CPU Components Overview

Study Notes

CPU Components

Control Unit: Coordinates CPU activities, directs data flow, decodes instructions, handles execution, stores results, sends memory requests, handles command/control signals, uses status registers and clock.
Program Counter: Holds address of next instruction to execute, updates with sequential instructions or jumps.
Memory Address Register: Stores address of memory location for reading/writing data, sends addresses to memory via address bus.
Memory Data Register: Temporarily stores data read from or written to memory, acts as a gateway between the CPU and memory, often referred to as the memory buffer register.
Current Instruction Register: Holds current instruction being executed, receives data copied from the memory data register, contains the opcode and operand.
Arithmetic Logic Unit (ALU): Performs arithmetic and logical operations on data, including addition, subtraction, multiplication, division, bitwise shifts, comparisons, and Boolean logic, uses general-purpose registers.
Accumulator: One of many general-purpose registers, stores data or control information, temporary storage for calculations.

CPU Buses

Address Bus: Unidirectional, carries memory addresses from CPU to memory, identifies data location for reading/writing.
Data Bus: Bi-directional, carries binary data between the CPU and memory.
Control Bus: Bi-directional, carries command and control signals between CPU components, sends memory read/write signals, handles bus requests and grants, interrupts.

Assembly Language

Mnemonics: Short, three or four-letter codes representing instructions, often used in assembly code.

Other Key Components

Decode Unit: Processes fetched instruction bits, acts like a lookup table to determine the operation code and prepare for instruction execution.
Status Register: Contains information about CPU states, individual bits act as "flags" that can be checked for various statuses.
Clock: Generates pulses at a constant rate, measured in Hertz (Hz), determines the CPU's clock speed, a higher clock rate generally corresponds to faster computer performance.
Interrupt Register (Interrupt Control Register): Checked by the CPU for interrupt requests, triggers interrupt service routines to handle requests, interrupts can come from various sources like keyboard events.
Cache: Small area of memory, located on or near the CPU, provides faster access to frequently used instructions and data, usually categorized as Level 1, 2, or 3, with lower levels having faster access speeds but smaller capacity.

Description

This quiz covers the essential components of a CPU, including the Control Unit, Program Counter, and ALU. Understand how these components interact to execute instructions and manage data flow within a computer. Test your knowledge on the functions and roles of each part.