Components of the System Unit
The Machine Cycle
1. Retrieve the next instruction from memory (as indicated by the program counter) and then increment the program counter.
Execute
Fetch
2. Decode the bit pattern in the instruction register.
Decode
3. Perform the instruction required by the instruction in the instruction register
Basic Organization of Microcomputers
CPU
CU
INPUT OUTPUT REGISTER FILE MEMORY
ALU
CPU
Central Processing Unit
The heart of a computer The circuitry that controls the manipulation of data and execution of instructions
CPU
Central Processing Unit
Performs control, logical and arithmetic operations Contains the Arithmetic and Logic Unit, register sets and the Control Unit
CPU
Central Processing Unit
The CPU communicates with the storage system (memories) and the input-output (I/O) system using buses
Gates
The CPU is amazingly small given the immense amount of circuitry it contains
Circuits of a computer are made of gates
Transistor
The CPU is amazingly small given the immense amount of circuitry it contains.
Gates, however are also made of another tiny component called a transistor, and a modern CPU has millions of transistors in its circuitry.
Moore’s Law
According to Moore’s Law, the transistor count of the integrated circuits doubles every year
Transistor Count
Processor 16-Core SPARC T3 Six-Core Core i7
8-Core POWER7 Quad-Core z196 Dual-Core Itanium 2 Quad-Core Itanium Tukwila 8-Core Xeon NehalemEX 10-Core Xeon Westmere-Ex Transistor Count Date of Introduction Manufacture r
1,000,000,000 1,170,000,000
1,200,000,000 1,400,000,000 1,700,000,000 2,000,000,000 2,300,000,000 2,600,000,000
2010 2010
2010 2010 2006 2010 2010 2011
Sun/Oracle Intel
IBM IBM Intel Intel Intel Intel
Source: http://en.wikipedia.org/wiki/Transistor_count
ALU
Arithmetic and Logic Unit
Performs the arithmetic, logical and shift