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Goals for Today
Today we want to learn about the microprocessor, the key component, the brain, of a computer
We’ll learn about the function of a microprocessor
And its various sub-systems
- Bus interface unit]
- Data & instruction cache memory
- Instruction decoder
- Arithmetic-Logic unit
- Floating-point unit
- Control unit Docsity.com
Microprocessor
- The key element of all computers, providing the mathematical and decision making ability
- Current state-of-the-art microprocessors (Pentium, Athlon, SPARC, PowerPC) contain complex circuits consisting of tens of millions of transistors
- They operate at ultra-fast speeds – doing over a billion operations every second
- Made up from a semiconductor, Silicon
Those components are …
- Devices
- Transistors
- Diodes
- Resistors
- Capacitors
- Wires
- And are made of the following materials
- Silicon - semiconductor
- Copper - conductor
- Silicon Dioxide - insulator
A microprocessor system?
- Microprocessors are powerful pieces of hardware, but not much useful on their own
- Just as the human brain needs hands, feet, eyes, ears, mouth to be useful; so does the microprocessor
- A microprocessor system is microprocessor plus all the components it requires to do a certain task
- A microcomputer is 1 example of a microprocessor system
QUESTION:
Why do we ever build just microprocessors
Why not just build micro-controllers that
contain everything on chip?
Post your answers on the CS101 message board
More than 90% of the microprocessors/micro-controllers manufactured are used in embedded computing applications
In 2000 alone, 365 million microprocessors and 6. billion micro-controllers were manufactured
Solution to the Bottleneck Problem
- Make the main memory faster
- Problem with that approach: The 1-ns memory is extremely expensive as compared the currently popular 100-ns memory
- Another solution: In addition to the relatively slow main memory, put a small amount of ultra-fast RAM right next to the microprocessor on the same chip and make sure that frequently used data and instructions resides in that ultra- fast memory
- Advantage: Much better overall performance due to fast access to frequently-used data and instructions
On-Chip Cache Memory (1)
- That small amount of memory located on the same
chip as the microprocessor is called On-Chip Cache Memory
- The microprocessor stores a copy of frequently
used data and instructions in its cache memory
- When the microprocessor desires to look at a piece
of data, it checks in the cache first. If it is not there, only then the microprocessor asks for the same from the main memory
Microprocessors Building Blocks
Registers
Registers
Microprocessor
Instruction Cache
Arithmetic & Logic Unit
Control Bus Unit Interface Unit
Data Cache
Instruction Decoder
I/O
RAM
Memory Bus
System Bus (^) Floating Point Unit
Instruction Decoder
- This unit receives the programming instructions and
decodes them into a form that is understandable by the processing units, i.e. the ALU or FPU
- Then, it passes on the decoded instruction to the
ALU or FPU
Arithmetic & Logic Unit (ALU)
- Also known as the “Integer Unit”
- It performs whole-number math calculations (subtract, multiply, divide, etc) comparisons (is greater than, is smaller than, etc.) and logical operations (NOT, OR, AND, etc)
- The new breed of popular microprocessors have not one but two almost identical ALU’s that can do calculations simultaneously, doubling the capability
Registers
- Both ALU & FPU have a very small amount of super-
fast private memory placed right next to them for their exclusive use. These are called registers
- The ALU & FPU store intermediate and final results
from their calculations in these registers
- Processed data goes back to the data cache and
then to main memory from these registers
Control Unit
- The brain of the microprocessor
- Manages the whole microprocessor
- Tasks include fetching instructions & data,
storing data, managing input/output devices
