resources for execution.

Execution

The execution stage carries out the instruction.

Memory Access

The memory access stage reads or writes data from or to memory.

Write-back

The write-back stage writes the results of the instruction back to the register file.

Examples of Microarchitectures

Some well-known microarchitectures include:

• Intel Core
• AMD Zen
• ARM Cortex
• MIPS

Related Pages

• Central processing unit
• Instruction set architecture
• Computer architecture
• Superscalar processor
• Out-of-order execution
• Branch prediction
• Speculative execution