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Looking Under The Hood Of The Processor - Coggle Diagram
Looking Under The Hood Of The Processor
Major CPU components and what they are for
Control Unit (CU)
The Control Unit is what directs the operation of the CPU.
Cache
Cache is a high speed form of memory which is located closer to the CPU than the main memory but in doing so sacrifices storage capacity. the usual size of Cache is somewhere around 16-64KB
Arithmetic Logic Unit (ALU)
The ALU performs logical calculations such as addition and multiplication.
The main registers
Memory Address Register (MAR)
The MAR holds the address of the current instruction that is to be fetched from memory, or the address in memory to which data is to be transferred
Current Instruction Register (CIR)
The CIR is the part of a CPU's control unit that holds the instruction currently being executed or decoded
Program Counter (PC)
The Program Counter has the address of the next instruction to be executed from memory
Memory Data Register (MDR)
The MDR holds the contents found at the address held in the MAR, or data which is to be transferred to primary memory
The Fetch Decode Execute cycle (FDE)
1.) The memory address held in the program counter is copied into the MAR.
2.) The address in the program counter is then incremented - increased by one. The program counter now holds the address of the next instruction to be fetched.
3.) The processor sends a signal along the address bus to the memory address held in the MAR.
4.) The instruction/data held in that memory address is sent along the data bus to the MDR.
5.) The instruction/data held in the MBR/MDR is copied into the CIR.
6.) The instruction/data held in the CIR is decoded and then executed. Results of processing are stored in the accumulator
7.) The cycle then returns to step one.
How to increase the performance of the CPU
Increase the cache size
Having more cache means more instructions can be stored there meaning less data needs to be sourced from main memory which is considerably slower than cache so it means instructions can be processed quicker as they take less time to arrive.
Increase the number of cores
Having more cores means that more calculations can be performed simultaneously therefore increasing performance.
Increase the clock speed
Clock Speed: number of FDE cycles per second measured in Gigahertz.