Higher Computing Science The Processor

2. Von Neumann Architecture
Main
Memory
Output
Devices
Input
Devices
Backing
Storage
ProcessorProcessor

3. The Processor
Arithmetic and Logic Unit (ALU)
Carries out calculations e.g.
10110011
+ 11110010
Performs logical operations e.g.
AND, OR, NOT
ALU

4. The Processor
ALU
Control
Unit
Control Unit
Manages the
fetching
decoding
and
executing
of instructions

5. The Processor
ALU
Control
Unit
Memory
Data
Register
Memory
Address
RegisterOther
Registers
Registers
Very fast temporary storage locations which
hold:
•data being processed
•instructions being executed
•addresses of memory locations to be accessed

6. The Processor
ALU
Control
Unit
Memory
Data
Register
Memory
Address
RegisterOther
Registers
Common Registers
Instruction Register (IR)
Holds the instruction currently being executed by
the processor
Accumulator (A)
Stores the results of arithmetic calculations
Program Counter (PC)
Stores the address of the instruction currently
being executed.

7. Multi Core Processor
• The first processors only had one core, so could only execute a single
instruction at any given time
• A multi core processor is a single chip with two or more independent
processing units built into it
• Multi core processors can execute two or more instructions at any given
time

8. Multi Core Processor
• Dual-core (2), quad-core (4) are common but also 8 core processors and
above are available
• Need to consider specification more carefully
e.g. 3.6GHz CPU single-core vs 2.8GHz dual-core
• Used in high end applications and gaming