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Topic 2 Central processing unit (CPU) (CPU with the system bus…
Topic 2
Central processing unit (CPU)
Processing Organization
Interconnection of the major component of a CPU to computer system via system bus
CPU with the system bus
i)arithmetic and logic unit (ALU)
do the actual computation (calculation)
ii) control unit (CU)
Control the movement of data and instructions into and out of the processor
iii) Register
To store instruction, data and the locations of the instruction temporarily
Data bus - carry data
Control bus- regulate the activity of bus
Address bus -collection of wires used to identify location in main memory
Tasks of processor
Fetch instructions
the processor reads an instruction from memory (register, cache, main memory)
Interpret instruction
the instruction is decoded to determine what action is required.
Fetch data
the execution of an instruction may require reading data from memory or an I/O module.
Process data
the execution of an instruction may require performing some arithmetic or logical operation on data.
Write data
the results of an execution may require writing data to memory or an I/O module.
Machine cycle
Fetch
fetching the instruction or data item from memory
Decode
decoding the instruction into commands the computer understands
Execute
executing the commands
Store
storing or writing the result to memory
Fetch and decode is called fetch cycle, execute and store called execute cycle
Pipelining
A technique where multiple instructions are overlapped in execution and is much like an assembly line
Each stage completes a part of an instruction in parallel.
Pipelining can execute more instructions in a shorter period of time.
Pipelining does not decrease the time for individual instruction, it increase instruction throughput
Microprocessor Technology
transistor-transistor logic (TTL)
Is most commonly used
emitter-coupled logic (ECL)
Greater speed but consume more power
four-bit device, while inexpensive, are good only for simple control application
complementary-metal-oxide semiconductor (CMOS)
Favored for portable computers and other devices because low power consumption
Machine Cycle
I-time
I-time or instruction time is defined to be the time taken to fetch an instruction or data from memory and stored in the instruction register.
It is the first half of the instruction cycle
E-time
E-time or execution time is defined to be the time taken to decode and execute the instruction
History of Microprocessor
8080 - First 8-bits machine
80386-first 32-bit machine, able to multi-tasking
Pentium I -First chip form the fifth generation of microprocessor
Pentium M- 32-bits processor, consume less energy and prolong battery life
AMD- significant rival to Intel in the market, invented chip: K5, K6, Athlon, Duron, and Sempron
Intel Itanium- 64-bits processor bus and have 28 register
Wong Cong Zhi 1181100850
Lee Wei Yang 1181100308
Denesh A/L Muthu
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