GCSE AQA Computer Science (fetch-decode-execute cycle)

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NimitMistry13
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Ok so i know that data is fetched from the main memory or cache memory, stored in a register, and the program counter is incremented by 1.

But is it the ALU that decodes the instruction, or executes? I thought the ALU decodes and buses do the rest, but many websites say it's not...

thanks in advance
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winterscoming
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Buses are just the connections between the CPU and memory (or to other parts of the computer) which carry "things" (data, instructions, memory addresses) in and out of the CPU.

The ALU performs (executes) Arithmetic and Logic instructions between two numbers - e.g. Add/Subtract or Greater/Less/Equals/etc.

The CU is responsible for decoding the instruction.

There's a good explanation here: https://student.craigndave.org/video...ters-and-buses
This might help too: https://en.wikipedia.org/wiki/Instruction_cycle
Last edited by winterscoming; 1 year ago
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