What is Microprocessor?

What is a Microprocessor?

Microprocessors are made up of millions to billions of transistors that are etched onto a single semiconductor chip, allowing them to perform complex operations at high speeds and efficiency.

A typical Microprocessor structure looks like this:

Features

• Low Cost:
  • Enabled by integrated circuit technology.
  • Availability at minimal expense.
  • Contributes to cost-effective computer systems.
• High Speed:
  • Capable of executing millions of instructions per second.
  • Utilizes advanced technology for rapid processing.
  • Empowers quick computation and task execution.
• Small Size:
  • Utilizes very large-scale and ultra-large-scale integration.
  • Results in a compact microprocessor footprint.
  • Contributes to the downsizing of computer systems.
• Versatility:
  • A single chip can serve multiple applications.
  • Adaptable to various computing tasks.
  • Enhances flexibility and usability.
• Low Power Consumption:
  • Relies on metal oxide semiconductor technology.
  • Consumes minimal electrical power.
  • Supports energy-efficient computing solutions.
• Less Heat Generation:
  • Semiconductor-based design minimizes heat emission.
  • Reduces cooling requirements in computer systems.
  • Improves overall energy efficiency.
• Reliability:
  • Semiconductor technology leads to low failure rates.
  • Boosts overall system reliability.
  • Enhances system uptime and user experience.
• Portability:
  • Small size and low power consumption make microprocessors portable.
  • Enables the development of portable devices.
  • Facilitates computing on-the-go.

Basics of Microprocessors

A microprocessor forms the core of modern computing systems. It processes a series of instructions presented in machine language, guiding the processor's actions. During instruction execution, the microprocessor accomplishes three fundamental tasks:

• Arithmetic and Logic Operations:

  Through its Arithmetic and Logical Unit (ALU), the microprocessor carries out essential calculations like addition, subtraction, multiplication, division, and logical operations. Advanced microprocessors also handle operations involving floating-point numbers.

• Data Movement:

  The microprocessor facilitates the movement of data from one location to another within the system. This capability is crucial for data manipulation and communication between different parts of a program or system.

• Control Flow and Decision Making:

  With the aid of the Program Counter (PC) register, the microprocessor stores the memory address of the next instruction to be executed. By modifying the PC's value, the microprocessor can navigate between different instruction locations and make decisions based on conditions or branching instructions.

Microprocessor Terminologies

• Instruction Set:
  • Group of commands understood by the microprocessor.
  • Interface between hardware and software.
• Bus:
  • Conductors for data, address, and control info.
  • Types: data, address, and control bus.
• IPC (Instructions Per Cycle):
  • Measures CPU's instructions executed in a cycle.
  • Reflects CPU efficiency.
• Clock Speed:
  • Operations per second a CPU performs.
  • Measured in MHz or GHz.
• Bandwidth:
  • Bits processed in one instruction.
• Word Length:
  • Bits processed in a single operation.
  • Affects calculation range and precision.
• Data Types:
  • Supported formats: binary, ASCII, signed, unsigned.
  • Key for diverse computing tasks.

Clock Speeds of Different Microprocessors

Clock speed, also known as clock frequency or clock rate, refers to the speed at which a computer's central processing unit (CPU) performs operations and executes instructions. It is measured in Hertz (Hz) and represents the number of cycles a CPU can complete in one second. Higher clock speeds contribute to enhanced processing capabilities by allowing the CPU to execute more instructions per unit of time. This results in faster data processing and improved overall performance, making tasks such as calculations, data manipulation, and software execution quicker and more efficient.

Microprocessors are at the heart of computing devices, and their clock speed, measured in megahertz (MHz) or gigahertz (GHz), determines their processing capabilities. Here's a glimpse of clock speeds across various generations of microprocessors:

• 16-bit Microprocessors:

  • 8086: Ranged from 4.7MHz, 8MHz, to 10MHz.
  • 8088: Clock speeds exceeding 5MHz.
  • 80186/80188: Operated at 6MHz.
  • 80286: Ran at 8MHz.

• 32-bit Microprocessors:

  • Intel 80386: Clock speeds spanning from 16MHz to 33MHz.
  • Intel 80486: Ranged between 16MHz and 100MHz.
  • Pentium: Operating at 66MHz.

• 64-bit Microprocessors:

  • Intel Core-2: Clock speeds varying between 1.2GHz and 3GHz.
  • Intel i7: Ranging from 1.66GHz to 3.33GHz.
  • Intel i5: Operating between 2.4GHz and 3.6GHz.
  • Intel i3: Clock speeds ranging from 2.93GHz to 3.33GHz.

As of now, 128-bit microprocessors are not in use. This is due to several reasons:

• The 64-bit address space is far from being exhausted, with only 48 out of 64 bits utilized.
• The demand for a 128-bit address space is limited.
• A 128-bit microprocessor could result in slower performance compared to the existing 64-bit microprocessors.

Microprocessors continue to evolve, offering increased processing power and efficiency while balancing factors like clock speed, architecture, and address space.

Types of Processors

• Complex Instruction Set Computer (CISC):

  CISC, or Complex Instruction Set Computer, is a computer architecture characterized by its ability to execute complex instructions that encompass multiple low-level operations within a single instruction. This architecture aims to reduce the number of instructions required to perform a particular task. It employs a relatively small number of registers, favoring the use of memory for intermediate calculations.

  Advantages:

  • Compact code due to multi-function instructions.
  • Well-suited for high-level programming languages.
  • Reduces the memory footprint of programs.

  Examples of CISC Processors:

  • Intel 386
  • Intel 486
  • Pentium
  • Pentium Pro
  • Pentium II
  • Pentium III
  • Motorola 68000
  • Motorola 68020
  • Motorola 68040, etc.

• Reduced Instruction Set Computer (RISC):

  RISC, or Reduced Instruction Set Computer, is a computer architecture designed for simplicity and speed of execution. RISC processors use a simplified instruction set where each instruction performs a single, well-defined operation. This design allows instructions to be executed in a single clock cycle, which improves overall performance. RISC architectures typically rely on multiple registers for storing temporary data, minimizing interactions with memory.

  Advantages:

  • Faster execution due to streamlined and predictable instruction execution.
  • Well-suited for pipelining and optimization.
  • Efficient use of registers reduces memory access times.

  Examples of RISC Processors:

  • IBM RS6000
  • MC88100
  • DEC Alpha 21064
  • DEC Alpha 21164
  • DEC Alpha 21264

• Explicitly Parallel Instruction Computing (EPIC):

  EPIC, or Explicitly Parallel Instruction Computing, is a modern processor architecture that focuses on enabling parallel execution of instructions through compiler-driven techniques. It allows complex instructions to be executed in parallel without relying solely on higher clock frequencies. In EPIC architecture, instructions are encoded into 128-bit bundles, each containing multiple instructions that can be executed simultaneously.

  Advantages:

  • Effective utilization of parallelism for improved performance.
  • Reduces the need for extremely high clock frequencies.
  • Enhanced efficiency in executing complex tasks.

  Example of EPIC Processor:

  • IA-64 (Intel Architecture-64)