Microprocessors: Functions and Components

• Microprocessors are a key part of computer architecture and organization.
• Microprocessors are the key component of a computer, acting as its brain.
• Microprocessors' functions include processing data and executing instructions.
• Microprocessors have various subsystems including:
  • A bus interface unit
  • Data and instruction cache memory
  • An instruction decoder
  • An arithmetic-logic unit
  • A floating-point unit
  • A control unit
• Microprocessors are the key element; they make decisions and perform mathematical calculations.
• Modern microprocessors such as Pentium, Athlon, SPARC, and PowerPC contain tens of millions of transistors.
• Microprocessors operate at ultra-fast speeds, performing over a billion operations per second.
• Microprocessors contain Silicon semiconductors.

Integrated Circuits

• Integrated Circuits are commonly known as an IC's or chips.
• Integrated Circuits contain electronic parts on silicon chips and other components.
• Integrated Circuits include transistors, diodes, resistors, capacitors and wires.
• Integrated Circuits are made of silicon, copper and silicon dioxide.

Microprocessor Systems and Micro-controllers

• Microprocessors are powerful pieces of hardware, but are more useful when connected to other components.
• A microprocessor System is components combined to execute tasks.
• A computer is an example of a Microprocessor System.
• Micro-controllers are another type of microprocessor system.
• Micro-controllers are low cost and embedded in devices like video games, VCRs, microwave ovens, printers, and vehicles.
• Micro-controllers contain Input & Output capability and memory on a single chip and sometimes specialized components.
• Ninety percent of microprocessors and micro-controllers are in embedded computing applications devices.
• In 2000, 365 million microprocessors and 6.4 billion micro-controllers were manufactured.

Memory Bottleneck and Solutions for Improvement

• Modern microprocessors quickly process large amounts of data.
• Microprocessors require quick data access to maximize performance.
• Inefficient data causes reduced performance and wasted power.
• Current Microprocessors process instructions in around 1 ns.
• Main memory (RAM) data take takes about 100 ns to fetch.
• A solution is to make main memory faster but the 1-ns memory solution is expensive as compared to the 100-ns memory.
• Another solution is to add a small amount of ultra-fast RAM next to the microprocessor, which can solve the bottleneck problem.
• Ultra-fast RAM ensures frequently use data and instructions in ultra-fast memory.
• Overall performance is much better due to fast access to frequently-used data and instructions.

On-Chip Cache Memory

• On-Chip Cache Memory is a small amount of memory located on the same chip as the Microprocessor
• Microprocessors store a copy of repeatly used data and instructions in its Cache Memory.
• Microprocessors check the cache first when looking for data and then checks the main memory if nothing found.
• Small size and proximity to microprocessor make for short access times, increasing performance.
• Microprocessors predict data for future calculations and pre-fetches data and places it in the cache.
• Cache memory advantages depend on algorithms utilized for deciding what to put in cache memory.

Bus Interface Unit

• Recieves Instructions & Data from main memory.
• Sends instructions to instruction cache and data to data cache.
• Receives processed data and sends information to main memory.

Instruction Decoder

• The instruction decoder receives programming instructions and decodes them.
• It decodes information into a format the ALU or FPU understands.
• Then, it passes the decoded instructions to the ALU or FPU.

Arithmetic and Logic Unit

• The Arithmetic and Logic Unit is also known as the "Integer Unit".
• It performs math calculations like division, multiplication, addition, and subtraction.
• It makes comparisons (greater than, less than) and logical operations (NOT, OR, AND, etc).
• Newer Microprocessors have 2 ALU's, doubling the capability to perform calculations simultaneously.

Floating-Point Unit

• The Floating-Point Unit is also known as the "Numeric Unit"
• It performs calculations that involve numbers represented in the scientific notation.
• Scientific notation can represent extremely small and extremely large numbers.
• Floating-point calculations are required for graphics, scientific, and engineering work.
• ALU's can perform floating-point calculations, but they will be very slow.

Registers

• Both the ALU and FPU contain small amounts of fast memory for exclusive use.
• These units are called Registers.
• The ALU and FPU store intermediate and final results from their calculations in registers.
• Processed data goes from registers to data cache back to the main memory.

Control Unit

• The control unit manages the microprocessor.
• The control unit tasks include fetching instructions and data, storing data, and managing input/output devices.

Instruction Set

• An instruction set is a set of machine instructions that a microprocessor uses.
• An instruction set includes low-level instructions such as add, subtract, multiply, and divide.
• Each Microprocessor family has its own unique instruction set.
• High cost/lower efficiency comes from larger instruction sets, but programs are shorter to write.

Computing History

• The first Microprocessor was the Intel 4004, launched in 1971.
• The Intel 4004 had 2250 transistors.
• The Intel 4004 had 108 kHz speed with 60,000 ops/sec.
• The Intel 4004 had 16 pins.
• The Intel 4004 was a 10-micron process.
• The Intel 4004 was equal to the ENIAC, which occupied a room and used 18000 tubes.
• The Intel 4004 targeted calculators and cost less than $100 dollars.
• Busicom wanted Intel to design 16 IC's for calculators.
• Intel did not have enough resources for all of the IC's.
• Tad Hoff suggested one chip, resulting in the 4004.
• Intel realized the 4004 had many other uses.
• In December 2001 Intel launched the Pentium 4 (2.2 GHz).
• The Pentium 4 has 55 million transistors.
• The Pentium 4 has 32-bit word size.
• The Pentium 4 has 2 ALU's working at 4.4 GHz each.
• The Pentium 4 has 128 bit FPU's.
• The Pentium 4 is a 0.13 micron process.
• The Pentium 4 is targeted for PC's and low end work stations at a rough cost of $600.

Moore's Law

• In 1965, co founder of Intel, Gordon Moore, predicted the number of transistors on an IC would double every year.
• Moore later modified the prediction to every 18 months.
• 2002 Still finds Moore's prediction true.
• The time required for doubling transistor count is shrinking to a year.

Word Length

• The 4004 processed data in chunks of 4 bits.
• The Pentium 4 processes data in chunks of 32-bit length.
• The Itanium processors can process 64 bit chunks.

Enhancing Microprocessor Capability

• Frequency can be enhanced by the clock.
• The capability can be enhanced when word-width is increased.
• Caching algorithm and size can also be enhanced for an increased capability.
• Effectiveness is increased when there is greater right cache size.
• Functional units can be added for improved capabilities.
• Functional units include ALU and FPU
• Improving architecture enhances the capability of the architecture.

Explore the primary functions, components, and critical aspects of microprocessors within computer systems. Understand their role, composition, and the importance of quick data access for optimal performance. Also, learn about microprocessor systems.