Computer Architecture: General Registers and Organization

Study Notes

The CPU (Central Processing Unit) is the brain of the computer, executing instructions from programs through a cycle of fetching, decoding, executing, and storing.

Control Unit (CU): manages and executes instructions, performing tasks such as instruction fetch, decoding, execution, and control flow management.
Arithmetic Logic Unit (ALU): executes operations speedily, performing arithmetic and logical operations.
Memory or Storage Unit: stores and accesses data, categorized into Primary Memory (RAM) and Secondary Memory (Hard Disk).
Registers: provide small, fast storage locations that hold data temporarily during instruction execution.

Instruction Fetch: fetches instructions from RAM.
Instruction Decoding: decodes fetched instructions to operate.
Instruction Execution: sends control signals to perform operations like ALU for arithmetic and logical operations.
Control Flow Management: controls flow by updating the program counter.
Exception Handling: manages exceptions and interruptions like hardware failures, system calls, and external events.
Synchronization: facilitates the coordination of instruction execution across several cores.

Arithmetic Operations: performs basic arithmetic operations.
Logic Operations: performs logical operations like AND, OR, NOT, XOR, and bit-shifting operations.

Primary Memory (RAM): used for short-term, fast data access, essential for active program execution.
Secondary Memory (Hard Disk): provides permanent data storage.

Performs arithmetic and logic operations.
Directs the operation of the processor.
Directs Input and Output units.
Contains registers for temporary data storage and holding data during program execution.
Executes instructions by fetching, decoding, and executing them.

A set of flip-flops forms a register.
Registers provide temporary storage locations for data.
Registers support fast access to data and save the status of the CPU and data about the directly implementing program.

A general organization of seven CPU registers is displayed in the figure.
The CPU bus system is managed by the control unit.
The control unit dictates the data flow through the ALU by choosing the function of the ALU and components of the system.